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OPERATION ICEBERG Page. 1.
(Appendix No. V to V.A.B.P.F. No.1092/4 of 9th May, 1945)
AIRCRAFT DIRECTION AND RADAR REPORT
INTERCEPTIONS
1. Fleet Fighters have operated continuously during daylight hours when in an operational area. Fighters have been employed both in defence of the Fleet and directed offensively against hostile aircraft on passage to and from the OKINAWA area.
2. It is considered that 10 attacks were launched against the Force. Of these 7 were intercepted and driven off before they closed the Force. In 3 cases individual suicide aircraft broke through the fighter defences and attacked.
3. A total of 43 ship-controlled interceptions were successfully made resulting in 24 kills and a number of "possibles". In addition numerous interceptions were made of American search aircraft which could not bo identified by other means.
4. In some 7 cases interception failed owing to errors in height-finding and the violent evasive action and greater speed of the enemy DINAHS which made good use of cloud cover. Under these such conditions the fighters cannot be relied upon to destroy search aircraft in every case.
ENEMY TACTICS
5. Attacks have been made by small groups of 4 - 6 "suicide" bombers which are usually single-engined aircraft escorted by one twin-engined "Pilot".
6. Suicide aircraft do not rely upon mutual support. On interception or on sighting the force, the group breaks formation and each aircraft seeks to approach and attack individually
7. Intruder tactics have been used by aircraft which follow in behind returning strikes.
8. To ensure immunity each aircraft has to be shot down.
9. Suicide attacks may be made at any height according to weather conditions. Attacks low on the water offer the greatest difficulty owing to the short range at which they are detected.
RADAR
10. Types 281 and 79B have performed satisfactorily within their known limitations. Japanose dispersal tactics aggravate the difficulty in distinguishing between different aircraft at approximately the same range.
11. Type 277 has lived up to expectation as a low cover set providing reliable low cover to 25 - 30 miles with occasional ranges of 35 - 45 miles on aircroft between 1000 to 3000 feet. Height finding has been disappointing owing to the difficulty in picking up the right aircraft without an azicator.
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OPERATION ICEBERG Page 2.
(Appendix No. V to V.A.B.P.F. No.1092/4 of 9th May, 1945)
12. No small part of the successes have been due to the greater ranges and accurate height-finding of the SM in INDOMITABLE. This set has been invaluable.
13. The lack of bearing discrimination in Naval Interrogators is a serious limitation when large numbers of aircraft are operating.
14. Radar Type 793. During the oporation considerable interference was experienced on Type 793 sets in the Task Force. The interference was in a general Westerly direction and radically reduced the operational value of the set, especially from noon until late evening.
By Test Scan investigation it was revealed that the interference was at a distance of between 1,200 to 2500 miles, occurring on Type 79 as a second scan effect.
H.M.S. INDOMITABLE has reported a successful remedy by reducing the repetition rate to 25 cycles, achieved by a. MOD "flip-flop" circuit.
It is intended to incorporate this modification in all Type 793 sets of the Task Force. A detailed report will be submitted in due course
DEFENSIVE TACTICS.
15. Experience has shown the need to intercept at maximum ranges in order that combats may be completed and all hostiles that have slipped through may be identified and tracked well outside the Force Gunnery zone.
16. Low attacks which are only detected at 20 - 25 miles will probably not be intercepted outside 12 miles. Combat will probably not be completed outside the gunnery zone. With Jopanese dispersal tactics and large numbers of defensive fighters, interception at close range results in radar saturation and the breakdown of tracking and radar target indication. The presence of friendly fighters further confuses visual gunnery control.
17. The constant employment of a total of up to and over 20 fighters, has allowed 4 or 8 of those being sent out to intercept at extreme range. Interceptions outside 30 miles have become the rule rather than the exception whenever the range of detection has allowed. Interceptions have been made at up to 105 miles but this was on a Liberator.
18. In an effort to increase the range at which low attacks are intercepted, low patrols included in the above are flown on fixed lines 10 miles from the Force centre. It appears unlikely, however, that any solution will be effective without the use of properly fitted Radar Picket ships stationed up to 30 miles outside the A/S screen.
19. In order to identify "intruders" and assist in the identification of returning strike aircraft, a Radar Picket cruiser accompanied by a destroyer have been stationed 30 miles from the Force on the bearing of the target. Rotating fighters are required to submit to scrutiny by a fighter patrol controlled by the Picket ship before closing the main force. This expedient has been of great value.
AIR PLOTTING
20. The standard of air plotting has steadily improved and a clear picture is now available except when there is much activity at close ranges. Rigid control by the controlling ship, and a full appreciation by each ship of its part in the production of the picture as a whole, are first essentials if unnecessary alarms aro to be avoided.
21. With numerous patrols flying at all ranges up to 30 miles, it has been found necessary to detail a special radar guardship with the primary responsibility of identifying and tracking all patrols.
22. With reference to para.18 of Enclosure V of A.C1's No. 0109/12/564 of 26th April it is, considered that cruisers which have recently undergone refit should be quite capabile of carrying out picket duties, given surffcient practice and at least two fighter direction officers.