Uncategorized - Modern Airliners - Part 2

Airbus announces the end of A380 production.

Emirates Airbus A380-861

European aviation powerhouse, Airbus, announced, not unexpectedly, that they would cease production of the A380 Super Jumbo.

The huge double-decker A380 was set to revolutionise air travel in the new millennium and give stiff competition to the Boeing 747 Jumbo. Able to carry over 500 passengers across long distances, the A380 looked like a sure bet in that niche market. Launched in 2008 by Singapore Airlines, the future looked hopeful with orders from many of the worlds prestigious airlines. Notably, Middle Eastern airline giant, Emirates, ordered a whopping 162 airframes. Airbus expected to sell around 1,200 A380s in order to recoup development cost, and of course, turn a profit. The actuality is that they have not even achieved a quarter of this target. As at the 31st of January 2019, 234 A380s have been delivered with 232 in active service. Of these 106 are with Emirates.

Where did Airbus go wrong? Like anything in the commercial world, the economics no longer stack up. The high price of the aircraft, coupled with the extensive upgrades required at airfields, before they can accommodate the Super Jumbo, led to very high overheads. Aviation, like most industries with an accent on technology, are ever changing. It can be very difficult to predict future trends, and Airbus is not alone in this. Boeing also got burned by this trend with their 747-8i. Designed as the descendant of the much loved 747, it met with a very lukewarm reception and has since ceased production. Boeing at least could fall back on the original failsafe of the 747, by creating a freighter version of the 747-8. This has done slightly better. The bubble on the original 747 was to enable a freighter version to be loaded through an opening nose door. They didn’t have faith that the passenger version would sell, so took an “each way bet”.

The focus seems to be now moving toward the long-range twin-jets. Both Boeing and Airbus have a wide range of offerings in this space, which offer airlines a wide choice across their whole network. The economics of filling one very large aircraft to the point of profitability can very challenging. With slightly smaller aircraft, routes can be flown more frequently and economically. Today’s giant twins like the Airbus A350-11 and the Boeing 777-9, are coming online and are enabling airlines to offer non-stop services between cities where it has not been possible in the past. Airlines, like QANTAS, are rethinking their strategy and proposing services that to date have not been possible.

An Airbus A380 destined for Emirates takes shape in the Toulouse factory. When production ends for the Super Jumbo in 2021, there are an estimated 3,500 jobs that will be at risk.
An Airbus A380 destined for Emirates takes shape in the Toulouse factory. When production ends for the Super Jumbo in 2021, there are an estimated 3,500 jobs that will be at risk.

Only a few days ago QANTAS announced that they would no longer require the remaining 8 A380s in the order book. Virgin Atlantic also withdrew their order of 6, as they no longer wish to take up the A380. The final crunch came when Emirates announced it would reduce its order of 162 by about 20 aircraft. Once the balance of the Emirates and A.N.A. orders are fulfilled, there is no further backlog. Airbus anticipate closing production in 2021, which could impact up to 3,500 jobs. Not only will this affect Airbus, but also the many suppliers who create components for the giant aircraft.

It seems the A380 came along just a little late in the day. The focus of aviation has changed once again and it seems the day of the giant 4 engined Jumbo is over.

QANTAS Airbus A380 Orders Capped at 12.

QANTAS A380 VH-OQA taking off

Back in 2006, QANTAS was one of the first airlines to place an order for the Airbus A380 Super Jumbo. 20 of the type were ordered which certainly lifted the QANTAS image as an industry leader. On 21 September 2008, the first A380, registration VH-OQA named for the much loved and respected aviatrix Nancy-Bird Walton landed in Sydney. Over the next 3 and a half years Airbus delivered 11 more airframes with the last of the 12 arriving in December 2011. VH-OQL, named Phyllis Arnott after the first woman in Australia to take a commercial pilots licence, is now officially the one that concluded the order.

For the last 8 years, QANTAS has had 8 A380s outstanding in their order book with Airbus. Sources at QANTAS indicate that those remaining 8 aircraft have not featured in its future network plans for some time. This week it was announced that the remaining 8 would no longer be required and in discussions with Airbus formally cancelled that remaining order. This is no doubt bad news for Airbus as this cancellation is a significant contributor to the $US4 billion in lost contracts. Airbus is putting a brave face on it, one source quoted as saying, “one month does not make a year”. Let’s hope they’re right.

When we look at the order book for the A380 as at the end of January 2019, we see there are 313 orders with 234 airframes delivered of which 232 are currently in active service. The QANTAS order for 20 aircraft was the third largest behind Singapore Airlines and Emirates. The Emirates order itself is what is keeping the A380 factories open. Of the 162 ordered by the giant airline, 109 have been delivered. We also note that Virgin Atlantic who had 6 on order have now dropped off the order list.

Whilst Airbus might see the Emirates order as being a lifeline for the A380. There is talk that Emirates may also be rethinking their strategy and perhaps looking at the A350 as a viable alternative. As we wrote back in 2015 about the 747-8, is the day of the 4 engined Jumbo sized aircraft at an end? We can only speculate, and of course, Airbus is remaining tight-lipped, about whether we will soon see a closure of the Airbus A380 production line?

QANTAS say they are committed to the A380s in their fleet and around mid-year this year, they will embark on a revamping and upgrade of the interiors of their A380 fleet. So there certainly is committment to the type in the future.

Project Sunrise

Described as the last frontier of aviation by CEO of QANTAS, Alan Joyce, is the non-stop flight to anywhere in the world. The advent of the giant twin-engined airliners is bringing this dream into reality. QANTAS recently took delivery of its Boeing 787-9 Dreamliners which have been deployed on the Perth to London non-stop flight route. This will become available for East Coast Australian cities soon as well. Mr Joyce indicated that the aircraft are stripped back and are targeted at the higher end business market. Cargo may even be sacrificed in favour of sleeping berths for the extremely long flights.

The QANTAS Boeing 787_9 Dreamliner is pivotal in Project Sunrise, bringing more of the world into the non-stop flight umbrella.
The QANTAS Boeing 787_9 Dreamliner is pivotal in Project Sunrise, bringing more of the world into the non-stop flight umbrella.

Perhaps we are at that tipping point where those longer flights are becoming economically feasible. If we go back a few years, the Airbus A340 was given as a solution to those ultra long flights that other airliners could not compete with. Singapore Airlines pioneered some of those long routes, but eventually the economics didn’t stack up. The long-range A340 became known as a flying tanker with a few passengers allowed along for the ride.

QANTAS also introduced an extremely long route from Sydney to Dallas, Texas using their Boeing 747 400ER. It was quite a stretch, and on several occasions on the Dallas to Sydney leg which is against the jet stream, the aircraft had to stop over in Noumea due to low fuel. This route is now operated by the Airbus A380.

Orignally Mr Joyce of QANTAS was adamant that the Project Sunrise aircraft would carry in excess of 300 passengers. This has been revised back now, and may well follow the lead of Singpoare Airlines on their Singapore to New York route using an Airbus 900ULR (Ultra Long Range). This non-stop flight of 18 hours is available to 67 Business Class travellers along with 94 Premium Economy Class travellers. Certainly a high end portion of the market. For high flying business travellers, this is the quickest way to get there, so may be money well spent.

Perhaps we’re not all as keen as those business travellers to shave a few hours off our trip and pay those premium prices. But there are new aircraft being developed and improved all the time. The likely candidates are the Boeing 777X and the Airbus A350 1000. We mustn’t quite forget about supersonic travel either. Concorde may not a have flown for a decade and half, but that doesn’t mean the concept is dead.

Is Boeing buying its way into the supersonic market?

Aerion AS2 Supersonic business jet

No sooner had we posted our article on the prospects of future supersonic jets gracing our skies again, and here comes an announcement from Boeing and Aerion of Reno, Nevada. The giant plane maker, Boeing, on Tuesday 05 February 2018 made a significant investment with the experts in supersonic technology, Aerion. The financials involved have not been disclosed, but suffice to say it will no doubt help out with the US$120 million development costs for the Aerion AS2. It must have been a good deal as Boeing shares touched a record high of US$407.48 after opening above US$400 for the first time ever.

The reasoning behind the investment can best be summed up in a statement by Steve Nordlund, vice president and general manager of Boeing NeXt. He said, “through this partnership that combines Aerion’s supersonic expertise with Boeing’s global industrial scale and commercial aviation experience, we have the right team to build the future of sustainable supersonic flight.”

As a side note, Aerion and Lockheed Martin were in a Technical Viability partnership from 2017 which lapsed on 01 February 2019 to develop the AS2. Neither party expressed willingness to further this partnership. It almost seems that Boeing was waiting in the wings.

So what is the AS2? What is Boeing buying into?

The Aerion AS2 is a business jet designed to cut travel times significantly. Here are some specs.

Aerion AS2 Specs.

SpeedMach 1.4 / 1,000 mph / 1,610kph
Length49 metres
Wing Span21 metres
Wing Area125 square metres
Tail Height8 metres
Cabin Length9.1 metres
Cabin Height1.87 metres
Cabin Width2.2 metres
Engines3 x GE Affinity Turbo Fans
CockpitBy Honeywell
Thrust15,000 lbs
Max SpeedMach 1.6, Mach 0.99 over supersonic banned areas.
Range9,260 km
Landing distanceLess than 4,000 ft
Take-off distance full fuel.7,500 ft
Basic Operating weight22,588 kg
Max take-off weight52,163 kg
First Flight2023
Enter Service2025

The obvious question is, how will the AS2 suceed where Concorde failed? The restrictions for supersonic flight over land are still very much in place. Because of the sonic boom created by shock waves as the aircraft crosses the sound barrier, these aircraft are not permitted to over fly land for environmental and social reasons. So what has changed?

A model of the Aerion AS2 Supersonic Business Jet (SBJ).Note the squareness of the wings, much more like a modern fighter than the classic Concorde delta type wing.
A model of the Aerion AS2 Supersonic Business Jet (SBJ). Note the squareness of the wings, much more like a modern fighter than the classic Concorde delta type wing.

There is certainly pressure in the United States on governing bodies to relax the rules around supersonic flight over land. This may or may not be successful. However, in Europe there seems to be no appetite for relaxing these rules, and Europe of course is a huge destination for any business related travel. Relaxing of legislation, therefore, cannot be a condition that supersonic plane makers should count on.

The solution has to be in the technology. To minimise the sound shock wave as much as possible, the AS2 is designed with a very long tapered fuselage. This helps to control the length of the wave, thereby lessening the resultant boom. Aerion have developed BOOMLESS CRUISE™, which they say will enable the AS2 to cruise at speeds approaching Mach 1.2 without the sonic boom. This is dependant on temperature and wind. Once the AS2 gains certification Aerion intend to work with authorities in order to gain approval for this cruise capability.

There is a third feature in the AS2, in that it can fly just as efficiently at Mach .95 as it can at super sonic speeds. Mach .95 is still significantly faster than current passenger airliners, so with this flexibily, the AS2 certainly has the ability to suceed where Concorde failed. Whilst not as fast as Concorde, the AS2 has the capability of flying anywhere in the world without noise related restrictions. She will still have the ability to shave 3 hours off a trans Atlantic flight as compared to present day airliners, which is significant.

The AS2 will come with various cabin configuration options, from standard airliner seating to dual cabins with lounge chairs in one and a meeting table in the other.

On the outside, the AS2 is very sleek as mentioned above, with a long tapered fuselage. Aerion have done away with the delta wing of Concorde and gone for a more square wing, similar to modern fighter jets. The wing is very square with sharp angles and very thin. Originally Aerion were leaning toward two 19,000 lb thrust Pratt and Whitney engines, but changed to the present configuration of three 15,000 lb thrust GE Aviation engines. The tri-jet configuration they found offered better take-off performance.

It will be great to see supersonic travel coming back into focus. The renewed interest will no doubt lead to technological advances and enable supersonic jets to become the new normal. That, surely, will make air travel much more attractive.

Is this the return of the Supersonic Jet?

Aerion Supersonic Business Jet

A new Supersonic Jet is just around the corner.

Not since 24 October 2003, when the futuristic Concorde made her last flight, has supersonic air travel been available to the masses. Well, we use the term masses loosely. Concorde was an extremely expensive machine to run and those who flew her paid top dollar for the privilege. In addition to the high running cost, she was also limited to flying over water at supersonic speeds due to the sonic boom created by flying above the speed of sound. For environmental reasons, most countries banned the supersonic jets flying over their territory because of the sonic boom. This naturally limited the appeal of this aircraft due to the limitation of the routes it could be usefully flown over.

It is amazing to think that this technology was available until nearly two decades ago. High flying businessmen in London, for example, could go to New York, do their business, and be back home for dinner. Surely that demand is still there.

So what are the challenges that a Supersonic plane design has to overcome? The main ones are, cost to operate, sonic boom noise, landing/take-off noise and emissions.

We can agree that technology has certainly made vast improvements in the time since Concorde flew. Engine technology has enabled more power to be delivered by quieter engines. Composite materials have given higher strength to airframes at lower weights as well as lower manufacturing costs. One thing remains, however, the sonic boom. This limiting factor is still a roadblock.

There has been, over the last couple of years, increasing pressure in the U.S. for environmental standards around supersonic transport aircraft to be relaxed. There are three start-up companies that have already invested considerable money and resources into the development of their own version of a supersonic transport aircraft. These are: Boom Technologies with their Mach 2.2 capable airliner, Spike with their Mach 1.6 capable S-512 Quiet Supersonic Business Jet and Aerion with their Mach 1.4 capable As2 Business Jet. These are all slated to be ready for service between 2023 and 2025. Even the Russians are dipping their toe back in the supersonic pond, with the United Aviation Corp (UAC) aiming to start on their own offering in 2022. You may recall Russia had a Concorde look alike, the Tupolev TU-144. Dubbed, the Koncordski. This aircraft never met with any success, being used on domestic routes only, until it suffered a final setback, breaking up in flight over the Paris Air Show.


The hypersonic airliner will travel at mach 5……..


Meanwhile, the household name manufacturers are still hard on the case. Boeing has had various designs over the years to enable it to enter the Super Sonic Transport (SST) space. None have got much further than the drawing board. They are, however, working on a new concept that they hope will reinvent our expectations of fast flight. The hypersonic airliner will travel at Mach 5, which is about 3800 mph (6110 km/h) or five times the speed of sound. This is still around twenty to thirty years away and no doubt will depend on technology that to date has yet to be made available. Lockheed Martin also has an offering in the works. In 2018 Lockheed Martin was selected to design a Low Boom Flight Demonstrator(LBFD). Their X-59 QueSST (Quiet SST) will fly at 55,000 feet at a speed around 940 mph / 1,513 kph / 817 knots. The aim is to reduce the sonic boom from a boom to a light thump, a bit like car door closing.

In July 2018, the International Council on Clean Transportation (ICCT), under the lead authorship of Dan Rutherford produced a report called, “Environmental performance of emerging supersonic transport aircraft”. The report was drawn from studies and simulations carried out at Stanford University and was in response to mounting pressure on the Trump Administration to relax rules governing overland supersonic flight in the U.S.A..

The report looked back at Concorde and compared it with conventional airliners of the day, say the Boeing 747. It was obvious that in every aspect, the Concorde was less environmentally friendly. The supersonic plane was less fuel efficient, noisier at airfields, emitted higher levels of nitric oxide in the take-off and landing phases, higher levels of carbon dioxide in cruise, not to mention the sonic boom. They then looked at the situation today. As we’ve mentioned already, technology has moved forward in many aspects of aircraft manufacturing. Does this work for the supersonic jet manufacturer? Yes, of course new things are possible now that were not in the 1960s when Concorde was developed. However, the bar has been lifted as far as eco standards around commercial aircraft are concerned.

The report found that that the gap between conventional airliners and the new generation of supersonic planes was much the same as those in the time of Concorde. So, let’s say the U.S. relaxes its rules around supersonic jet travel. Will this be enough of a market for plane makers to make a profit out of? The U.S. relaxing their rules doesn’t mean other countries will follow. In fact some European countries have made it clear that they will not entertain the idea of supersonic flights over their territories. Even flying to those countries, with the last overland portion done at subsonic speeds may not work, as there are still airport noise and emission standards to overcome. So, needless to say, a complex issue.


…. around 5,000 supersonic flights a day…..


For an aircraft manufacturer, the idea is to develop an aircraft for which you have calculated there is a market which will enable you to sell enough to recoup your cost, as well as making a profit. Some of the supersonic jet maker start ups are estimating that they will be producing up to 2,000 airframes. These aircraft will serve up to 500 cities by 2035. Imagine, around 5,000 supersonic flights a day. Over a 16 hour flying day, there could be a sonic boom every 15 minutes.

Needless to say, there are exciting times ahead. We would love to see the return of supersonic flight, but in a way that is sustainable to the environment. There is no doubt that solutions to the roadblocks will be found.

How can I maximise my carry on luggage?

Wheelie bags are popular to use as carry on luggage.

How can I maximise my carry on luggage?

I remember when carry on luggage was simply a bag of goodies you took into the aircraft cabin with you to keep yourself amused for a long flight. I used to relish handing over my suitcase(s) to the check-in person and walking away almost empty-handed. For longer trips away I still enjoy that.

There is now, however, a change to the way we think about how we take our stuff with us.

Checked in luggage is becoming less common as travellers try to make use of the free carry on option.
Checked in luggage is becoming less common as travellers try to make use of the free carry on option.

The changes have several contributing factors. Firstly, we seem to spend a lot of time at airports

these days queuing for stuff. Security checks for one thing. So people are focusing more and more on how they can get through the process and be on their way more quickly. Having only a cabin bag is ideal for this as you can bypass the baggage carousels and be on your way very quickly. Secondly, the advent of unbundling airfares has led to the option, on many airlines, of paying for what you want and not what you don’t want.

…….. You can bypass the baggage carousels and be on your way……

One of the things that you often have to pay for is checked in baggage. Many travellers see this as an opportunity to be able to reduce their airfare cost. We can forego paying for meals and more desirable seats. In the same way, we can reduce the cost by carrying our bag into the cabin, not to mention the previous point of not having to wait for that last bag off the carousel at your destination.

Now, believe it or not, the airlines have also noticed this trend. When the baggage trolleys start going out to the aircraft half empty and everyone is turning up to the boarding gate with wheelie bags, something is changing. Like any business, airlines hate people getting away with something for nothing. Responding to the trend of travellers choosing to take advantage of the free carry on luggage allowance, they have started to clamp down on this allowance. In times gone by, the boarding gate people would just let you go through with your bags, provided they looked like they might fit in the overhead locker or you didn’t look like you were carrying bags of cement.

Yes, size does matter……..

Not so now. Nowadays you can expect to have your bag scrutinised, weighed and even put into that funny frame thing to check it is small enough to fit into the overhead locker or under the

Be prepared to be asked to prove that your bag is within the airline requirements.
Be prepared to be asked to prove that your bag is within the airline requirements.

seat in front of you. Yes, size does matter, but then so does weight. I wish we could say that there is a uniform rule about these weights and dimensions, but unfortunately, every airline has it’s own idea of what this should be. Checking the airline website is really the only sure fire way to know what that allowance is. This is easy if you are travelling on one airline all the way. What if, for example, you are travelling from Singapore to Copenhagen via London. You might get a nice generous allowance from Singapore to London and then on your low-cost carrier flight on to Copenhagen you get virtually nothing. This means of course that the meager allowance for the second sector becomes the governing factor for the whole trip. Unless of course, you anticipate consuming the difference on your first flight or posting the difference to Copenhagen from London.

What do we need to think about if we are choosing to go down the cabin luggage only path? First off we need to be aware of all the things that are prohibited in the aircraft cabin. It would be a depressing start to the trip if many of our items were thrown out at the security check. So first off, make sure you check with your airline website to see what the prohibited items are. These are fairly standard these days, but things do change and it pays to know, as ignorance is no defence.  Right?

Smart packing is your friend. Think about what you actually need. Many of us over-pack, just in case, you know. With clothes try and make sure you wear your heavier clothes and that the lighter weight ones are in your cabin luggage compliant bag. For example boots, jeans, jackets, belts and coats can be worn or at least thrown over your arm, well maybe not the belts, jeans or boots. I’m not saying you do a Joey Tribbiani from Friends, but you get the picture. When you do pack your clothes, roll them instead of folding them. This ensures you can use all the space most effectively and also your clothes will be less wrinkled and ready to wear when you get to your destination.

Now, toiletries. Of course, we know about the restriction on liquids in the aircraft cabin. The rule of thumb is no more than 100ml, but, yes I’m going to say it again, please make sure you check with your airline webpage to be completely sure. This means you need to pour the contents of your favourite shampoo, conditioner, etc into smaller 100ml plastic bottles. These can be purchased very cheaply and you can use them each time you travel. Make sure of course they close firmly as even in the aircraft cabin the difference in air pressure with ground level is significant enough to encourage liquids to try and leave the security of their container to go exploring in your clothes. Believe me, they prefer your clothes as it is very hard to get rid of things like shampoo and skin cream out of them.

…..contain any random liquids or creams that make good their escape.

That brings me to the next point. Your toiletries bag. Put that away in the cupboard again as it won’t help you with you space saving or weight saving. You are much better off with a plastic zip

Check with the airline website to ensure you know the cabin bag acceptable dimensions.
Check with the airline website to ensure you know the cabin bag acceptable dimensions.

lock bag. The zip lock bag can be made to lie very flat among your clothes which is a great space saving technique. In addition, the plastic is more liquid proof than some toiletrie bags and can contain any random liquids or creams that make good their escape. When you do seal your zip lock bag, ensure you remove all possible air inside the bag as this will expand like a balloon as the cabin pressure reduces on climb out.

Metal items are another area that care needs to be taken. Even though we know not to bring knives, scissors etc.. Care also needs to be taken to not include items that look like knives and scissors. For example, you can get tweezers that may have scissor type finger holes. These are to be avoided in favour of the tong style variety. What you have to think of is how it looks to the x-ray machine operator. You may well get them through security eventually but who needs the grief of having to unpack your bag to show them the offending item. It may just put them in a mood to examine other stuff or confiscate the item anyway.

So what about our ever hungry electronic equipment?

Cabin bag stowage in the overhead locker can work for everyone if you show your case on its side with the bottom of the case against the back wall.
Cabin bag stowage in the overhead locker can work for everyone if you stow your case on its side with the bottom of the case against the back wall.

So what about our ever hungry electronic equipment? No one needs the angst of thinking their gadgetry is going to run out of juice, but those plugs can weigh a bit. Consider perhaps taking only the cable part of the charger with the USB plug at the end. Most aircraft have the USB plug point for your flight, so that is covered. At your destination many hotels have USB points now, but if not smart TVs have them. If you do need to take one and your bag weight is getting up there, then maybe a jacket pocket could be the answer. This could apply to any smaller but weighty items like camera lenses and the like.

So we’ve seen how it is possible to save on your next flights. Free cabin luggage is a boon for those who can squeeze their trip into a smaller bag. Let’s make the most of this while we can as you can be sure that airlines will come round to finding a way to charge for something we are currently getting for free.

Please share any ideas you might have about maximising cabin luggage, we would love to hear them.

How to find airfare deals

Passengers boarding a Boeing 747

How to find airfare deals.

So you’re planning that special trip away, but how do you get the biggest bang for your buck when buying those flight tickets for the plane trip portion of the journey?  Like anything worth doing, finding the best airline flight deals takes a bit of planning.

Timing of your plane trip.

Airliner on approach.
If your timing is flexible then use this to your advantage.

If you have some flexibility around the timings of your trip, you can use that to your advantage. Travelling in off-peak times means you won’t be paying premium prices. Airlines, like any other business, use the supply and demand principal to maximise their return. For example, during the week you will find that early morning and late afternoon flights rarely have cheap fares available because these flights are frequented by business travellers. The airlines know that these flights will be well filled, so there is no need to offer cheaper fares. So avoid these times if at all possible. Time of the day is therefore important.

To find a cheap flight, other time factors are also just as important to consider. Times of the week also make a difference. For example, business travellers going to more distant destinations tend to go for the week. This means that Monday mornings and Friday afternoon/evenings are also peak times and unlikely times to find airfare deals. On top of that, you have weekenders departing on Friday evenings and returning on Sunday evenings.

So much to consider.

Other timings to consider in the search for your cheap flight ticket.

Ok, so we’ve considered the times above that are unlikely to provide us with good airline flight deals. That is, of course, assuming we have also ensured we’re not travelling on a public holiday or around a sports or other event. In that case, all bets are off and prices go through the roof.

If you are travelling internationally then that adds a whole extra dimension to the exercise. Not only should you consider peak times in your origin country, but also those of your destination country and countries you might be passing through along the way. For example, I once travelled to London with a stop in Hong Kong along the way. I thought I had covered all my bases, but still, I couldn’t find flight prices that I felt were a good deal. The reason I found out was that it was the end of the summer school holidays in the UK and many children attending boarding school in the UK were returning to London. Lesson learned.

Check Airline Prices.

Having done our due diligence and decided on some dates that we feel are optimum for avoiding any peak periods. What next?

Looking for a cheap fare doesn’t mean you have to travel on old aircraft. New state of the art airliners like the Boeing 787 Dreamliner, Airbus A350 or A380 are designed to fly more economically and therefore give the airlines the ability to be more competitive.

Next, we need to find out what options are out there. Which airlines fly to our chosen destination? Also, another factor to consider and decide upon is, what class of travel we want to travel in. Talking about cheap fares, we may conjure up pictures of backpackers travelling on ancient aircraft stopping in 25 mountain villages along the way, just to save a few coins. Not necessarily so, unless of course, you want it to be. A cheap flight ticket can be any ticket that is a good deal for the service you receive. So whether you want to travel first, business or economy class, the principle is the same. Airlines put out deals on flights that they are having trouble selling. So decide at the outset what level of comfort your budget will allow for.

The class decided, we start our search. To start, go to neutral online travel agency sites that sell all airlines equally. Well, that is perhaps a little naive. Even online travel agencies have preferred airlines they sell due to higher levels of return for them. With this in mind, still perform some searches on those sites. This will give you a feel for which airlines are relevant for the route you wish to fly. Also, another handy tool is Google Skyscanner. You can perform searches as you can with online travel agents and find out which airlines fly and which fares are currently on offer. You can even set up alerts so that when prices change from your preferred options you will receive an email. This can be handy in case you forget the check back and a special is released.

Once you have ascertained which airlines are relevant to your requirements, visit their websites as well. I would recommend subscribing to alerts from them so that you get to hear about specials as they start or even before they start. A special fare doesn’t mean that all seats on that airline for that route will be sold at that price. Airlines work overtime to control yield and special fares will be allocated on flights depending on their popularity. On a peak time flight, even during the special fare period you will, in all likelihood, find no special fares. On less popular travel times, however, you will find those fares.  Airlines review these constantly and will adjust the number of special fare seats up or down depending on how sales are going. Special fares work much the same as loss leaders work in other industries. For example, in your local supermarket, you see those items at the end of the aisle facing the front door being sold very visibly at knock-down prices. These items can be sold at a loss because they get people in the door and put them in a buying mood which they know will in most cases lead to sales of other items sold at the normal price.

Airlines will do the same thing. Release a very small percentage of seats at a very low price to

Airliner waiting for passengers
If airlines did not fill their flights with cheaper fares then it would cause them to lose money as those flights still have to fly, empty or not.

get people onto their website. Once there they have this idea that the prices are nice and low today, they will look and see that the special deal fares are available on flights that they don’t really like the timings of, so they look at the next fare up to see if there are better options. In their minds they have already spent the amount of the special fare and they then see the difference between that and the not so special fare as the actual amount they are spending, which doesn’t seem so bad. Boom, the airline’s plan worked.

The message here is don’t lose sight of the bottom line.  If you find the special fare is not giving you what you need, back out and keep the research going, unless you are happy with the new option you have found.

Where should I actually buy the fare?

This is a good question and no one answer is right. The travel industry can vary somewhat from country to country, but one thing you can count on is that it isn’t straight forward. We talked about online travel agency websites. These are great for seeing which airlines are the ones you should be shortlisting as logical options for the route you will be travelling. Should you buy from these websites?  Well, that depends. The travel agency needs to make money obviously, so how do they do it.  Once again there is no straight forward answer to that.  In years gone by there was a standard procedure where a travel agency sold an airline seat and the airline paid them a commission of X per cent. Easy. Now, not so much. Very few airlines are now paying commission to travel agents. Let’s take a look back a few decades.

Back in the early days of travel, we didn’t have the technology we have today. In fact, it was the airline industry that was at forefront of driving the development of computer networking. But that is an aside. In those early days, travellers had to come into an airline office to pay for their tickets. Of course it was not possible for an airline to have offices in every town village or city, so enter the travel agent who literally acted as an agent for that airline and collected money on behalf of that airline, and of course others. Now enter the online age and all of a sudden airlines can actually be everywhere. As a result, they, for the most part, have decided to stop paying those commissions that travel agents relied upon for so long.

Travel agents and airlines used to have a good working relationship as airlines couldn’t logically have an office in every town.

So who pays now? This is also not a single answer question. In most cases you, the traveller, will pay a fee. So for the travel agency website you may well see some cheap fares but beware of the fees at the end, they may well undo the advantage you gained by finding a cheap fare on their site. However, don’t discount using these agency sites. Some travel agencies have such high brand recognition that they can command respect from the airlines due to the high turnover of travel sold on their site. In a case like this, an airline might offer the travel agency net fares which are far below even what the airline is selling them for. The travel agency will mark them up and the mark-up will be their profit.  They will mark them up to such a level as to ensure a good return but remain at a very competitive level.

So, in short, there is no recommendation as to which is better, the travel agency site or the airline site. It really is a case of who comes up best on the day. It is definitely worth doing your due diligence.

So we’ve looked timings and the source of the special fares. One more thing that is worth considering is the routing of your flight. You will these days have seen that modern airliners are breaking all sorts of records in long-haul non-stop flights such as Perth to London, Singapore to New York, Auckland to Dubai. The list goes on. Yes, these can save a lot of time and if time is a concern then these are a great solution.  If however, time is not so important and you don’t mind spending a few extra hours getting there, then check out services that do have stop-overs along the way.  For example, I used to travel to Europe from Sydney fairly regularly and I would choose to fly a carrier via Dubai. I had the option of the Sydney direct to Dubai, changeover and then on to London. Instead, I chose the option that touched down in Bangkok for an hour or so on its way to Dubai. It took a couple of extra hours but I enjoyed a cheaper fare, as it was less popular with those in a mad rush, and I had the opportunity to stretch my legs and get some real air along the way.  It comes down to personal preference but there are opportunities to save.

I hope this has been some help. By all means, we would be happy to hear your ideas on how to save on your travel spend.

Flight mode, why do we need to use this when we fly?

Flight or Airplane Mode

Air travel is something that a great many of us get to do reasonably frequently.  For some, it is too often, for others it is not often enough. Whichever it is, we are all familiar with the various announcements that are made on-board, particularly this one…

“At this time, make sure your seat backs and tray tables are in their full upright position and that your seat belt is correctly fastened. Also, your portable electronic devices must be set to ‘airplane’ mode until an announcement is made upon arrival. Thank you.”

Game controller flying your plane.
Your new pilot, the kid with the game controller.

Most of us dutifully obey the instruction and reach for our device(s) switching them either off, or to the particular phone makers version of Flight or Airplane mode. It wasn’t so many years ago that the devices had to be turned off completely from the moment you arrived at your seat until such time as the aircraft reached a certain altitude. We were led to believe that our mobile devices would interfere with the aircraft’s systems and it was very much in our own interests to keep those devices switched off. I always used to have visions of some 10-year-old kid in row 36 who managed to get his game controller linked to the flight controls and then take us through some barrel rolls and loop de loops.

Things have changed a little now. Your mobile phone can be left on, with most airlines, for the whole flight and the only concession you have to make is to ensure it is in Flight Mode for the duration of the trip. This is of course only for devices weighing under 1Kg. Not because they emit a stronger signal or anything, but because they can become seriously dangerous projectiles in the event of the aircraft performing extreme manoeuvres.  So you will be asked to stow those during take off and landing.

…because they can become seriously dangerous projectiles in the event of….

Ok, so back to the Flight Mode question. Why do we still need to use flight mode during the course of the flight? Various sources indicate that the effect of a mobile phone or cell phone on an aircraft’s flight instruments is fairly negligible. Aircraft instrumentation is state of the art as you would expect from a unit costing tens if not hundreds of millions. There are so many systems with many kilometres of wiring throughout the aircraft that need protecting from each other, never mind your mobile device. These systems are fully shielded so that attenuation or interference from outside sources cannot corrupt signals sent around the systems.

So does that mean we can go ahead and just ignore the request for flight mode from the crew then?  Not quite. There is still a relatively old technology used by the flight crew. The radio. No, not the one tuned to the football, but the one used in the all-important communications with air traffic control. The giving and receiving of instructions is still done using the good old radio waves.  Mobile devices depend on microwave towers or other ground stations to provide them with the required signal to enable them to provide you with information and other services you depend on. As you can imagine, these towers get harder and hard to find as you are cruising 11 kilometres up, perhaps over sea or desert.  Your phone, being the faithful servant that it is, tries harder by cranking up the signal strength to as much as 8 watts in an effort to enable you to view those all-important food and puppy shots.

So what, I hear you say. Well, cast your mind back to the days when mobile/cell phones switched from analogue to digital signal. When you got your new digital-enabled phone, you found the signal and call quality was nice and crisp. However, if you were ever on a call near someone with an analogue phone, you knew all about it.  It sounded like your ear was being ripped apart. This is what it can be like for the pilots, maybe not quite as extreme, but an annoyance never the less.

Let’s face it, if the use of mobile/cell phones was of major concern to flight safety then you can rest assured that leaving the responsibility of ensuring the devices were turned off would not be left to the travelling public.  There is no doubt that on every flight you will find a number of devices have been left on during a flight either due to forgetfulness or laziness.

Whether it is safety critical or not, we want our pilots to be as relaxed as possible. We want them to be able hear and be heard when they talk to the ground without the possibility of interference blurring any flight direction instructions.  So complying with the flight mode instruction still carries as much weight as it ever did.

What Does Flight Mode Do?

Flight mode on your cell or mobile.
The control centre on your mobile or cell phone.

The flight mode function on your phone or other radio-equipped device is the main control switch to turn off all radio enabled functions on your device. On your typical mobile/cell phone, this includes the voice/text, data (3g, 4g etc), Bluetooth and Wifi. You also have GPS but this doesn’t actually send anything, it sits there and listens for satellite signals and then translates them into something you understand by showing it on a map. Without data, however, you won’t get your map presentation so having GPS can be as useful as an ashtray on a motorbike.

For a few years now several airlines have been trialing and are supplying Wifi onboard their aircraft. What this means is that you have the ability now to connect to the aircraft’s onboard Wifi service and enjoy surfing the net and checking your email in the same way you can do at an internet cafe. “So hang on”, I hear you say, “I had to put my phone in Flight Mode, so how can I connect using Wifi?” Very good question and by the way, bravo for putting your phone in flight mode. As I said, Flight Mode is a master switch for turning off all radio related functions on your cell, mobile, tablet or laptop. Once they are all off you can turn individual functions back on. So seat belts on, Flight Mode on and then wait for the announcement that Wifi service has commenced and turn just Wifi on.

The Wifi signal is much weaker than your main mobile or cell call signal as it only needs to talk to a device mere metres from your seat to get a connection. This is not going to scream in the pilot’s ear so everyone is happy.

Personally, I have mixed feelings about on-board Wifi. I’ve always seen flying as a few hours you can step off the planet and leave yours and responsibilities behind with a good excuse for doing so. You know what I mean, let them miss you a little. Now I’m sure that corporate travellers will be expected to connect up and be available online or get that project completed because all resources are available. No peace for the wicked.

Flight Mode as we have seen is not going to make or break your flight as far as we can tell, but let’s show some consideration for the pilots who have to talk over the interference. Your phone charge will last a lot longer in Flight Mode, so everybody is happy.

Fly safely and LIKE us if you do.


Aircraft Noise

A380 on approach to Heathrow Airport

The emotive topic of aircraft noise.

Aircraft noise can be a very emotional subject for those who are affected by it in their day to day lives. Yes, like other aircraft enthusiasts, I love being next to an airport taking in the sights and thrilling at the gut-shaking sounds of powerful jets. However,  I have also lived with those same jets passing near my home. The disruptive effect on your day to day life cannot be overstated.  Not being able to speak to someone else in the room or listen to your favourite TV show gets very frustrating. In the 1980s I lived in Fulham, London.  Twice every evening our windows literally rattled as first the Concorde from New York arrived followed sometime later by the one from Washington DC. Thrilling at first, but it gets old rather quickly.

So what is being done about it? What is the solution?

Aircraft noise in most countries is taken very seriously. Its disruptive characteristics have a negative effect on those exposed to it at close hand. Loss of quality of life, loss of productivity by those who have disturbed sleep among other things.

Enter the Jeg Age.

In the early days of passenger air travel, piston driven propellor engines were the only form of propulsion. Whilst they were relatively noisy, they didn’t produce sounds in the high-frequency range that jets do.  When the jet age began with aircraft like the Boeing 707 and the Douglas DC8, a whole new ball game started. These early jets, compared with today, were fuel hungry and extremely noisy. Their engines were what you call pure jets, consisting solely of the jet engine turbine. The result was that the high pressure ignited fuel-air mixture was forced out of the tailpipe into still air. The friction caused between the fast travelling air meeting the still air was significant and caused a large amount of the roaring sound that resulted.

Aircraft and particularly engine makers have for decades been working diligently to find ways to reduce the sound footprint of a jet engine. The most significant breakthrough was the bypass engine. The concept is to take the aforementioned pure jet, the jet turbine, and encase it in a second nacelle. The nacelle is the outer casing of the engine. Inside the front of this nacelle is a large fan. This fan sucks in air from the front of the engine and feeds some of it into the jet engine turbine, the rest of it flows around the jet turbine and is ejected back around the flow coming out of the exhaust tailpipe of the jet turbine.  As well as adding to the thrust of the engine, the bypass airflow also serves to encapsulate the exhaust from the jet turbine. This serves to reduce the friction between the jet turbine exhaust and the still air, as well as dampening the sound.

New methods and materials used in the construction of engine nacelles and the engines themselves have also been instrumental in reducing jet engine noise. Boeing for example have

Boeing 737-9 MAX CFM LEAP-1B
Boeing 737-9 MAX CFM LEAP-1B engine. The chevroned rear of the nacelle like the Boeing 787 ensures a smooth laminar airflow over the engine casing.

adopted a new configuration for the trailing edge of their engine nacelles which can be seen on the Boeing 787,  Boeing 747 8  and the new 737 Max aircraft models. The nacelle trailing edge is finished in a chevron configuration, like a sawtooth. This means there is a longer linear trailing edge which allows the air from the engine and the still surrounding air to merge together over a larger area, spreading that shock over a larger amount of air particles. The smoother the transition through the air of an aircraft, the greater its fuel economy and the less noise it makes.

Aircraft design improvements around noise reduction are not just limited to creating quieter engines. When Airbus Industrie began their initial design of the giant A380, one of the design requirements was to make it as quiet as possible. The engines, of course, were designed to be state of the art and provide noise reduction to strict specifications. Airbus, however, also looked at another factor. An aircraft has a much larger noise footprint when it flys close to the ground. That stands to reason, an aircraft flying low over your house makes much more noise than one flying twice as high. So what Airbus undertook to do was to design the aircraft so that it was capable of a steeper climb out. That is to say that the A380 is designed to be able to climb more steeply after take-off, thereby spending less time closer to the ground while departing a city.

Flying Quieter

It is not only what you are flying in that makes a difference. Airports located near built-up areas are continually being pressured to find ways to reduce their noise footprint. As our urban areas continue to sprawl, airports that may once have been located in the countryside now find themselves being surrounded by new housing and industry. It is tempting to think, well they knew the airport was there already so how can they complain? The truth of the matter is, many of our cities are getting overcrowded and whatever land is available must be used.

As our cities get bigger and spread around airport areas, more people are finding themselves living with aircraft noise. Of course airports provide cities with the lifeblood of their economies. Having an airport near the centres of business encourages compnies to base themselves in those cities.China Airlines Airbus A330-300 (B-18303) on final approach into Taipei Songshan Airport.
As our cities get bigger and spread around airport areas, more people are finding themselves living with aircraft noise. Of course, airports provide cities with the lifeblood of their economies. Having an airport near the centres of business encourages companies to base themselves in those cities.

Many airports have adopted various noise abatement procedures to help reduce the noise impact of their operations. For example, they can adopt air traffic control procedures that vary the approach paths to the airport. That way fewer aircraft will fly over more suburbs rather than a few suburbs bearing the full brunt. Aircraft can be guided over water or forested areas as much as possible. During off-peak times secondary runways can be used to allow those living under the main runway(s) approach path to have a break.

The way aircraft are controlled in the landing phase can also make a difference. In the landing phase, most aircraft generate a significant amount of noise due to the configuration of flaps and additional engine thrust required to compensate for the extra drag caused by the extension of flaps. Traditionally most approach patterns for landing at an airport have consisted of stepping the aircraft down to lower altitudes as it gets closer to the airfield. For example, it gets cleared down to 10,000 feet where it flies for a while, then down to 5,000 feet where once again it flies for a while.

Continuous descent approach CDA
The Continuous Descent Approach ensures that the landing aircraft stays as high above the ground as possible during the whole landing approach phase. Thereby it minimises the noise footprint over populated areas it passes over by being higher above them.

During this time it is overflying populated areas at these relatively low altitudes generating noise. A new approach, literally, is the constant glideslope. This means the aircraft is not asked to start descent until it is clear all the way to the runway. It means the aircraft will descend at a constant rate all the way to the ground and not spend any time flying over the ground at lower altitudes waiting to get further clearance to descend. Like the A380s take-off above, the aircraft will spend the minimum amount of time close to the ground where it is the noisiest.

Curfew is an option adopted by many airports. This restricts the operations of jet aircraft to certain hours of the day. For example, there may be no jet operations permitted between 10 pm and 6 am. This ensures that there is a quiet time when most people are trying to sleep. Curfew can cause problems for airlines. Flight delays for aircraft travelling to the curfew airport can be further exacerbated if that delay means they may arrive after curfew comes into effect. If they were only delayed by an hour to start with, they may find that the curfew will add a further 8 hours to the delay as they need to now arrive after 6 am.

Another scenario affecting airline competitiveness is where we have two airlines, one based in city A where there is a curfew and one in city B where there is no curfew. Both airlines want to maximise the number of flights they can do between cities A and B to profit from carrying more passengers. The airline operating from city B with no curfew has the advantage as they can start operating earlier and finish later.

Airport curfew and airline competitiveness effects.
Here we can see that the airline that operates out of the airport with a 10 pm to 6 am curfew is compromised by having to start later and finish earlier than its competitor based at the non-curfew affected airport. In this comparison, the airline from the non-curfew airport can do 3 return trips against its competitor’s 2.

By leaving at 4 am for example and arriving just after the 6 am curfew the airline from the non-curfew city is already halfway through their first return trip before the airline from the curfew city has even started. Similarly, the non-curfew city airline can depart on their last leg just before 10 pm curfew whilst the curfew city airline needs to conclude their last flight by 10 pm.

Another innovation to make airports quieter is the provision of electrical services for aircraft at the terminal gates. You may have noticed when you are at the airport that even though a jet might be stationary at the gate, you can still hear a jet engine whine. This is caused by what is known as the APU or Auxilary Power Unit. The APU is a small jet engine that usually sits in the tail cone of a jet aircraft. It doesn’t provide any thrust as its sole purpose, as the name implies, is to provide power to the aircraft whilst its main engines are not running. This power is what is used to run lighting, air conditioning and other electrical functions whilst the aircraft is parked. The APU may be much smaller than the main engines, however, its noise output is still significant. If you live next to an airport the jet noise is constant. To alleviate this type of noise, many airports are providing land-based power which an aircraft can plug into instead of firing up their noisy APUs before shutting down main engines. A significant amount of noise is avoided as well as unnecessary pollution.

Friendly Neighbour

It is accepted that airports are not the best of neighbours. Some airports, however,  make an effort to try and make life better for those who live close.  I use an example from Sydney, Australia, which is the largest city in Australia and a very important commercial hub. Sydney’s Kingsford Smith International airport is located around 7 kilometres from the city centre which is handy for travellers but also ensures many parts of the city are exposed to aircraft noise. Sydney city undertook to compensate the worst affected suburbs by providing the homes with soundproof double glazed windows. This, of course, helped those residents immensely, but at what cost?  Well, subscribing to the concept of user pays the users of the noisy aircraft paid. A levy of A$3.60 was applied to each ticket that involved an arrival or departure in Sydney. Once the expense of the double glazing was covered the levy was removed.

It is doubtful we will ever completely resolve the issue of aircraft noise, but finding ways to reduce it and manage it better goes a long way to improving the lives of those who are subjected to it. Finding ways to observe noise abatement helps us all.

Boeing 797 a Middle of Market Solution

MoM 797 Boeing

The use of the 797 designation could be a nice round off for a 60-year cycle since the introduction of the Boeing 707. But why do we need another Boeing model and what is Middle of the Market?

Middle of the Market(MoM) is a term Boeing coined back in 2005 which described their then MoM solutions, the Boeing 757 at the top end of the single-aisle market and the Boeing 767 at the bottom end of the twin-aisle market. Those two venerable workhorses have been out of production for some time now which is why Boeing is concerned about this sector of the market.

So where does Middle of the Market lie? One could be forgiven for thinking that the 737 is growing bigger in the form of the 737 MAX and there is a smaller 787, the 787-8. However, let’s take a closer look at how those two aircraft compare.

Aircraft  Max Take-off Weight  Range  Configuration  Passengers
Boeing 737 MAX-9 88,300 Kg (194,700 lb) 6,510 km (3,515 nmi) 2 Class 178
Boeing 787-8 227,900 Kg (502,500 lb) 13,621 km (7,355 nmi) 2 Class 335
 Gap  139,600Kg (307,800 lb) 7,111 Km (3,840 nmi)  – 157

Looking at the figures above you can get an appreciation for the large gap between the largest 737 and the smallest 787.  To service this section of the market, airlines have to either underutilise their 787s or schedule more frequent services with their 737s. Neither option is very financially desirable which is why Boeing is looking at a completely new design for this niche in the market.

Sources indicate, and Boeing themselves have made announcements at the last Paris Airshow, that they expect to begin design work on what has unofficially been named the Boeing 797 or the MoM in 2018. The expected Entry Into Service (EIS) is 2024-2025 however, some sources indicate this could slip to 2026.

So what will the anticipated new model be like?

Boeing 737-8 MAX Winglet
This view shows the distinctive Boeing 737 MAX winglet. Two smaller winglets mean that there is less weight required than for a more robust single longer span. In addition, it means that a significant addition wing surface is added whilst still being able to fit into Gate size C at airport terminals. Will we see this design feature included in the Boeing 797 design

General design requirements call for an aircraft that can manage a range up to 9,630 Km (5,200 nmi), around 10 hours flying. This will enable the aircraft to be used on routes such as the North Atlantic where it would be small enough to operate into and out of smaller city airports, avoiding the traditionally overcrowded main hubs. For passengers, the benefit will be to be able to fly to far off destinations from their home airport without inconvenient connections along the way.

The carrying capacity will, of course, depend on the carrier’s choice of configuration of the passenger cabin. The passenger carrying range is targeted for 220 – 270.

The new design will require a new range of engine with thrust in the 45,000-50,000 lbs range. Boeing has specified a requirement for a geared turbofan. This is where a gearbox sits between the big fan at the front of the engine and the internal turbine. This enables greater control over the engine with the ability to maximise the efficiency of engine speeds at different stages of flight. CFM, which is 50% co-owned by G.E. and Safran, have indicated they will be competing with Rolls Royce to produce such an engine, whilst Pratt and Whitney will offer an upgraded version of their GTF engine.

Boeing is confident in this sector of the market and estimates that they will be able to sell 4,000 797s over a period of 20 years. Airbus for their part are confident that their current offerings of the Airbus 321 NEO and A330 NEO will cover them, however, they haven’t ruled out the possible addition of an A322 to the Airbus family.
Construction of the B797 is likely to draw on lessons, new techniques and new materials that have gone into the development of the 787 as well as the 737 Max. The wings and fuselage will be made primarily from carbon fibre materials, as is the larger 787. We may also see the split winglets which are a feature of the 737 Max. These will increase the wing lifting area, giving better fuel economy without the penalty of greater wingspan. The benefit of maintaining a lesser wingspan is to enable the aircraft to fit into smaller gate areas at smaller airports thus enabling the concept of flying between more regional centres.

No doubt as design decisions are laid down, we will get a much clearer idea of how the latest Boeing offering will look. Meanwhile, 2026 seems a long way off. To bridge the gap, Boeing is seriously considering reintroducing the 767 300ER as an interim measure. It is a decision that has been on again, off again, but apparently, it is currently in an on again phase. The last off again phase was due to the production of the 787 being lifted from 12 to 14 per month, but we assume this roadblock has been removed.

Let us see what the future brings.

If you know any more about the Boeing 797 or MoM, please feel free to comment below.

Why airplane windows are round

Douglas C-47b G-APBC British Midland

Why are airplane windows rounded?

You may have wondered why airplane windows are round. Yes, it does look sleeker perhaps and gives a streamlined impression. To be honest as far as streamlining goes it matters not whether the windows are square, round or some other shape, as they are flush with the fuselage metal and the air goes past them just as happily. So, is there another reason for rounded windows?

Airliner window showing rounded shape
An airliner window showing rounded shape which we are very familiar with today.

The answer, of course, is yes. Every feature of an aircraft exists for a very specific reason. Designs of various components are normally in place to respond to certain conditions that exist in various phases of flight to which the aircraft will be exposed. These can be anticipated conditions which designers are aware of, or they can be the result of lessons learned in the school of hard knocks.

The design of aircraft windows falls into the school of hard knocks category.

In the early days of aviation when passengers were first being carried, windows were found to be required as people would tend to become quite claustrophobic in a windowless tube. In spite of the weight penalty incurred by adding slabs of perspex at regular intervals along the side of the fuselage, designers resigned themselves to the necessity if they were to carry more than just cargo.

The early airliner windows resembled those you might find on a bus.  They were usually rectangular in shape and came in various sizes depending on who’s aircraft you were in. Passengers would have the opportunity to enjoy the view and assure themselves that they were indeed flying right side up.

This worked like a dream, everyone was happy, passengers enjoyed the flying experience quite happily entering this metal or canvas tube to be taken aloft and deposited at some distant location. This applied to propeller airliners and worked well in their operating range of altitudes to a maximum of the mid 20,000s of feet.

Enter the jet age

Junkers Ju52.3m G-AHOF BEA Ringway.

In the early 1950s, there was a new sound in the sky. Jet engines were used for the first time on passenger transport aircraft. The de Havilland Comet was a radical new concept in passenger travel. With its four jet engines buried in the wing roots, it was a very sleek looking aircraft for the period. The Comet offered faster travel times as compared to its propeller predecessors partly due to its ability to fly higher in thinner air, which propeller engines were not capable of doing.

For a year, the Comet enjoyed huge success. It was popular with passengers as the higher altitude flights meant not only faster travel times but also smoother flying due to the Comet’s ability to fly above most of the turbulent weather, that propeller aircraft were forced to fly through

The cause of these accidents had investigators baffled. With all the pieces of wreckage retrieved, they could ascertain that the aircraft suffered catastrophic structural failure. Eventually, they were able to pinpoint the source of the break up to a point in the roof of the fuselage. It took some time before they finally worked out the root cause.

Effects of high altitude flying.

As mentioned earlier, propeller aircraft are limited to how high they can fly. This means that the effect of high altitude flying is not really a factor in their day to day operation. Let’s look, however, at jet airliners. These aircraft fly much higher, often twice as high as their propeller-driven cousins.

A de-Haviland Comet airliner prototype at Hatfield England. You can notice the very square shape of the windows compared to those we are used to today. This was how it was done on propeller-driven airliners of the past, but was to prove fatal in the jet age.
A de-Haviland Comet airliner prototype at Hatfield England. You can notice the very square shape of the windows compared to those we are used to today. This was how it was done on propeller-driven airliners of the past, but was to prove fatal in the jet age.

We know that we as humans can only survive below a certain altitude if we are not to succumb to the effects of hypoxia. This, in simple terms, means we need to have a certain amount of oxygen in the air we breathe or we will lose consciousness and eventually perish. Airliner manufacturers are aware of this situation and have as a result come up with pressurisation in aircraft cabins when it is anticipated that this aircraft will climb above the acceptable altitude.

In the past, most airliners have offered a cabin pressure which is approximately equivalent to the pressure at 10,000 feet above sea level. In today’s more modern aircraft such as the Airbus A350 or Boeing 787 Dreamliner, the pressure offered is closer to that found at 6,000 feet above sea level.  Obviously the lower the pressure altitude, the more comfortable it is for the passengers as it is closer to what they are used to on the ground.

Today’s aircraft are made from various metal alloys and have a very high strength to weight ratio. This notwithstanding, there is still some anticipated growing and shrinking of the fuselage each time the aircraft climbs and descends. Each takeoff, climb and descent and landing is known as a cycle. Aircraft with very high cycle amounts are those that are used on short domestic hops as opposed to those doing long trans-continental or trans-oceanic flights. These aircraft are rigorously checked for any cracks or metal fatigue resulting from many cycles where the fuselage is subject to many expansion and contraction events.

Before the advent of the jet age, the understanding of the effects of cycles and metal fatigue was not understood as they had not applied to airliners that had been used thus far. It was not until the Comet flew much higher and endured many cycles that things unravelled. The Comet still flew fairly short hops by today’s standards, much like the propeller aircraft of the day. A trip from London to Singapore would involve many stopovers such as; London, Rome, Cairo, Karachi, Calcutta, Rangoon, Singapore. That is 6 cycles for one trip.

Square Windows

As mentioned above, investigators of the Comet crashes were able to pinpoint the source of the structural failure to a point in the fuselage roof. It seemed as if a crack had opened up along one of the joins between pieces of the aluminium skin. After some time and testing, it was found that the crack had started at the corner of one of the windows.

Window section of Fuselage of de Havilland Comet Airliner G-ALYP which was the third Comet built. On 10 January 1954 after taking of from Rome enroute London Heathrow, the aircraft broke up near the island of Elba on the Italian coast.
This is the actual fragment skin that peeled off the de Havilland Comet G-ALYP, retrieved from the ocean floor, that allowed investigators to figure out the flaw that caused several crashes. This changed how jet airliners were made forever.

The Comet was designed with square windows just like its propeller-driven ancestors. Unlike its propeller-driven ancestors, the Comet experienced a much more extreme difference in pressures as it flew much higher. Tests showed that structural pressures would always find the weakest point, which in this case was the corner of a square window. Instead of pressure being absorbed evenly throughout the structure it found the window corner was the weakest point which became the focus of the pressure.

Dan-Air London Comet G-AYWX
Dan-Air London Comet G-AYWX. The de Havilland Comet with rounded windows continued on to a successful 30 years of service. Here we see the larger Comet 4C model which included round windows and wing pods for additional fuel.

The Comet was grounded for two years while the research was conducted and corrections were made to the design. Whilst the Comet mark one never flew again and sales were severely affected for the following versions, it still went on to have a successful 30 years of life with rounded windows.

So why do we have rounded windows on aircraft? It is to maintain structural integrity and distribution of the considerable forces applied to the fuselage evenly.

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