114 THE AVIATION HISTORIAN Issue No 22
than a couple of feet. We could see for miles
and the area around Kinloss and Findhorn Bay
looked absolutely magnificent.
Problems begin
We had just started the air test checklist when
the problems started. Dave Rimmer, the flight
engineer, had the checklist on his lap and was
checking the engines’ anti-icing system. He
started with No 1 engine and watched the
temperature rise, before switching it off. He then
did the same with Nos 2 and 3, but it would be
No 4 that would be the cause of our problems.
The air-start valve light illuminated on the centre
console. This in itself was nothing to worry
about as, to my knowledge, it had happened a
dozen times before on Nimrods and had always
been a false alarm. It was more of a nuisance
than an emergency. On this occasion, however, it
was not a false alarm.
Above No 4 engine was a loom of wires; over
the years, with the vibrations, the insulation that
covered the wires had worn. Unbeknown to us,
two wires were now touching; one of those wires
went down to the engine anti-icing system, with
the other going to the starter motor. We later
learned that more than 20 years previously, an
RAF engineer had been looking at the nut that
held the turbine assembly in its titanium shroud
within XW666’s Rolls-Royce Spey engine, and
had expressed concern that this particular nut
was not strong enough; if too much stress was
applied to it then there was a chance it would
shatter. The turbine assembly would then be free
to rotate itself off its mounting and come into
contact with the engine. If that was to occur it
would cause a catastrophic explosion.
The short circuit had supplied power to No
4 engine’s starter motor. The turbine within
the starter, under no load, with the engine
already running, wound up to more than
100,000 r.p.m. in a few seconds, and in doing
so imposed stresses on that £5 nut whose job
was to hold the starter turbine in place. Just
as that clever engineer had forecast, the nut
failed and allowed the spinning turbine to clear
the starter motor casing before coming into
contact with the engine. Needless to say the
catastrophic explosion did occur, which blew the
lower casings off the engine and penetrated the
adjacent fuel tank. Fortunately the tank was still
full. Two hours later it would have been empty
except for vapour and the outcome would have
been dramatically different.
Back on the flightdeck we didn’t know that all
this was going on only feet from where we sat.
The first indication we had that something was
really wrong was when the fire-warning, both
aural and visual, for No 4 activated. The copilot
and engineer began actioning their checks and
I began to turn the aircraft and commenced a
descent back towards land and Kinloss.
The fire spread rapidly through the engine
and was quickly followed by a fire-warning —
false as it turned out — for No 3. All four fire
extinguishers were quickly used, to no avail
— the contents going overboard, although we
didn’t know it — and one of the three safety
team down the back, Steve Hart, began reporting
on the state of the fire. Grey smoke first, quickly
turning to black, then the first flames and
numerous reports of panels breaking away and
the wing appearing to be melting. Steve then
reported that flames were coming out of the
thrust-reversers. With thousands of pounds of
fuel being driven out at 350 m.p.h. (560km/h),
we resembled a blowtorch.
Steve’s accuracy of reporting was nothing
short of inspired. I saw the fire through his eyes
and made the most dramatic and important