Why NZ 6207, the first of the six Skyhawks that the RNZAF lost, crashed at Bulls on 18 Oct 1974

Skyhawk NZ 6207 had been planned to take part in a deployment to Singapore the following week.

One of the pilots who had been flying the aircraft reported “low oil pressure” on the previous flight.

The oil pump was replaced by the maintenance personnel, and ground run satisfactorily. There had also been a repair on the left-hand aileron that required a test flight.

As the majority of the personnel were going to a big parade in Palmerston North to celebrate “Freedom Of The City” [ability to march through the streets of the city with drawn bayonets on rifles], Wing Commander Fred Kinvig, who was the Officer Commanding Flying, was asked to do the test flight.

They were actually getting into the busses and trucks to take them into Palmerston North when W/Cdr F Kinvig ejected,and had to wait until they got back, 3 to 4 hours later, to find out what had happened.

He took off normally, did two circuits normally and on his third circuit, as he was overhead Bulls he called an emergency.

His last transmission to ATC [Air Traffic Control] in the Ohakea control tower was

“ Mayday, Mayday, Mayday, I have a slight problem, I’m not goingtomakeit I’mgoingtoeject”
Whoop, whoop, whoop as the Sarbe [ location finding beacon] was activated by the seat ejecting.

[it makes interesting listening, the first words are in his laconic style, the middle is quicker, the last bit there is no pause, it is just one word]

The W/Cdr ejected over the top of the local school, where most of the children’s parents were in the RNZAF.

He landed on top of the school boundary fence and the survival pack that he hadn’t had time to release properly swung forward and broke his leg.

The remains of the aircraft were very visible through the fence in a paddock a quarter to half a mile away.

The only fatality was the best pedigree and most expensive bull in New Zealand.

All of the fire engines left Ohakea at full speed, they thought the aircraft was in the school grounds, so they followed one another in through the school gates.

The leader, a Land Rover, realized that the aircraft was further down the road, so he headed out of the school gate again, unfortunately, the second to last fire tender was still coming through the single lane gate at the same time.

They meet head-on.

The only fire engine that arrived on the scene was the “household tender” complete with ladders, but no water.

Fortunately, there was no fire, the ambulance took the W/Cdr to Palmerston North hospital for treatment.

At the subsequent court of inquiry it was found that two years prior to the crash, the oil pump had been stripped, serviced, and reassembled at the RNZAF repair depot.

It was found the center portion of the oil pump had been assembled inverted, which prevented the lower pressure pump from sealing and providing oil pressure. this also increased the length marginally.

One of the sections of the engine this oil pump fed was No 6 bearing, placed just behind the second turbine, in the rear of the engine.

The jet exhaust going past this area is in the 700 to 750 degrees centigrade range, the heat that gets to the bearing will ruin the oil it comes in contact with, for this reason, the bearing was a “total loss bearing” with enough oil for approx. 40 minutes running/flying without replenishment.

Allowing twenty minutes ground running, two and a half circuits about 20 minutes, the rear bearing seized, the engine ceased rotation, and, without the engine the Skyhawk flys like a brick.

When approached Pratt and Whitney said that this could not happen, it took a Kiwi to do the impossible again.

Interestingly the serviceman who did the servicing on the oil pump had died in the intervening two years, which left the court of inquiry nobody to punish.

Because of this incident, the repair depot made a “Go / No Go” gauge to check the assembled pumps length and ensure it never happened again.

Photos Official