Emergency Landing Systems and Procedures

Types of Aviation Emergencies

Aviation emergencies range from precautionary situations requiring early landing to immediate threats requiring immediate action. ICAO and regulatory authorities classify them:

• MAYDAY: An imminent, grave threat to the aircraft or occupants. Declared on radio by repeating "MAYDAY MAYDAY MAYDAY." Air traffic control clears all traffic from the vicinity, declares an airport emergency, and dispatches ARFF (Aircraft Rescue and Fire Fighting) services.
• PAN-PAN: An urgent situation requiring assistance, but not immediately life-threatening. Used for medical emergencies, a sick passenger, or a precautionary return to land.
• Squawk 7700: Setting transponder code 7700 silently alerts ATC to an emergency, appearing instantly on radar displays across the region.

The Decision Process

Pilots use a structured decision-making framework during emergencies. For most abnormal situations, the sequence is: Aviate (fly the airplane), Navigate (determine where to go), Communicate (advise ATC and cabin crew). The priority is always aircraft control first — more accidents have been caused by pilots focusing on troubleshooting while allowing the aircraft to enter an unsafe flight condition than by flying while evaluating the problem.

The decision on whether to divert, return to departure airport, or continue to destination depends on the nature of the problem, fuel state, weather at alternates, and proximity of suitable airports. For a contained engine failure with no other anomalies, continuation to destination is often the safest choice (more landing practice, better weather, familiar airport).

Emergency Checklists

Every abnormal and emergency situation is covered by manufacturer-provided checklists, carried in the aircraft and loaded into the Electronic Flight Bag (EFB). Emergency Memory Items — the most time-critical steps that must be performed immediately from memory — are limited in number and trained to automaticity. After memory items are complete, crews retrieve and run the printed checklist to ensure no step is missed.

The philosophy of "dark and quiet" cockpit management means pilots systematically silence warnings, identify the cause, and address it methodically rather than reacting impulsively. Modern aircraft Emergency/Abnormal procedures are developed collaboratively between manufacturers, airlines, and regulators after extensive human factors analysis.

Evacuation Slides

Every emergency exit on a commercial airliner is equipped with an automatically-deploying evacuation slide or slide-raft. Slides inflate in under 6 seconds using compressed nitrogen and CO2. The certification standard requires that all passengers and crew be evacuated through half the available exits in under 90 seconds — demonstrated using real volunteers in darkness with some exits blocked.

Slide/raft combinations on over-water aircraft double as life rafts after detachment. They carry survival equipment, signaling lights, and sea anchors. Passengers must leave all carry-on baggage — a hard-sided case can puncture a slide.

Water Landing Procedures

Successful water landings — ditchings — require aircraft structural integrity at impact and rapid orderly evacuation. The A320 family has been certified for ditching, with a belly-mounted valve that closes to reduce water ingress rate. Life jackets under or in the seat must be donned outside the aircraft (inflating inside creates a flotation obstacle near the ceiling during egress). Flight attendants provide regular safety briefings on life jacket location and donning procedure for this reason.

The "Miracle on the Hudson" (2009) demonstrated that a modern airliner can survive a low-speed water impact with zero fatalities when the aircraft is properly configured and evacuation is conducted orderly. The Airbus A320's fuselage skin and frame structure maintained integrity on the water long enough for all passengers to evacuate onto the wings.

What Passengers Should Do

• Pay attention to safety briefings: The exit nearest you may be behind you; locate it visually.
• Read the safety card: Each aircraft type has different brace positions, exit mechanisms, and life jacket locations.
• Keep seatbelts fastened: The leading cause of in-flight injury is unexpected turbulence while unbelted.
• In an evacuation: Move quickly, leave all baggage, follow crew directions, do not inflate life jacket until outside.
• Brace position: Lean forward, head down, hands over head — proven to reduce head, neck, and torso injuries in survivable impacts.