AI171 crash probe exposes limits of aviation's gentlemanly protocols

One year after Air India Flight AI171 crashed shortly after take-off from Ahmedabad, killing 260 people, the Aircraft Accident Investigation Bureau (AAIB) asked the country to trust its investigation.

In a statement marking the anniversary, the AAIB expressed condolences, reaffirmed its commitment to a "thorough, independent, objective and evidence-based investigation", noted that "significant progress" had been made, and said the evidence collected was still being analysed.

Also read: Exclusive | Did Boeing’s machine fail in Air India 171 crash? A chilling sequence of possibilities

As mentioned in Part 1, in an affidavit before the Supreme Court recently, the bureau made a related legal argument. The Court, it said, should not order any parallel investigation. Aircraft accident investigations are governed by ICAO (International Civil Aviation Organization) Annex 13 and India's Aircraft Investigation Rules. The AAIB is the statutory authority entrusted with conducting the investigation. It alone has custody of the evidence. Its work is proceeding according to internationally accepted procedures.

The legal argument is entirely orthodox. Yet it raises a larger question.

Information versus authority

What obligations accompany exclusive investigative authority in an age when information, expertise and technical scrutiny are no longer confined to the official investigator? That, rather than the particulars of AI171 alone, may prove to be the more enduring issue. The AI171 debate has exposed an increasingly visible tension between a 20th-century system of accident investigation and a 21st-century world of distributed knowledge.

The global aviation investigation framework is built around ICAO Annex 13, one of the cornerstones of modern aviation safety. Its philosophy is admirable. Accident investigations are not intended to apportion blame. Their purpose is to identify causes, learn lessons and prevent recurrence. Investigations should be independent, evidence-based and insulated from political pressure, commercial interests and media speculation.

The role of the official investigator is changing. It is becoming the institution responsible for evaluating competing bodies of evidence and demonstrating, through rigorous analysis, why some explanations are accepted while others are rejected.

To achieve that objective, the framework centralises authority. There is one lead investigator. Accredited participants contribute. Others defer. Public commentary is discouraged. Findings emerge only after careful technical analysis.

For decades, this model worked remarkably well.

But Annex 13 emerged in a world where information itself was scarce. Aircraft did not continuously generate streams of digital operational data. Manufacturers did not monitor fleets through sophisticated global operations centres. Airlines did not maintain vast repositories of aircraft health information. Independent analysts did not have access to satellite imagery, leaked maintenance documents, telemetry logs or global online communities of engineers and pilots.

In that world, the official accident investigator genuinely possessed unique access to information.

Today, that assumption no longer holds.

The digital trails

Modern commercial aircraft generate extraordinary volumes of digital evidence. Aircraft Communications Addressing and Reporting System (ACARS) messages, aircraft health-monitoring systems, engine diagnostics, maintenance analytics and operational records create digital trails that may become available to airlines, manufacturers, engine makers and service providers almost immediately after an occurrence.

Also read: Exclusive | AI-171 crash triggered by fuel switches or engine failure?

This does not mean that any one of these institutions necessarily knows why an aircraft crashed.

Establishing causation remains one of the most demanding tasks in engineering. Critical evidence still comes from cockpit voice recordings, flight data recorders, wreckage examinations, laboratory testing and human-factor analysis.

But it is equally true that many institutions today possess significant parts of the puzzle long before the public sees anything. Boeing possesses design knowledge that no one else does. Engine manufacturers understand their own systems in extraordinary detail. Airlines hold maintenance histories, operational records and health-monitoring information. Investigators remain uniquely positioned to integrate all these strands into a coherent explanation, but they no longer enjoy a monopoly over information itself.

That creates a governance paradox.

The institutions closest to important parts of the evidence are often constrained from speaking publicly. Boeing, General Electric, the US National Transportation Safety Board and others routinely refer inquiries back to the lead investigator. Journalists, victims' families and independent researchers encounter the same response: the investigation is ongoing.

Also read: 6 reasons why India’s probe on Ahmedabad AI-171 crash is raising global alarm

The rationale is understandable. Nobody wants competing narratives, selective leaks or public relations campaigns masquerading as accident investigations. But what happens when the lead investigator itself says very little?

The result is a peculiar form of institutional silence.

Those who possess relevant pieces of the puzzle do not speak because protocol discourages them from doing so. The institution authorised to speak speaks sparingly because the investigation is ongoing.

The public is left with an information vacuum.

What the affidavit shows

The AAIB's own affidavit before the Supreme Court illustrates this asymmetry. It devotes considerable attention to explaining why courts should defer to the official investigation and why Annex 13 protects the independence of investigators. It catalogues broad categories of investigative activity—flight recorder analysis, component examinations, engine testing, witness interviews and organisational review.

But it says comparatively little about how competing technical hypotheses have been evaluated, whether technically credible material originating outside official channels has been considered, or how public criticisms of the preliminary report have been addressed.

Its argument is essentially institutional: the investigation should be trusted because it is being conducted by the institution designated by law and international convention.

The AI171 case illustrates why that may no longer be enough. Over the past year, journalists, aviation safety advocates, pilots' organisations and independent experts have advanced competing hypotheses about the accident. Some have raised questions about aircraft systems. Others have focused on maintenance histories, operational decisions or human factors.

Whether these hypotheses ultimately prove right or wrong is not the point.

A credible investigation need not publicly debate every theory that appears online. But where technically credible alternative explanations acquire substantial public attention, confidence is strengthened when investigators can demonstrate that those possibilities have been examined and explain, at least in broad terms, why they remain under consideration or have been ruled out.

Confidence must be earned

Such engagement would not weaken investigative independence. It would reinforce it. Trust in accident investigations rests not only upon technical competence but also upon public confidence. Transparency does not require investigators to release every piece of evidence or conduct investigations through press conferences. But neither can it consist merely of asking the public to wait indefinitely for a final report.

This becomes particularly important when powerful commercial interests are involved. The modern aviation ecosystem is deeply interconnected. Manufacturers, airlines, regulators, maintenance providers, insurers and governments often have longstanding commercial, regulatory and strategic relationships with one another. That does not imply that investigations are compromised. But it does mean that public confidence cannot simply be presumed.

Confidence must be earned.

The recent history of aviation offers an important lesson. The Boeing 737 MAX investigations initially unfolded within a narrative that focused heavily on pilot actions, pilot training and operational issues. Only as investigations deepened did a broader picture emerge—one that revealed profound problems in aircraft design, certification practices and regulatory oversight.

Also read: AI-171 crash: Pilot’s father seeks SC probe

The lesson was not that investigators acted in bad faith. It was that institutional consensus, particularly during the early stages of a technically complex investigation, is not a substitute for continuing scrutiny.

The same principle applies today.

Questions about AI171 should not be dismissed merely because they originate outside official channels. Independent engineers, pilots, journalists and whistleblowers have repeatedly played important roles in identifying aviation safety problems that formal institutions either overlooked or addressed only after sustained external scrutiny.

Aviation's extraordinary safety record was not built through institutional deference alone. It was built through constant questioning, challenge and learning.

That is why the real issue raised by AI171 extends well beyond a single accident.

It concerns whether the governance model underpinning aviation investigations remains fully adapted to the digital age. Annex 13 was built upon an implicit assumption that information and authority resided in the same institution. Today they do not.

Annex 13 emerged in a world where information itself was scarce. Aircraft did not continuously generate streams of digital operational data. The official accident investigator genuinely possessed unique access to information. That assumption no longer holds.

Information has become distributed across manufacturers, airlines, regulators, investigators, maintenance organisations, engineers, journalists, whistleblowers and independent researchers.

Authority, however, remains concentrated in a single official investigator.

The investigator no longer enjoys a monopoly over information. Nor, increasingly, over investigation itself. Independent journalists investigate. Pilots' associations investigate. Safety organisations investigate. Engineers reconstruct events. Victims' families commission technical analysis. None possesses legal authority. Yet all contribute to the production of knowledge. The role of the official investigator is therefore changing. Increasingly, it is no longer the sole discoverer of truth. It is becoming the institution responsible for evaluating competing bodies of evidence and demonstrating, through rigorous analysis, why some explanations are accepted while others are rejected.

That changes the source of legitimacy. In the twentieth century, legitimacy flowed naturally from privileged access to information. In the twenty-first, it increasingly depends upon visible intellectual rigour.

Also read: AI-171 crash: Pilots’ body sends legal notice to AAIB for summoning captain’s kin

None of this requires abandoning Annex 13. The alternative is certainly not trial by media. But neither should aviation's safety culture become a culture of excessive secrecy.

Exclusive investigative authority carries corresponding obligations—not merely to investigate independently, but to demonstrate, as the investigation progresses, that every materially plausible line of inquiry has been systematically considered.

The families of those who died on AI171 deserve more than condolences and assurances of progress. They deserve a clearer explanation of what investigators know, what they do not yet know, and what remains to be established.

So does the travelling public.

The purpose of accident investigation is not merely to determine what happened. It is to sustain confidence that the truth, wherever it leads, will be pursued without fear, favour or institutional complacency.

More than a year after AI171, the question is no longer only what caused the crash.

It is whether a governance framework built for an age of information scarcity can continue to rely on institutional deference in an age of distributed technical knowledge. Information has become distributed. Authority has not.

The legitimacy of aviation accident investigation will increasingly depend on how successfully those two realities are reconciled.

You can read the first part here