An error of omission
An error of omission
And now, the rest of the story:
On June 20th, my friend and I decided to take a short cross-country flight to a nearby airport for a "$100 hamburger" at a nearby restaurant. We checked the weather, fueled up the machines, conducted our preflight inspections. It was about 12:30pm and the skies where clear and generally a nice day to fly. I have a small engine go-ped type pre-rotator on my gyro and I moved my gyro to a clear spot to start and warmed up the goped engine so it would easier to start back up when I reach the runway. I usually have to leave a small amount of manual choke on the pre-rotator, and that day was no exception.
I taxied down to the end of runway 12 (the wind was from 140 varying to 180 at 5-7mph) and made a radio announcement that we would be a flight of 2 gyros departing One Two and heading to the north. I proceeded to the runway and lined up on the center when I noticed my Microtim electronic altimeter had powered off into the power saving sleep mode. I have a 4 point seltbelt and I must remove it to reach the altimeter to reactivate it. (This was to be the primary distraction). I refastened the seatbelt and did the F-I-T pre-takeoff checklist (Fuel, Instruments,Traffic).
I changed my pre rotator brake last September from the Wunderlich style to a caliper/disc brake style because I was not able to engage the Wunderlich type very well because of the cyclic/ rotor head control rod geometry bottomed out on the stops before it could apply the rotor brake very well. I had a friction control for the new rotor brake that would allow me to keep the brake applied hands free. I had about 10 to 15 flights with the new pre rotator.
I started the pre-rotator and began the rotor spin up. I usually spin up to 180 rrpm before I release the pre-rotator and begin the take-off roll. That day I could only reach 150 rrpm which I incorrectly attributed to leaving on too much choke on the pre-rotator, decreasing it’s power output. I began the take-off roll with about 1/2 throttle as usual and felt the wind pressure on my body varying from the changing wind. I had traveled approximately 200 to 300 feet down the runway when I felt an unusual vibration that felt like a front wheel shimmy. (During the early days, when I practiced taxiing without the rotor, my front wheel developed a severe shimmy that left a strong impression on me! I have since changed the front wheel assembly and included a dampening device.) I looked down at the front wheel to see if my wheel developed a new shimmy. All the while, the rotor was not accelerating normally. Then, I felt the rotor hit its stops at the rotor head four times in less than 1 second and the gyro rolled.
The next thing I knew, I was lying on my side strapped in the seat and heard an engine running. I immediately pressed the main engine kill switches but still heard an engine. I realized that the goped pre rotator was still running and shut that down too. I then released the seat belt and walked away.
I didn’t receive any cuts or bruises. My hands never touched the ground during the roll. Even the helmet didn’t have a scratch. My lower back was a little sore but nothing else. I knew I was very lucky but the site of my gyro was very depressing. That machine deserved better from it’s pilot.
OBSERVATIONS AND RECOMMENDATION:
I did not update my take-off checklist to include RELEASE ROTOR BRAKE.
I did not stop my takeoff roll immediately to investigate why I couldn’t pre rotate to my normal 180rrpm.
I did not reduce the throttle and level the rotor at the FIRST SIGN OF VIBRATION. ( I was trying to diagnose the problem by looking at the front wheel for shimmy).
The wind may have played a role in this event, if the wind was crossed the takeoff acceleration may have happened more quickly and if the wind changed to a headwind, it would have added more air passing through the slowing rotor.
I have over 600 takeoffs and landing in gyroplanes and maybe complacency had settled in.
I would suggest everyone re-read the following post:
http://www.rotaryforum.com/forum/showthread.php?t=43417&highlight=russian&page=3
paying particular attention to posts 45,50,52,71,72,73.
I know I’m very lucky. My fellow pilots keep reminding me of this and thats a good thing. I’m slowly learning to forgive myself for damaging that wonderful machine.
Live and learn…….and rebuild.
Mike