Preliminary report into Air India crash released

Original Article ↗ Hacker News Discussion ↗

Key facts from the preliminary report

  • Shortly after liftoff the 787 reached ~180 kt; both engine fuel control switches transitioned from RUN to CUTOFF about 1 second apart.
  • About 10 seconds later both switches were returned to RUN and both engines began relight, but there was insufficient altitude and time to recover before impact.
  • CVR summary says one pilot asked the other why he had “cut off”; the other denied doing so. Exact wording and tone are not published.

Was it deliberate, mistaken, or mechanical?

  • Many commenters consider intentional action (murder‑suicide) the most parsimonious explanation:
    • Switches are large, guarded, spring‑loaded, and normally require a deliberate pull‑and‑flip action.
    • Both moved within roughly one second, then were consciously moved back.
    • No airworthiness directives have been issued that would suggest a systemic hardware or software risk.
  • Others argue it’s premature to assign intent:
    • Possibilities raised include: mis‑installed or defective locking mechanisms; wiring faults; logic glitches between cockpit switch and FADEC; or extreme “muscle memory” error (confusing shutdown actions normally done at the gate).
    • Avherald and others note a 2018 SAIB about similar fuel switch locking issues; Air India reportedly did not perform the recommended (non‑mandatory) inspection.
    • Some point to an FAA bulletin about an engine control microprocessor (MN4) solder failure that can cause loss of thrust control, though applying this directly here is disputed.

Feasibility of recovery

  • Pilots and sim demonstrations emphasize dual engine loss just after takeoff is essentially unrecoverable: very low altitude, high drag (gear and flaps), and turbine relight times on the order of tens of seconds.
  • Even with quick diagnosis and correct action, the aircraft had only seconds of usable energy.

Design and automation debates

  • Proposals discussed:
    • Software delay or inhibition of dual cutoff for a brief window after liftoff.
    • Interlock between thrust lever position and cutoff switches.
    • Stronger mechanical guards or relocation of cutoffs.
  • Counter‑arguments: adding logic can delay needed shutdown for fires or failures, create new failure modes, and break the “change something, see effect immediately” principle.

Evidence gaps and data recording

  • Lack of cockpit video is widely criticized; unions oppose it over privacy and misuse concerns, while others argue it would quickly resolve questions like this.
  • Several stress this is a preliminary report: full CVR transcript, hardware forensics, and pilot background analysis may still change conclusions.