Air India’s hush-hush Dreamliner groundings hint at deeper safety flaw | Exclusive

The story so far

In Part 1 and Part 2 of The Federal’s investigative reports, we looked at how core network degradation on the Air India AI 171 could’ve caused the failure of multiple components that led to the deadly Ahmedabad air crash on June 12, 2025, which killed 241 people on board and 19 people on the ground.

In part 3, we look at how Air India could be facing a fleetwide issue with its Boeing Dreamliners.

The Federal has exclusive evidence that the carrier has grounded as many as three Dreamliners even as, globally, the 787-8 has seen six incidents with as many planes since the Ahmedabad crash. The Federal also has breaking news that the AI 171 reported faults in its powerlines 15 minutes before takeoff at 13.23 PM IST, which could've resulted in early RAT deployment. Because if RAT is deployed before the engines shut down, it's an indicator of existing electrical defects on the plane and pilot innocence.

Extended inspections

Air India quietly grounded three Boeing 787-8 Dreamliners — two overseas and one in India — for extended inspection in the weeks after the deadly Ahmedabad crash that killed 260 people — 241 on board and 19 on ground on June 12.

The silent grounding of three long-haul jets at specialist heavy-maintenance hubs preceded the statements made by Air India CEO Campbell Wilson at the Aviation India 2025 event on October 29 in Delhi. Citing the Aircraft Accident Investigation Bureau’s (AAIB) interim report, he said: “There was nothing wrong with the aircraft’s operations or practices that required changing.”

But, these groundings did not happen in a vacuum. On October 9, Air India’s AI 154 on the Vienna-Delhi route was diverted to Dubai after multiple auto-flight and autopilot failures mid-air.

Six incidents in six months

The Dubai landing in October, along with the fatal AI 171, now brings the tally to four serious in-flight technical events involving Air India’s Boeing 787 Dreamliners.

The first came barely a week after the AI 171 crash — when an AI 310 en route from Hong Kong to Delhi returned to its departure airport due to a technical snag. Then, on October 4, an AI 117, flying Amritsar-Birmingham, experienced an uncommanded RAT (ram air turbine) deployment at around 1,600 feet on approach.

Part 1: Do Lion Air, Air India 171 crashes flag Boeing design flaw?

Part 2: Did Boeing’s machine fail in Air India 171 crash? A chilling sequence of possibilities

And, other airlines have also seen issues with their Dreamliners since the crash. For example, on July 31, a LATAM Airlines flight LA 603, flying Los Angeles to Santiago, suffered electrical problems leading to an uncommanded RAT deployment shortly after take-off. On July 25, a United Airlines flight UA 108, flying Washington Dulles to Munich, reported an in-flight engine shutdown.

Worrying trend

Boeing itself, in a statement last month, said there had been 31 incidents of uncommanded RAT deployment in Dreamliners since the line's launch. What’s emerging now is a worrying trend: the electrical fragility seen on VT-ANB (AI 171) is not limited to that one aircraft. These are alarm bells raising doubts that this may be a fleet-wide Dreamliner vulnerability within Air India.

Three silent groundings. Three different MRO hubs. One uncomfortable pattern.

In recent months, different Maintenance, Repair and Overhaul (MROs) facilities globally have been witnesses to the downtime Air India flights are seeing.

Serious implications

Significantly, Air India has grounded three Boeing 787s but is silent on what issues these planes are facing. The first aircraft, VT-ANA, was grounded in Amman, Jordan, from August 5 to October 11, 2025, at Joramco, one of the Middle East’s largest independent wide-body heavy-maintenance facilities.

Experts say the Dreamliner being parked in Jordan has serious implications as Air India sends planes there for only long-duration structural inspections, heavy checks and modification work.

A second Dreamliner, VT-ANE, was at Etihad Engineering’s wide-body MRO complex in Abu Dhabi, which specialises in composite structural repair and heavy checks, from July 15 to September 24. And a third, VT-ANG, has been parked at the Mumbai MRO since July 25, undergoing extended troubleshooting for recurring technical issues.

Post crash checks

“All three of these Dreamliners entered service around 2012-13. The VT-ANA was a star — it was the very first Dreamliner in Air India's fleet, which started operations in November 2012,” a flight engineer who wishes to remain anonymous told The Federal.

“The VT-ANE started mid-2013 and VT-ANG late 2013. Typically, the first heavy structural check cycle on a 787 should occur between years six and 10, which means it should’ve happened between 2019 and 2023 for this cohort. Instead, Air India is clustering multiple multi-month heavy checks now, in 2025, right after AI 171 (crash)" he added.

He further said this doesn't seem to be normal staggered fleet maintenance planning, but more like "concentrated reliability intervention." He added, “Also, there is a huge cost to planes having long periods of downtime. Airlines would be losing money hand over fist.”

Also read | What India, and the world, can learn from AI-171 Dreamliner crash report

“There's the possibility that these maintenance checks could be routine, because even if there's a scheduled check every 6-10 years, airlines can get a waiver to do it later. We need to know what exactly the faults are for which they've been grounded to figure out what's happened," said Sam Thomas, president of the Indian Pilots Association.

Platform-wide vulnerability?

But maintenance engineers are pushing back, saying that in this subfleet of the 787-8 series, Air India has 26 planes in the VT-ANA to VT-ANZ registrations. For a long-haul subfleet, having three Dreamliners tied up at heavy MRO bases — and two more offline — is a bit unusual. They say this doesn’t look like normal staggered maintenance planning, but more like a concentrated reliability intervention.

And Air India CEO Campbell must have been well aware of these groundings and also the preflight technical issues on the fatal VT-ANB plane.

Pilots and engineering staff The Federal spoke to say there is a real possibility that there’s a platform-wide systems vulnerability, given Air India has quietly pulled three Boeing 787 Dreamliners offline for deep inspection. They say it increasingly looks less like isolated bad luck and more like a repeatable failure mode that demands transparency from both Boeing and regulators like the US Federal Aviation Administration (FAA) and Directorate General of Civil Aviation (DGCA India). News reports say Air India is planning a refurbishment of 26 Boeing 787-8s by 2027.

Planes for retrofit

Per FlightRadar, an online aviation tracker, two other aircraft, VT-ANT and VT-ANP, haven’t flown in recent weeks. They seem to have flown into Boeing’s MRO in Victorville, California, on October 1 and 29, respectively.

Engineers say these two moves are in line with Air India's announced retrofit programme for the 787-8 aircraft at Boeing's Victorville facility. This is a planned $400 million retrofit of all 26 Boeing 787-8 Dreamliners at Boeing’s Victorville facility, aiming to complete the upgrades by mid-2027.

When the RAT comes out uninvited

CCTV footage published in the AAIB report shows the deployment of the RAT seconds after AI 171’s take off. Now, the RAT is a small emergency windmill that drops out of the belly of the jet to generate backup power and is primarily supposed to deploy when main engine-driven electrical power fails.

But in just four months, there have been three uncommanded RAT deployments on Boeing 787s — one fatal and two non-fatal. The first was Air India AI 171, and the other was LATAM LA 603 Los Angeles-Santiago, and the third, Air India AI 117 Amritsar-Birmingham.

Aviation regulator DGCA has since launched a detailed investigation into the recurring “uncommanded” RAT deployments on 787s. Boeing now has admitted to the DGCA that it had observed a similar pattern in as many as 31 Dreamliners worldwide, nearly all within six months of RAT maintenance or electrical resets.

What triggers RAT deployment

The company’s official explanation was mechanical: vibrations from landing or rough runways could jostle the hydraulic shuttle valve loose, triggering the RAT to drop unexpectedly.

Boeing pointed to a 2014 design tweak, a new shuttle valve meant to improve hydraulic locking and a 2015 maintenance instruction reminding technicians to hold the stow switch until hydraulic pressure fell below 200 PSI (normal system pressure being 5,000 PSI). Yet, neither Boeing nor its supplier, Collins Aerospace, ever made that modification mandatory. Airlines could choose whether or not to install it.

But flight engineers say there could be another explanation for these sudden RAT deployments. Per Boeing’s own training manuals, the RAT deploys automatically in flight if any of the following occur:

1. Loss of both engines

2. Loss of power to the instrument buses, or

3. Loss of all three hydraulic systems

So, going by Boeing’s literature, RAT shouldn’t deploy except in an emergency, right? On paper, yes. In practice, no.

Because it looks like on the 787’s integrated electrical architecture, an instability in one small electrical channel seems to have the potential to corrupt data and power in other channels, misleading the RAT.

Economical wiring?

Why would Boeing do this? Why build one tightly integrated electrical architecture – instead of keeping flight controls, hydraulics, and power systems more separated like Airbus generally does?

Also read | Ahmedabad crash puts Boeing under lens again over recurring safety issues

In Boeing’s own words, this was done “to reduce the amount of wiring in the airplane and the overall weight of the airplane.” So on a 787, what happens is that the engines’ electrical generators (PMA/VFSGs) generate very high-voltage 235 volt AC power, which then gets stepped down into lower 115-volt and 28-volt lines that can be used safely by systems like flight computers, tiny air data sensors, etc.

In the tail section, this means the stabiliser trim, hydraulic electric pumps, nitrogen generation system (NGS), cabin climate, brakes, displays — all sit on the same data and power backbone i.e. the core network.

A sick shared backbone

On the AI 171, that shared backbone was already sick: there was a CAT C MEL for core network degradation since June 9, and a CAT A MEL on the NGS power/control line since June 10, two days before the crash. (MELs are active faults with which a flight is allowed to fly for a certain period. CAT A, B categorisation decide the risk and the number of days within which it needs to be fixed.)

Now, the 787’s core network connects some 50 systems — including 22 flight-critical systems like central computers, avionics and FADEC and 28 non-critical components like inflight entertainment, printers and communication panels. And in part 1 of our investigation, we went into how the core network’s interconnectedness can make it vulnerable as a single point of failure.

The story gets more murky by the day of the crash flight. The Boeing 787 uses something called the Bus Power Control Units (BPCUs), which are part of the core network. They are essentially the aircraft’s electrical traffic cops — deciding which generator powers which bus, when to switch or isolate a bus after a surge or fault, and sequencing the system so the aeroplane never ends up in the dark.

Failure in EFBs

According to a Public Interest Litigation (PIL) petition in the Supreme Court, 15 minutes before takeoff at 1:23 PM IST (7.53 UTC), both the left and right BPCU controllers began faulting — which meant the AI 171 could not reliably decide which generator should power which electrical bus — leading to a situation where power can be routed incorrectly, switched at the wrong time, or dropped altogether.

Also read | Understaffed, overworked: India's looming air traffic control crisis

The PIL filed by Capt Amit Singh, a pilot with an international airline, also talks of a failure in the pilots’ flight reference computers or Electronic Flight Bags (EFBs) at the same time.

The EFBs and the flight instruments share the same data and power network on the 787. Now, remember the three conditions under which RAT can get deployed? Loss of engine power, hydraulics or instruments buses.

Emergency power

Given the faults in the BPCU and EFBs, it seems like during the power surge at takeoff, there was a power transient in one of the lines in the aft electrical bay that resulted in RAT deployment on the AI 171. Emergency power was coming on despite both engines generating power.

It was a situation caused by Boeing’s choice to run nearly every major system through a tightly interconnected electrical architecture (the core network), said engineers The Federal spoke to. The aircraft maker did this to save weight and simplify wiring, but it also means a single bad transient anywhere in that network could be interpreted as a loss-of-power event severe enough to trigger RAT deployment, they added.

A reasonable hypothesis given Boeing seems to have had as many as 31 uncommanded RAT deployments since the 787's entry into service, according to the engineers.

The Federal has written to DGCA India, Air India, AAIB, Boeing and received no response at the time of publication.

Pilot error or system failure

Why does RAT deployment matter?

The central debate in the AI 171 crash is whether it is a pilot error or a system failure. It may be recalled that the RAT is the backup emergency turbine. If it had deployed before the fuel cutoff and engine shutdown, then the aircraft was already behaving as if it had lost electrical power before the engines actually failed. Engineers say that points directly to a system failure, not a pilot error.

In an earlier story, we argued that the AAIB’s timestamp for when the RAT began generating hydraulic power indicates that RAT likely deployed before fuel cutoff/engine shutdown. And now, with the evidence submitted before the Supreme Court, there is a strong case that this is what might have happened.

Quoting Boeing literature, the engineers that The Federal spoke to said one of the conditions for RAT to deploy is when the BPCU detects loss of power on the C1/C2 TRU lines that supply the flight-instrument DC buses. (Note: TRU is the unit that converts engine AC power into 28-volt DC power for the flight computers and displays.)

According to the engineers, these C1/C2 TRU lines take power from the engine generators → convert it to 28-volt DC → send it through the forward avionics Remote Power Distribution Unit or RPDU → and from there feed the core avionics racks, flight instruments and the Captain’s EFB. So, when the BPCU and the captain’s EFB faults showed up 15 minutes before takeoff (1:23 PM IST), it means the very same power path needed to keep the instrument buses alive was already unstable before the aircraft even left the ground, the engineers said.

Electrical disturbance theory

According to the AAIB, the single most critical minute was 13:38 IST — in that one minute the aircraft accelerated down the runway, lifted off, lost fuel to the engines, and the crew were already attempting a relight. The Federal now has exclusive evidence, from two sources independent of each other, that at 13:38 IST, there is an ACARS fault code (247450002 597) showing the forward avionics power bus that powers the flight computers and instrument displays was hit — which is exactly the same power path that triggers RAT deployment.

In Part 4, we will go further into these ACARS fault codes and what the AAIB fails to mention.

(Disclaimer: The AAIB has not yet released its final report on the AI 171 crash. All the technical scenarios presented here are based on preliminary information and remain hypotheses. Airlines routinely conduct both scheduled and precautionary checks, especially following major incidents.)