Unlawful Interference (Hijack)

Unlawful interference (hijack) is an armed or violent takeover of the aircraft by third parties. The most dangerous scenario for crew and passengers.

Source: ICAO Annex 17 Security; ICAO Annex 10 Volume II; ICAO Doc 8973 Security Manual.

Squawk code: 7500

7500 is the international code for unlawful interference / hijack.

ATC sees: "Unlawful Interference" on radar.
Military reaction possible (interception).
Set discreetly if hijacker doesn't notice.

Radio behaviour in hijack

When possible (discreet)

Squawk 7500.
Mayday call carefully: "Mayday Mayday Mayday, DEMRA, unlawful interference" — brief and secretive.
Possibly code word pre-arranged with crew.

When not possible

Try in background to transmit.
Disguise radio broadcast with standard phrases (e.g. "checking frequency").

When hijacker notices

Cooperation aids survival: no open confrontation.
Keep radio contact when possible.
Comply with hijacker's instructions as far as safety permits.

ATC response

Immediate escalation to security authorities.
Military interception possibly initiated.
Preparation for landing at a specific aerodrome.
Other traffic rerouted away from hijack flight.

Arrival on the ground

Pilot stops at an isolated position of the aerodrome (hijack apron).
Authorities take over: SWAT, police, special units.
Hostage negotiation possible.
Crew: calm, cooperative, transparent communication.

Famous hijacking incidents

Classic cases (with impact on aviation security):

9/11 terror attacks (2001): 4 hijacked aircraft in USA — massive security reform worldwide.
Pan Am 103 (1988): Lockerbie bombing over Scotland.
TWA 847 (1985): Beirut hijacking.
Lufthansa 181 "Landshut" (1977): Mogadishu, GSG-9 rescue.
Air France 8969 (1994): Marseille, GIGN rescue.

Source: ICAO Acts of Unlawful Interference database.

Post-9/11 security reforms

Massive tightenings:

Cockpit doors reinforced (locked-door policy).
Air marshals on board (USA, Israel, others).
TSA screening in USA.
No-fly lists.
Sky marshal programmes EU.
Guarded refuelling.

Pilot training for hijack

ICAO Annex 17 recommends:

Anti-hijack training for all pilots.
Cockpit procedure during hijack.
Cockpit-lock procedure before each flight (airline traffic).
Code words with cabin crew.

Third-country risks

Some countries are higher hijack/terror targets:

Conflict zones.
Politically unstable regions.
Third countries with high diaspora-conflict tension.

Before flight to such regions: check State Department / foreign ministry travel advisories.

Cyber hijacking

Modern risk: cyber attacks on avionics (FBW hacking, GPS spoofing).

Boeing 737 MAX: MCAS software issues (not cyber but shows vulnerability).
Aviation cyber security is increasingly important.

Summary

Hijack is the worst cockpit confrontation:

Squawk 7500 as discreetly as possible.
Cooperation with hijacker.
Discreet radio contact when possible.
Trust in authorities' ground response.

Cross-reference

Subject 010: security provisions, NCO.GEN.140 for dangerous goods.