‘EE bay water ingress may’ve caused AI 171 crash’: Aviation expert quotes FAA directive; rules out pilot error

Air India plane crash: Aviation expert Richard Godfrey, in an interview with Geoffrey Thomas, has shared the probable root cause behind the Ahmedabad plane crash on June 12. He claimed that the Ram Air Turbine (RAT) on AI 171 deployed automatically before the fuel switch transitioned to “Cutoff”. Not just this, he also ruled out the claims of pilot error, which many thought after reading the paraphrased excerpts from the AAIB preliminary report. The AAIB preliminary report was released a month after the London-bound aircraft crashed and killed all but one passenger on board.

But before diving deep into the analysis, here’s a quick recap of the key findings from the AAIB preliminary report: 

At 1:13 pm, the aircraft requested pushback and startup clearance. AT 1:19:12 pm, the ATC inquired if the pilots would require the full length of Runway 23, to which they confirmed. This followed ATC’s approval for pushback at 1:13:13 pm and startup clearance at 1:16:59 pm.

At 1:25:15 pm, the ATC granted taxi clearance after the cockpit requested. At 1:33:45 pm, AI 171 was instructed to line up on Runway 23 for takeoff. Roughly four minutes later, ATC cleared the flight for takeoff. Just two minutes after lifting off, the pilots issued a MAYDAY call to ATC and crashed seconds later. Due to the extremely short interval between the distress call and the impact, ATC was unable to establish communication.

The report noted that both engines shut down within one second of each other after the fuel supply was cut off, and that relight attempts were made. The engines, recovered from the crash site, were found in the “Run” position. According to the cockpit voice recorder, one pilot can be heard asking the other why he had cut off the engines. The second pilot replied that he had not done so.

With these details in mind, we now turn to the analysis that dismisses pilot error as a factor and identifies the most probable root cause of the crash.

‘RAT was auto-deployed before cut-off’

After going through a large set of data, including a preliminary report and CCTV footage from the airport, Godfrey observed that the RAT was auto-deployed at around 1:38:47 pm. “As per the EAFR data, both engines’ N2 values passed below minimum idle speed, and the RAT hydraulic pump began supplying hydraulic power at about 08:08:47 UTC (1:38:47 pm IST),” the report mentioned. 

Godfrey emphasised that the preliminary report failed to explain when and why the RAT was deployed. However, it does contain an image clearly showing the RAT in its extended position.

“A reasonable assumption would be that the screenshot was taken at 08:08:47 UTC (1:38:47 pm IST). It turns out this assumption is wrong, and the screenshot was taken a bit later. In fact, another 2.5 seconds later, to be precise,” he clarified. 

He reached this conclusion by synchronising multiple datasets – the preliminary report’s FDR and ATC logs (accurate to the nearest second, ±0.5 seconds), FlightRadar24 ADS-B data (precise to the millisecond, ±1 ms), and high-frame-rate airport security CCTV footage recorded at 29.921 frames per second, accurate to within 33 milliseconds.

Godfrey further explained how he mapped the CCTV camera’s field of view from the preliminary report. The location was 229 metres from the Runway 23 end.

“So, it was exactly 2.5 seconds after the RAT hydraulic pump began supplying hydraulic power at 8:08:47 UTC (1:38:47 pm IST), according to the FDR data,” he further said. 

However, going by the report, the engines were transitioned from “Run” to “Cutoff” at about 1:38:42 pm before the RAT began supplying hydraulic power at about 1:38:47 pm. The engines were transitioned from “Cutoff” to “Run” at around 1:38:52 pm. 

RAT provides emergency hydraulic or electrical power during a loss of main power, such as dual‑engine failure. It can deploy automatically or manually, giving pilots enough power to control the aircraft and attempt a safe landing. However, it only supplies essential systems and needs enough speed and altitude to work effectively. If the failure occurs at very low altitude or just after takeoff, the RAT might not generate enough power quickly enough to prevent a crash.

Maintenance issues and non-compliance with FAA guidelines

Godfrey investigated six possible root causes behind the AI 171 crash and listed out the one he thinks is highly likely, followed by the moderate and low ones. He also ruled out two probable causes.

He said that the highly probable cause behind the crash was the water ingress in the Electronic Equipment (EE) bay. This means that the water accidentally entered critical aircraft compartments, areas such as the EE bay or composite material structures, possibly through leaks, cracks, or physical damage.

The aviation expert based this on the recent Airworthiness Directives (ADs) from 2025 that specifically address this issue in Boeing 787 aircraft. The directive warns that installed water line couplings in lavatories or galleys can cause leaks, allowing water to migrate into the EE bay. Once there, the water can trigger electrical failures and potentially lead to a complete loss of power.

The second possible cause Godfrey considered was a shared DC bus failure. While he said that this would have been technically possible, it would require the rare, simultaneous failure of multiple contactors (electrical switches). In aviation, a DC electrical bus acts as a hub which distributes direct current (DC) power from sources like generators, batteries, or transformer-rectifiers. 

Godfrey ranked IPC Faults (breaker trips or electrical arcs) and Software-Controlled Isolation as low-probable causes. The timeline of these events did not match the accident’s timeline, and no historical cases exist for the latter scenario, respectively.

He also dismissed GCU Software Overflow as a possible cause, noting that the aircraft had been powered down within the last 140 days, which is well inside the threshold for this fault to occur. Likewise, he ruled out PRB-A water ingress, clarifying that the supposed Boeing service bulletin is a fake document. 

The above table was shared by the aviation expert.

“The most likely cause of the accident, involving Air India flight 171, was water ingress into the electronic equipment (EE) bay, during rotation and that led to a simultaneous electrical disruption of the EEC and FADEC and the electrical power buses feeding both FADECs and EECs. This resulted in a near instantaneous shutdown of both engines at low air speed and low altitude,” he concluded. 

He went on to say, “Due to the extremely limited energy margin, there was insufficient time for the FADEC-controlled engine relight sequence to restore thrust and to prevent a loss of control and terrain impact. It takes at least 20 seconds, if not longer, for the engine relight sequence.”

No pilot error

He also ruled out the pilot error in the Air India plane crash on June 12. “The root cause was not the pilot error,” he said, before adding, “There may well have been some discussion in the cockpit between the pilots about who did what and when, but it wasn’t the root cause. I think they were taken by surprise. And, this event was preventable.”

“In the cockpit voice recording, one of the pilots is heard asking the other why did he cutoff. The other pilot responded that he did not do so,” the AAIB preliminary report mentioned. 

The flight was commanded by 56-year-old Captain Sumeet Sabharwal, with 32-year-old Clive Kunder as the First Officer. Both of them, together, two aviators had logged over 19,000 flying hours, with almost half of that time spent operating Boeing 787 aircraft. Both had proper rest and cleared health checks before flying the plane.

The aviation expert attributed the tragedy to lapses in maintenance oversight and non-compliance with FAA Airworthiness Directive 2025. This directive, he noted, explicitly warns about water ingress into the EE bay and calls for improvements to the cabin ceiling to prevent such incidents.