NO

10

Details of Sighting

Date 9th April 1979 Time 3:30AM Place 40º45'S 179º15'W

Date 9th April 1979 Time 3:30AM Place 40º45'S 179º15'W

Date 9th April 1979 Time 3:30AM Place 40º45'S 179º15'W

The target was most distinct at -1.30 of tilt… and had the appearance of a light-medium cloud

Report

TELEPHONE: WEI 3000 Ext 886

No 5 Squadron
RNZAF Base Auckland
Private Bag 2
AUCKLAND

12th April 1979

The Chief of Air Staff
Royal New Zealand Air Force

Attention: Public Relations Officer

For Information:

Operations Group

UFO'S?

1.At 0330 on 9th April 1979 we were on the north bound leg of a patrol at 9,000 feet when a radar contact was obtained in position 3710S 17130W. This contact, bearing 116/20nm from the aircraft appeared to be keeping formation with the aircraft.

2.We turned on to investigate, and, whilst homing on, the target was sectored upon and the tilt control varied. The target was most distinct at -1.3º of tilt, indicating a target below us, and had the appearance of a light-medium cloud, 3nm long, along track (116º) about 1nm wide. Throughout the homing to ‘On Top’ there was no target movement. After the ‘On Top’ the contact was lost (i.e. aircraft to the east of target) but was regained when the aircraft was again to the west of the target. Despite two homings to ‘On Top’ nothing that could explain the target was seen either above or below us.

3.As the AEO and Radar Operator I believe this contact to have been a cloud contact at a true distance of 404nm on a bearing of 116º true from its apparent position.

4.The P3B radar has a PRF of 400 PPS giving a PRT of 2500 micro-seconds, this limits the max. theoretical range of the radar, (due to time available to ‘listen’ for an echo) to 202nm. Normally at that range the power output would be insufficient to allow detection of anything but the most perfect reflector. However, with atmospheric ducting this range could be increased significantly, allowing the echo to come back not in the listening time for its own pulse, but in time for the next, or even one after that. This would mean that targets would be displayed at a range of X-202 or 404 or 606 etc where X = the actual range of the target from the radar.

5.If this phenomena were to happen in an aircraft travelling at say 300kts and the real target were say 424nm away, then the target would appear to be at a distance of only 20nm. Furthermore the target would appear to keep formation with the aircraft because the true relative bearing would only alter very slowly. The radar would only be able to pick up the contact outside of 404nm because as the range closed to say 403nm the echo would arrive back in time, not for zero range on the third pulse, but in time to appear as 202nm on the second pulse’s ‘listening time’. Although the contact was not observed coming in at extreme range after the ‘On Top’ due to display limitations, I believe the above to be an explanation of the contact we gained.

6.After extensive enquiries about cloud formations around New Zealand at that time, the Wellington Met Office informed me that the only significant cloud at that time was a belt of high top cloud running north east/south west through 40S 180E/ W which coincides with the position of our contact in position 4045S 17915W. This position is calculated by taking 404nm from the last seen position of the apparent target on the final bearing of 120ºT.

7.Had this contact been picked up by a less flexible and well equipped platform the result would almost certainly have been another UFO sighting report. Perhaps this incident, as a provable example of radar ducting is of public relations value.

(B.J. GODWIN)
Flying Officer
for Officer Commanding

Enclosures:

1.Chart
2.Weather Reports

Map showing location of cloud

Report taken from file number
AIR 39/3/3 Volume 3

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