Darwinian thoughts on airliner species in a pandemic

The Covid-19 pandemic’s dramatic effect on air travel has accelerated aircraft retirements, particularly older long-haul types. This, of course, includes the undisputed Queen of the Skies, the Boeing 747, the withdrawal of which has been the cause of many misty-eyed moments among aviation romantics.

British Airways’ last 747-400, in retro BOAC livery, on its way to retirement

The “other jumbo”, the Airbus A380 was already suffering a crisis of its own before Covid’s arrival, and the pandemic motivated the manufacturer to put the trickling production line out of its misery.

The A380 – technically an excellent, if over-engineered aircraft – was the victim of a miscalculation by Airbus way back in the late 1980s-early 1990s about the shape of future global air transport. The A380 was to replace the 747, but the belief that a replacement would be needed at all was based on an assumption that the industry would continue to develop much as it had in the previous three decades.

Emirates, by far the A380’s biggest user, will certainly be able to continue flying many of them

That didn’t look like a bad decision at the time, but Boeing’s predictions turned out to be far more accurate. The US manufacturer foresaw the diminution of the importance of hub-and-spoke networks feeding the world’s major airports where they sit astride the globe’s air travel arteries – the traditional trunk routes. The A380 was ideal for serving these.

But the American manufacturer’s crystal ball showed smaller widebody twins taking over from thirsty quads, and carrying passengers who wanted it straight past the massive hubs directly to the secondary cities. The 767 was already showing the way in the 1990s, with American carriers on transatlantic routes, but the 777 and 787 extended the possibilities. Darwin had smiled on Boeing.

Although Airbus was also ready for many of these long-haul twin opportunities with its flexible A330 twin series (and now the A350), in the mid-1990s the four-engine A340 had initially become much more popular than Airbus had predicted. Europe, culturally less of a risk-taker than the USA, was not yet ready to fly twins over extended oceanic routes, or over endless Arctic and Siberian wildernesses. In a quad, an engine failure raises the crew’s blood pressure a bit, but they can elect to continue to destination. In a twin, it means an instant diversion.

Meanwhile, across the Atlantic, in July 1995, Boeing and the Federal Aviation Administration were ready to gamble on bringing a brand-new big twin, the 777, into service with pre-cleared permission to fly over oceanic or wilderness regions where the nearest diversion airport could be up to three hours away at single-engine flying speed. That extension from the previous 2h meant there were hardly any routes a twin couldn’t fly. Boeing and its FAA partner went for it; and what’s more they got away with it. A single early-days disaster would have put paid to that policy, but it didn’t happen, and now everyone takes 180min ETOPS (extended twin engine operations) for granted. Darwin had smiled on Boeing once more.

Today, in the pandemic, the Airbus A340 is suffering a fate similar to the 747’s, but there will be fewer tears simply because it could not have achieved the iconic status the 747 had won through its status as the world’s first jumbo jet, its sheer longevity, and its unique shape.

Among today’s widebodies, Darwin will continue to smile on the newer big twins, and the few remaining tri-jets and the older big twins will be parked or converted to freighters before their time would normally be up. Meanwhile, the marketplace that the new big twins have had to themselves for some time is to be invaded by what may turn out to be a particularly timely product: Airbus’ single-aisle venture into long-haul, the A321XLR.

Another anomaly brought by the pandemic is that air cargo has been the saviour of many airlines during the pandemic, because unlike passenger traffic, cargo has hardly been affected. For example, Taiwan’s China Airlines has just announced an operating profit for 2020 on the back of cargo, and recently took delivery of a new 777F.

Short-haul – and thus the single-aisle fleet – has not been hit as hard as long-haul simply because domestic air travel is free of the border restrictions that nation states impose on travellers when they fear the spread of infection from abroad.  But as in their long-haul fleets, airlines are still disposing of the earlier versions of their 737s, A320s and regional aircraft.

Exceptionally on a global scale, the US domestic carriers are forecasting break-even levels of passenger business by June, with strong demand from the leisure travel market, although there is slightly less confidence in a business travel rebound. Domestic carriers elsewhere, in less geographically large countries – particularly those with mature high speed rail networks – will take longer to recover than the likes of American, Delta, United and Southwest, and may not have had the government injection of survival cash the US airlines have had – plus the boost from the fact that the USA has successfully accelerated its Covid vaccination programme. Is that Darwin smiling on America again, or just on big, prosperous nations? He may well be smiling on China too.

No-one can be sure of the post-Covid shape of the world’s commercial air transport industry. Truisms, abound, like the contention that the strongest carriers will survive, and that the pandemic’s result will be further consolidation and fewer airlines. One of the unknowns is whether people’s travelling priorities will have changed, especially in the light of growing concern about climate change. Will long-haul, in particular, be a victim of such a concern?

But at present, whenever there is a hint that lockdown may be eased, people are rushing to book holiday travel. Air travel will indeed survive, the question is: what will it look like?

How to infuriate a traditional Boeing pilot

Today I was replying to a message from a good friend in Maryland, and found that I’d written to him what I have wanted to put up here for a while.

He had picked up on something I wrote in FlightGlobal/Flight International a month or so ago about Boeing CEO Dave Calhoun’s thoughts on the kind of control interface that would be best for pilots flying Boeing’s next clean-sheet-of-paper aeroplane in tomorrow’s skies.

This is what I suggested to him:

“I don’t actually know what Boeing will do with the pilot’s “joystick” or yoke equivalent in its next-generation aircraft. My observation that you picked up on was based entirely on the musings of Boeing’s new boss Dave Calhoun when he suggested they might need to have to do a complete re-think of how to tomorrow’s pilots should interface with tomorrow’s aeroplanes.

The thing about the airline piloting job now is that it has drastically changed. Even aircraft originally designed in the 1960s, like the 737 series, in their latest versions put just as many computers between the pilots and the flying control surfaces as Airbus does with its FBW fleet. So any remaining efforts to fool the pilots into believing that the control feedback they feel is the real thing is just artifice. And like any part of the system, the artificial feedback can fail and thus mislead.

The only aeroplanes in which Bob-Hoover type stick-and-rudder skills were ever really needed is manually controlled aerobatic machines flown in perfect VMC during a display. Modern combat aircraft, built for aerodynamic instability so as to be manoeuvrable, have had FBW sidesticks for decades, and the pilot’s main task is to direct the mission and its defence, not to use finely-honed skills to keep it flying. The stick is just a device for pointing such an aircraft where you want it to go.

In an airliner you were never supposed to handle it as if you were Bob Hoover flying a display. Nowadays, if you have to fly it manually at all – and 99% of the time you are told not to – your job is ABSOLUTELY NOT to fly it by the seat of your pants, it’s to select the attitude/power combination you need to get you elegantly from where you are to where your passengers wish to go. I can tell you from experience, a spring-loaded sidestick is an easier device than a yoke for selecting an attitude, and as for selecting power, throttle levers do the same everywhere, back-driven or not.

So I’d guess Boeing probably will go down that track. Pilots who still need to be flattered by being presented with controls that look like the old fashioned ones but do not work like them are no longer in the right job!”

No pilot/aeroplane interface is perfect. But choosing the best one for the next Boeing is going to be an interesting job for Calhoun.

Airlines: the pre-Truth industry

Airline pilots today are obliged to steer their machines according to an instrument discovered in the earth’s Iron Age: the magnetic compass. Ships’ commanders only use that these days if all else fails.

By modern navigation standards the magnetic compass is not an accurate device. An aviator flying along a magnetic meridian toward either the North or South Magnetic Pole flies “a wiggly track” according to the Geomagnetism Team of the British Geological Survey. The pilot’s magnetic compass may display a constant heading, but the aircraft relying on it follows the gently wandering vagaries of the earth’s dipolar magnetic field.

In 2011 a Boeing 737 suffered a fatal crash on approach to land because of the artificially-induced complexities of a navigation system based on Magnetic North in a digital era (detail later). All four crew and eight of the 11 passengers were killed.

Modern aviation navigation can be conducted using a phenomenally accurate, multi-sensor system orientated to the earth’s spin axis, with reliable integrated backups. But in fact it’s compromised by the decision to continue using a legacy system of orientation based on the earth’s ever-changing magnetic field.

This dependency on steering by the earth’s dipolar magnetic field when technology provides far better alternatives is enforced by institutions like the International Civil Aviation Organisation and the International Air Transport Association which are content with the status quo.

For the time being at least.

ICAO’s maritime sibling, the International Maritime Organisation, approved navigation by True North/South beginning in the late 1970s, and now it is universal for all but a few coastal mariners who choose not to use GPS backed up by inertial navigation systems (INS). Now the IMO is in the final stages of implementing standards for what it calls “e-navigation”, its way of describing the use of the best available integrated digital, satellite and other technology, plus best practice, to achieve the most accurate and reliable navigation at sea, all with the earth’s spin axis as the directional orientation reference.

ICAO itself, on the other hand, commented recently: “This issue [navigation by True North] is not on our work programme at present.”

Asked for a comment on the situation, the UK CAA said: “We understand the issue, and with the increased use of GPS etc., moving to True North does make more sense. Also as more aerodromes look to formalise GNSS (global navigation satellite systems) approaches the logic is clear.”

So why not adopt True North? It’s not the CAA’s job to make this decision (rather it’s for ICAO and EASA), but the CAA slightly apologetically offered this explanation on behalf of the international aviation establishment: “If you were starting from a blank sheet of paper with the technology available today, you would select True North. But aviation started with magnetic from the outset. The infrastructure supporting aviation is also based on magnetic, including VORs, runway directions, approach procedures, radar etc.”

ICAO and IATA argue that navigation by magnetic track still works, so there’s no need to face the effort and cost of moving to an orientation system based on Earth’s spin axis (True North/South) despite the fact that the cost of changeover would be one-off.

Maintaining the existing system, which requires regular updating as the earth’s two magnetic poles constantly migrate relative to the geographic North and South Poles, has a continual cost, but that’s apparently fine because it’s built in to the system’s budget, so no new decisions need to be made.

Magnetic navigation is fine as a backup system – and nobody doubts that every aircraft will continue to carry a standby magnetic compass in the cockpit as long as manned flight lasts. The IMO requires all ships to have a magnetic compass, but to steer by a system using True North.

Maps and charts are oriented according to the earth’s spin axis – True North/South. This is also the orientation datum programmed into the firmware of the aircraft flight management computers (FMC). They have to convert their orientation information to Magnetic to pass it to the avionics displays, unless the pilots choose to select True, which, of course, they can. But air traffic management protocol requires them to use Magnetic when operating under instrument flight rules (IFR).

Air traffic controllers still pass magnetic headings for pilots to steer for procedures and traffic separation purposes. Pilots still navigate by adopting Magnetic headings which are actually converted from True by the FMS and shown on their compasses in the primary flight display/navigation display.

The FMS does this by applying a “variation” between Magnetic and True that was embedded in the firmware when the system was set up.

This variation value needs to be updated regularly, but it rarely is, despite the fact that, in the last 40 years the rate of migration of the Magnetic North Pole (MNP) has accelerated dramatically. FMS software is easily updated, but firmware is more of a problem.

In fact the surface position of the MNP is forecast to reach its closest point relative to the Geographic North Pole (GNP) in 2020 (approximately 87N 170E), and then it will continue moving tangentially past the GNP toward Russia’s north coast. Therefore the so-called magnetic heading most aircraft are flying is inaccurate because the variation value – in many fleets – has not been updated since the FMS was new.


As a result of this built-in disparity, in 2011 an airliner fatally crashed into high ground because the pilots were confused by an inaccurate compass heading.

On 20 August 2011 the crew of the Bradley Air Services Boeing 737-210C (C-GNWN) were attempting an instrument landing system (ILS) approach to the airport at Resolute Bay, Nunavut, in Canada’s far northern islands, somewhat closer to the Magnetic North Pole than most aviators usually get to fly. The airfield and approach charts – and therefore the procedures – show True North for orientation. This is customary in polar regions because the magnetic field lines close to the Magnetic North Pole have a strong vertical component, so the lateral strength of the field reduces. Meanwhile the variation can be enormous.

The Resolute Bay ILS approach that day was to runway 35T, the localiser orientated to 347degT. The magnetic variation at Resolute Bay at the time was 28degW.

The autopilot was initially set to VOR/LOC Capture, and the compass system set to True, but according to the Transportation Safety Board of Canada (TSBC) report there was a compass error. The captain was flying 330degT according to the heading on his horizontal situation indicator (HSI), perceiving the intercept angle to be 17deg from the right of the localiser (347T).

The report explains: “However, due to the compass error, the aircraft’s true heading was 346deg. With 3deg of wind drift to the right, the aircraft diverged further right of the localiser. The crew’s workload increased as they attempted to resolve the ambiguity of the track divergence, which was incongruent with the perceived intercept angle and expected results.”


Diagram from TSBC report

This is what happens when pilots don’t know what to believe, and in a region where there are three Norths – Magnetic, True, and Grid (the latter for local charts), confusion is the default when things don’t proceed as expected.

The crew were indeed confused and decided to abandon the approach, but just as they were initiating the go-around the 737 flew into a snow-covered rocky hilltop about a mile east of the airfield. It didn’t help that the aircraft was fitted with an old fashioned – rather than an enhanced – ground proximity warning system, and that the crew were under additional pressure because they began the descent well above the glideslope.

Spurred by this event, at ICAO’s Air Navigation Conference in November 2012 Nav Canada proposed that aviation should stop using magnetic references and use only directional orientation relative to the Geographic North Pole.

This makes particular sense for any country – like Canada – with territories that approach the arctic or antarctic regions, who are forced to use True close to the magnetic poles, but it would also work perfectly worldwide. But the Montreal-headquartered ICAO has still not put the issue on its “to do” list.

Now, however, with more flights than ever transiting the Arctic ocean on routes between North America and South East Asia or India, steering by Magnetic North makes little sense, although it just happens that the Magnetic North Pole is now migrating closer to the Geographic North Pole than it has ever been in recorded history.

That imminent closeness of the two North Poles is used by the pro-True lobby to suggest this is a natural time to change, because the changes required will be the smallest they have ever been. But it is change itself that presents the one-off cost, and which demands scarce human resources to organise it, not the mathematical size of the variation between Magnetic and True.

The following rather simplified chart shows that the advantages – in today’s world – of Magnetic are few, and the disadvantages many and compelling, while the advantages of True are powerful and its disadvantages relatively trivial.


Maybe at present there is no actual urgency to adopt True North as aviation’s navigation lodestar, but industry voices on the subject are muted, as if it is bad form to step out of line.

A major European airline, not alone in its beliefs, has a compelling and detailed presentation on the subject, in which it concludes : “Transition from magnetic to true reference is unavoidable. The transition phase will need further studies in order to maintain the safety objectives. Time is ripe to start the transition process.” But the carrier was not prepared to break cover.