The Glorious 74th Entry RAF Halton Aircraft Apprentices (The Coronation Entry).

Stan Norris Remembers.

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3. Hard to Believe but...

The Canberra T4 Servicing That went with a Bang!

When this sequence of events happened it was nearly 40 years ago and I was personally involved in only the first incident. Oh yes, there was more than one incident and they all featured one particular aircraft. I will not name individuals, the squadron or the station. The aircraft concerned was a Canberra T4. We had two on strength, tail numbers 849 and 861 but, if my memory is correct it is to 861 that this saga relates.

The swing or evening shift came on duty about 4.30 pm. The priority aircraft for recovery was 861 partially through a routine servicing but awaiting armament and electrical checks before further progress could be made. A Corporal electrician on the swing shift entered the aircraft and a few minutes later there was a significant bang! Without taking you through the actual servicing procedure and the whys and wherefores, when the Corporal applied power the canopy detonator bolts fired - curiously, only 24 of the 32 detonators fired. With the uneven stress created on the canopy the perspex cracked in all directions.

The Squadron Commander pressed for Disciplinary Action

Inevitably a unit inquiry was convened., conclusions and recommendations submitted. The Squadron Commander pressed for disciplinary action, the Snco i/c shift and the Corporal were duly charged with wilful negligence and negligence respectively and a Board of Inquiry was quickly convened. Legal Services were not satisfied with the submitted documentation and suggested that the unit re-convene the Board of Inquiry. This was done, but again the evidence was deemed unsatisfactory and unsafe to proceed with Courts Martial and the case should be dealt with at Unit level. The evidence was said to be very unsafe and the disciplinary action fizzled out with an admonishment to the two NCOs by the Station Commander.

Not Again?

Sometime later after I had left the unit, the aircraft was repaired and delivered to the line ready for use. Overnight there was a very heavy rainfall. Next morning, when electrical power was applied, the canopy detonator bolts fired, all 32 this time. The unit inquiry apparently concluded that the cause was ingress of water into the electrical system. For a second time 861 underwent the repair process.

And Again?

Repaired and ready for a squadron deployment to a neighbouring airfield, 861 taxied out piloted fittingly enough by the Squadron Commander himself - and the canopy detonator bolts blew! The findings of the unit inquiry? The seam on the thumb of the pilots flying glove was extra prominent, by about 1/16" to 3/32" and accidentally activated the canopy jettison firing mechanism.
I was told that this event featured in Air Clues although cannot remember reading about it.

Canberra 861: Question Time.

I never heard what happened to 861 after that. The rectification involved reaming out the bolt holes and fitting oversize bolts, but I think that could only be done three times.

Where did 861 go after the third uncommanded jettison? Scrapped? Ground instruction?
Did it happen again?
Why didn't all the detonators fire in the first incident? I never heard if that was investigated.

One Aircraft, Three Similar Incidents, Three Different Causes?

I was off the squadron when the second and third incidents occurred so my knowledge of them is third hand. It is a curious memory to retain but - one aircraft, three incidents, three different causes all in the space of a few months. Remarkable coincidences? An intermittent undetected defect triggering the circuit under three different circumstances?

In the years since I left the service, for some reason or other I have thought about those few months, very sceptically I might add, often doubting my own recollections. Or was it strange but true?


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