Dear Forum,
Has anyone out there experienced the "turbo surge on startup" that Rotax
say can occur, and for which they specify a kill switch within reach?
The reason for the question is as follows:-
On 14 Nov 04 I aborted a takeoff , as the engine did something I have never
before experienced, in 100 hrs. At only half throttle, on T/O run, I
suddenly felt full power, and was airborne very quickly. Airmaster prop was
on fine, and I did not note MP. A few seconds later the power dropped back
again, I suspect to the throttle setting. At no time did the engine misfire,
and all checks had been normal. I elected to land straight ahead, and it all
would have been a non-event, except for the cane-drain that I had forgotten
about. These drains criss-cross the sugarcane fields here, about 2-3 m wide,
1-2 m deep. One of these crossed the runoff area at the end of the runway. I
over-ran the runway, wet grass, so braking and groundloop not very
effective, hitting the drain at I guess 15-20 Kts. The nose of the A/C
impacted the far bank, then slid upwards about 60-70 cm, ie low speed, but
significant decelleration.
My injuries included a compression fracture of the first lumbar vertebra,
unstable, and one fragment was displaced rearward 5 mm, compressing the
thecal sac. Some very clever surgery involved removal of the body of the L1
vertebra, along with the discs above and below, and replacing them with a
titanium cage, which contained the bone graft, which will hopefully fuse
three vertebrae into one.It was pure good fortune that the injury did not
result in paraplegia, and hopefully I can expect full recovery. I was
wearing the standard 4 point harness, and suffered no other significant
injuries . I am aware this was the subject of discussion earlier - whether
the harness as designed promotes compression fractures. That is another
topic.
Back from hospital 2 days, so have not inspected the A/C yet, but can say
the prop has one blade broken off near the hub, the windscreen is split, so
I suspect some damage in the firewall area.
In musing over what happened, I suspect that I experienced turbo surge, and
that the "faltering" was simply the end of the surge. If that were the case,
I would probably have been OK to kill the turbo, and continue the T/O
without it. There would have been plenty of power.
Has anyone experienced anything similar? ( the engine behavior, I mean. I do
not wish the back experience on anyone!)
Graham Higgins, in Oz
|