Much of the world’s fleet of about 11,000 Airbus A320 series aircraft – the most popular airliner in the world according to sales – are affected by a current emergency airworthiness directive from the European Union Aviation Safety Agency and the US Federal Aviation Administration requiring that operators modify their aircraft control software to make it more resistant to the effects of solar radiation.
This followed a sudden loss of height in the cruise involving a JetBlue A320 en route from Cancun, Mexico to Newark, USA on 30 October. Solar radiation is believed to have been responsible for corrupting the data in one of the aircraft’s flight control computers causing the sudden height loss – which injured several passengers. Recovery action by the pilots ensured the aircraft diverted safely to Tampa, Florida.
Most younger A320s need only a quick software patch to harden the microchip resistance in their flight control computers against particularly vigorous bursts of solar radiation, but nearly a thousand of the oldest aircraft may need to change the units.
Solar radiation is known to be able to interfere with GPS signals, radio communication, inertial navigation systems, autopilot, and full-authority digital engine controls (FADEC), although incidents are rare. A mysterious sudden pitch-down by a Qantas A330 in the cruise over Western Australia in October 2008 is now reckoned to have been caused by corrupted data from an air data inertial reference unit (ADIRU) that may have been subject to solar radiation damage.
All aircraft are more vulnerable than suface vehicles to solar radiation effects because, at high altitude, there is less atmospheric attenuation of the sun’s electromagnetic energy. Polar flights are particularly vulnerable because the earth’s magnetic field provides less shielding and the troposphere is at a lower altitude there.
A320 series aircraft have three three flight control primary computers (FCPC), two flight control secondary computers (FCSC), and a flight augmentation computer, all of which provide considerable systems redundancy, plus a cross-checking capability to detect and correct anomalous data.
The UK Civil Aviation Authority said today that there had been virtually no disruption to flight schedules because airlines were so quick to apply software fixes.
1 December 2025: a statement from Airbus on this date claimed that only about 100 A320 series aircraft remained to receive the softwear hardening required by EASA an the FAA.
The movement of two small switches on the aft end of the flight deck centre console, reachable easily by both pilots, appears to hold the key to what happened to the Air India Boeing 787-8 that crashed fatally just after take-off at Ahmedabad on 12 June.
It seems that one of the pilots selected these switches from “Run” to “Cut Off”, stopping the engines at a critical point just after the aircraft became airborne. The purpose of this article is to examine the arguments for and against deliberate action (compared with unintentional error) on the part of one of the Air India pilots.
On 11 July the Indian Air Accident Investigation Bureau published its preliminary factual report on Air India Flight AI171, a Boeing 787-8 registration VT-ANB. This has revealed the movement of the fuel control switches (FCS) mentioned above, and the resulting consequences of that movement. The data confirming this was derived from the two Enhanced Airborne Flight Recorders (EAFR) in the accident aircraft.
There are two FCSs, one for each engine in a 787. They have two settings: Cut Off and Run. The first act by any crew in starting a 787’s engines on the ground is to set the switches to Run. On the ground or in the air, setting the switches to Cut Off stops the fuel flow to the engines. (See photograph below, showing the switches just behind and below the engine power levers)
According to the AAIB report, just after take-off at Ahmedabad, these switches were moved from Run (up position) to Cut Off (down position). The left switch was moved first then, one second later, the right switch. This action cut off the fuel flow to both engines. There is no automatic function that could move these switches, so they must have been moved manually, or by something physically impacting them. Each switch has a locking mechanism so it cannot be moved accidentally, and there are guard brackets either side of the pair to deflect inadvertent contact by objects. To select the switches from one setting to the other, they must first be pulled out against a spring force to release a locking mechanism, then moved up or down.
Timeline (UTC):
08:07:37VT-ANB begins take-off roll. 08:08:39Lift-off at 155kt. 08:08:42Max airspeed achieved180kt, also No. 1 FCS switch was moved from Run to Cut Off, followed by the FCS for engine No. 2.08:08:47the Ram Air Turbine began supplying hydraulic power. 08:08:52No 1 engine FCS moved from Cut Off to Run. 08:08:56No 2 engine FCS moved from Cut Off to Run. 08:09:05Mayday call transmitted. 08:09:11EAFR recording stopped.
The report says: “In the cockpit voice recording, one of the pilots is heard asking the other why did he cutoff [sic]. The other pilot responded that he did not do so.” Each pilot is recorded on a separate channel, so the AAIB must know which pilot made each statement, but has decided not to release the information at this preliminary stage, The report confirms that the copilot was the pilot flying, the captain the pilot monitoring. So it seems that one of them, apparently, moved both FCS from Run to Cut Off (see Timeline above), and the other noticed him doing it. Then, about 10 seconds later, one of the pilots attempted to restart the engines by restoring both FCSs to Run.
The report explains the effect of restoring the FCSs to Run, first in 787s generally, then specifically what happened in this case: “When fuel control switches are moved from CUTOFF to RUN while the aircraft is inflight, each engines full authority dual engine control (FADEC) automatically manages a relight and thrust recovery sequence of ignition and fuel introduction. The EGT [exhaust gas temperature in VT-ANB] was observed to be rising for both engines indicating relight. Engine 1’s core deceleration stopped, reversed and started to progress to recovery. Engine 2 was able to relight but could not arrest core speed deceleration and re-introduced fuel repeatedly to increase core speed acceleration and recovery. The EAFR recording stopped at 08:09:11 UTC.”
Take-off and early climb is a period of intense concentration by both pilots, the joint task being to ensure the aircraft maintains a steady climb while allowing the airspeed to increase gradually in a controlled way.
Under normal circumstances, after unstick there is only one actionable task for the pilots to carry out quickly: to check that a positive rate of climb is confirmed by the flight instruments, then select the undercarriage up. This task is normally carried out by the pilot monitoring on orders from the pilot flying, and it would entail moving the undercarriage control lever – located on the forward instrument panel – manually upward. In this case, according to the report, no-one called for the gear to be retracted, and no-one selected it up.
Instead, at about the time the gear would normally have been retracted, the FCS were moved downward from Run to Cut Off, the left switch first, the right switch a second later.
It is difficult to imagine that a crew member would have made such a gross error as reaching down and slightly back to move two small switches downward, one after the other, as a substitute action for a well established routine which would have involved reaching forward to move a single lever upward. And there was no cueing request from the pilot flying to pull the gear up anyway.
Pilots have occasionally, however, carried out inadvertent gross errors that almost defy credibility. You can see here the description of how, in January 2023, a Yeti Airlines ATR72 scheduled passenger flight was inadvertently set up for disaster during a visual circling approach to land at Pokhara airport, Nepal. I wrote that linked piece based on the preliminary report, but when the final report was published by the Nepal authorities it gave the following verdict: “The most probable cause of the accident is determined to be the inadvertent movement of both condition levers to the feathered position in flight, which resulted in feathering of both propellers and subsequent loss of thrust, leading to an aerodynamic stall and collision with terrain.” The check pilot had been asked by the pilot flying to increase the flap setting from 15deg to 30deg, but instead of moving the flap lever, he moved the pair of engine condition levers (picture supplied in linked article) to the position that demands the propellers to feather and stop turning.
If one of the pilots of AI171 did know what he was doing when he moved the FCS, he must have known that his action would have more or less guaranteed the result the world has witnessed, because there was insufficient time to restore usable power once it had been cut. VT-ANB was airborne only 3 seconds before the first FCS was switched to Cut Off, followed a second later by the second FCS, then ten seconds after that the FCS were both switched back to Run. The total airborne time was 42 seconds before colliding with the buildings that began break-up of the aircraft.
As for the likelihood that professional pilots would want to cause the destruction of the aeroplane they are flying, history provides evidence that it happens from time to time.
This was the summary of the situation as presented in the FlightGlobal annual safety review for calendar year 2023, which points out that deliberate acts by pilots to bring down airliners have been carried out by aircrew from all regions and cultures: “Pilot suicide on commercial flights in the last three decades has not involved only Europeans and North Americans. A Japanese, a Moroccan, an Egyptian, a Mozambican, a Botswanan, and a Singaporean, among others, have all been involved. The Flight Safety Foundation’s Aviation Safety Network accident database shows that, in its records beginning the 1950s, there has been a marked acceleration in the numbers of flights brought down by pilot suicide since the beginning of the 1990s, and this acceleration has continued in the new century. It is undoubtedly a modern flight safety hazard.” Since that time, although China has not confirmed it, the rest of the world has reason to believe that the March 2022 loss of a China Eastern Airlines Boeing 737 was not an accident.
It is inevitable that deliberate action by flight crew should be considered when a disaster like AI171 occurs. The India Air Accident Investigation Bureau will undoubtely investigate this possibility. But just one part of the trajedy is that, when all the flight crew die, their intentions will never be known for certain.
Air India flight 171 crashed immediately after take-off from Ahmedabad on 12 June, and today, two weeks later, with no news about causes, the system is beginning to leak.
This is what happens naturally when information which people know is available to the authorities is withheld from the media and the public.
It’s easy for authorities like the Indian Directorate General of Civil Aviation to believe they can justify withholding information on the grounds that it’s very complicated, and they intend to release it quite soon anyway. Unfortunately for the DGCA, today’s media environment does not have that kind of patience any longer, especially in a case like this.
This fatal accident, a first for the Boeing 787 of any marque, killed 241 people on board and many on the ground. Whatever the cause was, it was highly unusual – maybe unique. For that reason, the industry and its regulators are desperate to know if there might be an unknown latent failure in the 787, so they can stop it happening again.
This pressure is what causes the system to leak. The Air India 171 flight data recorder has been downloaded by the National Transportation Safety Board for the DGCA at the Air Accident Investigation Bureau in Delhi, so some outstanding data will already be clear, even if not fully analysed yet.
Meanwhile the NTSB is sworn to secrecy according to the International Civil Aviation Organisation protocol which states that the nation in which the accident occured is responsible for the investigation. So in this case, the NTSB provides all its data to the DGCA, but as an agency of the nation in which the accident aircraft was designed, built and certificated, the NTSB has a particular responsibility to ensure that all operators of Boeing 787s throughout the world – there are about 1,000 of the type flying today – learn as fast as possible what, if anything, they should do.
That NTSB responsibility is a heavy one, but at the same time they want, if possible, to stick to the protocols to ensure the investigation proceeds calmly.
The NTSB obviously has to tell Boeing any details that are emerging. Then Boeing has an urgent duty to provide advice to 787 operators, particularly if any system failure detected might possibly repeat. This information will be received at Boeing by many engineers and technicians who must act rapidly to frame a plan for inspections and corrective action, then communicate with the operators, where an even larger group of airline technicians must carry out the Boeing advisories, or any directives that the Federal Aviation Administration may see fit to issue.
The pressure on the DGCA is of a different kind, and arguably less urgent. It is, after all, a regulator, a bureaucracy, with the responsibility to oversee the investigation and ensure it is conducted properly and according to law. It does, however, face the reality that a lot of highly relevant information is being shared right now by hundreds of experts all over the world, and the media knows it. So if the DGCA delays release of established facts, it will face increasing censure, especially if it delays release beyond one calendar month from the date of the accident.
A month is now firmly established as the time it should take for an air accident investigator to establish the basic facts of the case, and release a “preliminary factual report”. The final report can take more than a year.
Meanwhile, what of all those FDR facts whizzing around the world between experts at the manufacturer, the investigator, the world’s civil aviation authorities, and all the airlines that operate 787s? Well, they leak, of course, because they are important and everyone knows it. But most of the time the precise source of emerging information isn’t obvious, because individuals discussing them do not want to be recognised, so responsible journalists have to be careful what we do with what we hear.
What happens, however, is that it gradually becomes clear, among the plethora of opinions and guesswork always out there, which facts are beginning to establish themselves.
Some are simple, almost obvious. For example, the one emergency radio call made by the AI 171 crew said they had lost power, and an observation of the flight path almost immediately after unstick corroborates that puzzling fact.
But double engine failure immediately after take-off is almost unheard of, so what caused it? That is less obvious.
The exception to that is the requirement to test the Electronic Engine Control System. These are computers called Full-Authority Digital Engine Controls (FADEC) that monitor the engines’ performance and react to demands by the pilots via the power levers or the flight control panel (autopilot input). These are vital, but have been established since the 1980s as highly dependable devices, and more reliable by far than the old mechanical connections.
So if both FADECs failed that would be extraordinary. In fact it makes more sense that something else failed or malfunctioned and disabled both FADECs. There is a lot of credible information gathering that backs this up, but since its precise source is not certain, I will not run it here.
Suffice to say we will soon learn what the problem was, because the DGCA knows it would look very bad to sit on it beyond 12 July 2025.
Learmount.com 