Should The FAA Have Made Its 2018 Safety Bulletin Mandatory? Fuel Switch Warning At Heart of AI-171 Crash Probe

New Delhi: As investigators probe the tragic crash of Air India Flight AI-171, attention is turning to a five-page document quietly issued by the U.S. Federal Aviation Administration (FAA) nearly seven years ago — a Special Airworthiness Information Bulletin (SAIB) that warned of potential malfunctions in fuel control switches used in Boeing aircraft.

That 2018 bulletin — SAIB No. NM-18-33, dated December 17, 2018 — highlighted the risk of fuel control switches being installed with their locking mechanisms disengaged, which could result in inadvertent movement during flight. The concern was based on operator reports from Boeing 737s, but the same switch design (Part No. 4TL837-3D) was also used in Boeing 787-8 aircraft, including the one that crashed in Ahmedabad last month.

Now, in the aftermath of the dual engine failure that brought down AI-171 within seconds of takeoff, aviation safety experts and regulators are asking a difficult question: Should the FAA have gone further and made that bulletin mandatory?

A Switch at the Center of Catastrophe

The preliminary report released by India’s Aircraft Accident Investigation Bureau (AAIB) confirms that both fuel control switches on VT-ANB transitioned from “RUN” to “CUTOFF” mid-air, just three seconds after takeoff. The engines shut down as a result, and the aircraft never recovered. The report notes a chilling cockpit exchange in which one pilot asks, “Why did you cutoff?” — to which the other replies, “I didn’t.”

Investigators believe the switches may have moved inadvertently or due to mechanical failure, precisely the kind of risk the 2018 FAA bulletin sought to highlight.

However, because the SAIB was advisory in nature and not an Airworthiness Directive (AD), airlines were not obligated to take corrective action or perform inspections. Air India did not conduct any inspections related to the SAIB, a decision now under scrutiny.

What the FAA Said in 2018

The SAIB, while not legally binding, carried a strong caution. It stated:

“Operators have reported that some fuel control switches were installed with the locking feature disengaged. We recommend inspection of the installation and engagement of the locking feature to ensure correct operation.”

The FAA concluded that the issue did not constitute an unsafe condition that would warrant a mandatory directive, but still urged operators to review installation procedures.

At the time, there was no known accident tied to this issue.

Calls for a Reassessment

In light of the AI-171 crash, aviation analysts argue that the FAA should have erred on the side of caution — especially because fuel control switches regulate engine shutdowns, and are not protected by software interlocks or dual-confirmation mechanisms.

“When a single movement can kill both engines, you cannot treat a locking issue as trivial,” said one U.S.-based former FAA safety engineer, who spoke on condition of anonymity.

“This was a failure of imagination — not recognizing how a design detail could cascade into disaster.”

Broader Regulatory Questions

The FAA’s choice to issue a SAIB rather than an AD reflects a broader debate in global aviation: When does a known issue demand mandatory compliance, especially in a world of complex, high-reliability systems?

Airworthiness Directives are typically issued only when a risk is deemed a clear safety threat, but as the AI-171 case shows, even advisory concerns can turn deadly under the right (or wrong) set of circumstances.

India’s AAIB has so far not issued any safety recommendations, but is expected to revisit the design and maintenance policies surrounding fuel switch assemblies in its final report.

Boeing and FAA Response Awaited

Both Boeing and the FAA are yet to issue statements in response to the preliminary findings. The FAA has previously defended the SAIB system as a way to share non-critical safety insights without overburdening operators.

But with lives lost and international scrutiny growing, the distinction between “advisory” and “mandatory” is now under the spotlight.

If the FAA had issued an Airworthiness Directive instead of an advisory bulletin in 2018, Air India and other operators would have been compelled to inspect or modify the switches. Whether that might have prevented the AI-171 tragedy is still being investigated — but the question is now a live one in safety circles:

Is an advisory enough when the switch in question can bring down an entire aircraft?