Alerting Service and Search and Rescue

An aircraft that crashes in a remote area, ditches or simply fails to arrive needs someone on the ground to notice and to start looking. That job belongs to the alerting service, the air traffic service that raises the alarm, and to the search and rescue (SAR) organisation that it alerts. The two are defined in different ICAO Annexes, the alerting service in Annex 11 and SAR in Annex 12, but they work as a single chain: an ATS unit notices that something is wrong, grades its concern through three emergency phases, and passes the case to a rescue coordination centre, which sends aircraft, helicopters and ships.

For the pilot, the subject has two sides. The first is avoiding false alarms, above all by closing flight plans. The second is knowing what to do on the other side of an accident, as a survivor laying out signals or as a crew arriving first on the scene. Distress beacons and radio calls, the other ways of starting the chain, are covered in emergency beacons and search and rescue signals and distress and urgency communications.

The alerting service

The alerting service is provided:

• to all aircraft provided with air traffic control service;
• as far as practicable, to all other aircraft that have filed a flight plan or are otherwise known to air traffic services;
• to any aircraft known or believed to be the subject of unlawful interference.

It is available throughout every flight information region, including uncontrolled Class G airspace, where it and flight information service are the only services given (see air traffic services). The flight information centre or area control centre serves as the central point for collecting information about an aircraft in a state of emergency in its FIR and forwarding it to the rescue coordination centre. Other units report to it: if an aircraft that has been handed over to the aerodrome controller fails to land within 5 minutes of its expected landing time and contact with it cannot be re-established, the tower reports this at once to the ACC or FIC, and the alert phase is declared.

Uncertainty, alert and distress phases

The alerting service grades an emergency in three emergency phases, each with a code word used in ATS messages. In increasing order of seriousness they are INCERFA, ALERFA and DETRESFA.

The uncertainty phase is not declared when there is no doubt about the safety of the aircraft and its occupants. The phases need not follow one another: a report that an aircraft is making a forced landing leads straight to the distress phase, and a hijacking to the alert phase. When a phase is declared, the ATS unit notifies the rescue coordination centre and passes on the information it holds about the flight.

Overdue aircraft action

Most alerting cases start with an aircraft that is simply late, and most of those end with an aircraft found safe on the ground. Overdue action is the sequence of checks that follows: the ATS units try to call the aircraft and make enquiries to other relevant sources. At an aerodrome without air traffic control, an AFIS officer also alerts the rescue services and starts overdue action when an expected aircraft does not arrive.

The flight plan is the key. Under SERA.4020, an arrival report must be made at the earliest possible moment after landing for any flight for which a flight plan covering the whole flight was submitted. Where there is no ATS unit at the arrival aerodrome, the pilot makes it as soon as practicable, by the quickest means available, to the nearest ATS unit, giving the aircraft identification, the departure and arrival aerodromes and the time of arrival. In France a flight plan can be closed by telephone, for example to the regional information office (BRIA). Item 19 of the ICAO flight plan, which gives endurance, persons on board, emergency radio, survival equipment, dinghies and the aircraft's colour, is not transmitted with the plan but kept for exactly this case.

In the United States, a VFR flight plan is not closed by a tower; the pilot must close it with Flight Service after landing. If it is not closed within 30 minutes of the ETA, Flight Service begins its search procedure, first with an information request (INREQ) and then with an alert notice (ALNOT). Flight service stations provide search and rescue services and assistance to lost aircraft and aircraft in emergency.

SAR organisation under Annex 12

ICAO Annex 12, Search and Rescue, requires each State to provide SAR services in its territory on a 24-hour basis, and to assist aircraft in distress and survivors of aircraft accidents regardless of their nationality. Each State publishes its SAR arrangements in its AIP, normally in section GEN 3.6.

The service is organised by search and rescue regions (SRR). States delineate them so that they do not overlap, and their boundaries should, as far as practicable, coincide with those of the corresponding flight information regions. The match means that the ACC or FIC declaring an emergency phase normally deals with a single rescue coordination centre.

Rescue centres and on-scene command

A rescue coordination centre (RCC) is the unit responsible for promoting the efficient organisation of the SAR service and for coordinating SAR operations within a search and rescue region. Each State establishes one in each SRR. Where it improves efficiency, a rescue sub-centre (RSC) can be set up under it to cover part of the region. The RCC receives alerts from ATS and from the Cospas-Sarsat beacon system, plans the search and tasks the rescue units.

At the scene, command must be clear. If the first aircraft to reach the scene of an accident is not a SAR aircraft, its pilot-in-command takes charge of the on-scene activities of all aircraft arriving later, until the first dedicated SAR aircraft reaches the scene. If that pilot cannot communicate with the RCC, he or she may hand over, by mutual agreement, to an aircraft that can. With three aircraft, the first on scene without contact with the RCC, the second with good communications and the third a SAR aircraft, command passes from the first to the second by agreement and to the third when it arrives. The on-scene frequency is 123.1 MHz, alongside the emergency frequency 121.5 MHz.

Ground-air visual signal code

Survivors without a radio can talk to search aircraft with the ground-air visual signal code:

The symbols should be at least 2.5 m (8 ft) long and made as conspicuous as possible, in any form that contrasts with the surface, such as trampled snow, oil on sand or burned grass. Size and contrast matter more than neatness: smaller marks are effectively invisible from search height.

Air-to-ground acknowledgement

A search aircraft that has understood a ground signal says so with air-to-ground acknowledgement signals:

• by day, by rocking its wings;
• by night, by flashing its landing lights on and off twice, or, if it has none, its navigation lights.

There is no separate "not understood" signal in the current Annex 12: the absence of the acknowledgement tells the survivors that the message has not been understood. Rocking the wings is also the daytime acknowledgement of tower light signals, which gives pilots one gesture to remember.

Directing a surface craft

A ship or boat is often the fastest way to reach survivors at sea, but aircraft rarely carry marine radios. ICAO gives a visual procedure for directing a surface craft to the scene. The aircraft:

1. circles the surface craft;
2. crosses its projected course close ahead at low altitude, rocking its wings;
3. heads in the direction in which the craft is to go.

Crossing low astern of the craft, rocking the wings, means the opposite: its assistance is no longer required. Aircraft do not normally carry the VHF FM radios used at sea, so talking to a vessel usually means relaying through a coastguard or coastal radio station.

Droppable supplies colour code

Supplies dropped to survivors are packed in containers with coloured streamers, so that their contents are clear without opening them. The SAR droppable supplies colour code is:

The survival equipment an aircraft carries, and its use after a forced landing or ditching, is covered in forced landing and ditching.

Library articles are written for study and exam preparation. They do not replace your aircraft's approved documentation, your operator's procedures or the regulations themselves.