Notice to Mariners No. 30 of 1947

Marine Department,
Wellington, N.Z., 18th August, 1947.

AIR SEA RESCUE

THE following notice, M. 300, issued by the Minister of Transport, London, is republished herewith for general information.

NOTICE TO SHIPOWNERS AND MASTERS

1. In view of the great increase in the employment of aircraft over the sea, the following arrangements have been made to render assistance to aircraft in distress and to ensure the rescue of passengers and crew of aircraft casualties at sea.

2. As Masters are already aware, every Master, on receiving information of distress at sea from any source (including aircraft in distress at sea) is required to render assistance to every person who is in danger of being lost, unless the Master is unable, or in the special circumstances of the case, considers it unreasonable or unnecessary to do so or unless he is released from his obligation by the fact that another ship has undertaken this duty or he receives information that his assistance is no longer required.

3. All information concerning aircraft in distress at sea is passed to the R.A.F. Rescue Control Centre in whose area of responsibility the casualty has occurred or is likely to occur. Aircraft will then be sent, if necessary and practicable, to search for and fix as accurately as possible the position of the casualty. Such aircraft will carry equipment for dropping to survivors. Reliance for rescue will be placed upon naval and merchant ships and on lifeboats of the R.N.L.I. When rescue is unlikely to be effected within a reasonable time by such means, aircraft carrying an airborne lifeboat will be sent. It should be appreciated that the range of the airborne lifeboat as a surface craft is limited and that there may be injured survivors. The assistance of a merchant or other ship may therefore still be required to effect the final rescue.

4. The assistance that can be given to aircraft in distress may be limited in practice by the short time which aircraft normally remain afloat. For this reason it is important that Masters of ships within a reasonable distance of an aircraft in distress should proceed with the greatest possible speed to her assistance.

5. Every endeavour will be made to give merchant ships an accurate position of an aircraft casualty, dinghy, or airborne lifeboat. An aircraft will, if practicable, be kept over survivors at least during daylight hours, until rescue is effected. Unless firm communication has been established with a merchant ship within reasonable distance of the position of the casualty additional assistance from the rescue agencies mentioned in paragraph 3 will always be sought.

6. When given such a fix the ship should at once consult any other ships in the neighbourhood on the best procedure to be adopted, as is the practice in the case of casualties to merchant ships, and a decision should be reached as quickly as possible as to which ship, if any, can best render assistance. The ship proceeding to the casualty should answer the Station sending the broadcast, giving its identity, position, and intended action.

7. Merchant ships will ordinarily be informed of casualties to aircraft by wireless from a Shore Station, or from a search or rescue aircraft. They may, however, pick up S.O.S. messages from aircraft in distress, in which case they should act as in 6 above and also relay the messages to the nearest Shore Station.

8. Where a merchant ship has received an S.O.S. message direct from an aircraft in distress and is proceeding towards the casualty, a bearing should be taken on the transmission, and a message sent by the merchant ship to the Shore Station or other vessels in the vicinity giving the call-signal of the distressed aircraft and the time at which the distress message was received, followed by the bearing and time at which the signal ceased.

9. Merchant ships may receive information of distress in any of the following ways:-

A. By W/T on the international distress frequency from--

(i) A distressed aircraft still in flight (see Appendix A for the form of such message);
(ii) Survivors after casualty has occurred by hand-operated emergency radio transmitter (see Appendix B for form of message);
(iii) A shore wireless station (see Appendix C for form of message;
(iv) A search aircraft (see Appendix D).

B. By visual signals from--

(i) A distressed aircraft;

Apart from other obvious signs, an aircraft may indicate it is in distress by firing a succession of red pyrotechnical lights. Navigation markers dropped by aircraft at sea, emitting smoke or flame and smoke, should not be mistaken for distress signals. Low flying is not in itself an indication of distress. Aircraft in distress which are forced to alight in the sea are instructed to do so ahead and on the lee of a ship.

(ii) A search aircraft--by signalling lamp using the international procedure and plain language;

If the aircraft wishes to guide the ship to the position of the casualty or survivors it will fly low round the ship. It may fire a succession of green pyrotechnical lights or make a series of green flashes. It will then fly off in the direction in which the ship is to be led. British pilots are instructed to rock their aircraft laterally when flying off in the direction of the casualty. The ship should acknowledge receipt of this signal and of any signal under (ii) above by a succession of "T's" in Morse code, or by day, by hoisting the answering signal consisting of a pennant with alternate red and white vertical stripes.

(iii) Survivors in the sea, in an aircraft rubber dinghy or air-borne lifeboat. Such signals may consist of any of the following:-

1. Firing pyrotechnical signals emitting one or more red stars.
2. Flashing a heliograph.
3. Flashing S.O.S. or other distinctive signal by hand torch or other signalling lamp.
4. Flying the international distress signal consisting of a flag with a ball, or anything resembling a ball, above or below it.
5. Flying the aircraft dinghy distress flag consisting of a red pennant with a white circular patch.
6. Blowing of whistles.
7. Lighting small flares giving a greenish light, lasting for about four seconds.
8. Using fluorescene dye marker giving an extensive bright green colour to the sea around the survivors.
9. A dinghy may also be located by yellow kite being flown to support the aerial for the emergency radio transmitter.

APPENDIX A

Form of Distress Calls and Messages from Military Aircraft on 500 kc/s.

1. The exact form of W/T distress call or message from an aircraft in flight will depend on the time available to send it between the onset of the emergency and the landing of the aircraft in the sea. This may be only a matter of seconds.

2. When time permits, a separate distress call and distress message will be sent in the following form:-

(a) Distress Call:

S.O.S. (made three times). Prosign "D.E." Aircraft call sign (made three times). Twenty seconds dash. Prosign "K."

(b) Distress Message:

S.O.S. (made three times). Call sign of any station which answered the distress call (made three times). Prosign "D.E." Aircraft call sign (made three times). Text of message:-

(i) Position and time at position.
(ii) Nature of distress.
(iii) Intention of pilot of aircraft.
(iv) True course of aircraft.
(v) Altitude of aircraft.
(vi) Short weather report including visibility and state of sea. Prosign "K."

3. The above distress call and message may be sent together in the following form:-

(c) Distress Call and Message combined:

S.O.S. (made three times). Prosign "D.E." Aircraft call sign (made three times). Twenty second dash. Text of the message (as in paragraph 2 (b) above). Prosign "K."

APPENDIX B

Form of Distress Message from an Aircraft Dinghy Emergency Transmitter on 500 kc/s.

1. The emergency W/T transmitter is fitted with an automatic keying device to transmit repeatedly one of the following signals:-

(a) SOS followed by a long dash. This will normally be sent.
(b) AA followed by a long dash.

2. Alternatively, the hand keying switch may be used to transmit other messages in Morse code.

APPENDIX C

Form of Aircraft Distress Broadcast by British Shore W/T Station by W/T on 500 kc/s. and by R/T on 1650 kc/s.

1. The international distress frequencies will be used to notify ships at sea of aircraft or personnel in distress. Distress broadcasts will normally be made immediately on receipt of definite distress information and irrespective of other action taken to effect rescue. Once rescue has been effected, the distress broadcasts will be cancelled by the originator.

2. Broadcasts on the distress frequency will be sent out by G.P.O. stations in accordance with the priority borne by the prefix. Transmissions will be made over a period and in accordance with G.P.O. instructions to coast W/T stations. Any acknowledgment received will be passed to the originator.

3. Messages broadcast to shipping concerning aircraft in distress will be sent in one of the following forms:-

(a) Concerning a known aircraft casualty:-

"Rescue aircraft begins S.O.S. . . . (followed by the text, giving a position in latitude and longitude and including a request to any ship near the position to answer the message and give its identity, position, and proposed action.)