Lan Vinh Do
Well Known Member
HI
Since a year I experiment rare event of 1 or 2 second only.
i normally have vibration for 1 to 2 second and it stop. When it happened in calm air, i had the feeling that i hit something with the wheel pant ( just the sound)
At begining, i tought i was crossing the turbulence of another aircraft as it often happen near a airport.
The majority of the time, it's after levelling or in a descent after a long flight. It happened once juste after take off ( 20 ft in the air ) but it was just after a run-up after without the cowling ( after the annual) put back the cowling and doing a test flight.
it was happening before this inspection. All spark plug has been change, mag was sent for the inspection and reinstall, fuel filter all clean, gascolator filter clean.
i have a io 540 new from aerosport with a silver hawk ex, one mag, one plasma III.
no water on the preflight check. Plane always inside when not flying.
today it happened just une minute after levelling, flew over the airport and mag check and llama III check ok.
I download the engine data and after zooming it, i can see the get of cylinder no 2 went down from 1164 to 1143 in one second and stayed there for 4 second before to go up again exactly at the moment of the vibration. I was was just touching the mixture to lean but i don't think i had the time to really lean.
Mag check and plasma III check
It happened another time in a descent fuel pump on in final. again only 1 second. always cylinder no 2 ( orange)
all other engine parameter normal. Fuel pressure, FF, oil temp, CHT. it's so short that it's hard to pick.
any idea?.
i don't think it's the ignition as the get go down and it mean that my mag and plans III would need to fail at the same time. ( because the get go down and not up) Am i right?
thank you
Lan Vinh Do
Since a year I experiment rare event of 1 or 2 second only.
i normally have vibration for 1 to 2 second and it stop. When it happened in calm air, i had the feeling that i hit something with the wheel pant ( just the sound)
At begining, i tought i was crossing the turbulence of another aircraft as it often happen near a airport.
The majority of the time, it's after levelling or in a descent after a long flight. It happened once juste after take off ( 20 ft in the air ) but it was just after a run-up after without the cowling ( after the annual) put back the cowling and doing a test flight.
it was happening before this inspection. All spark plug has been change, mag was sent for the inspection and reinstall, fuel filter all clean, gascolator filter clean.
i have a io 540 new from aerosport with a silver hawk ex, one mag, one plasma III.
no water on the preflight check. Plane always inside when not flying.
today it happened just une minute after levelling, flew over the airport and mag check and llama III check ok.
I download the engine data and after zooming it, i can see the get of cylinder no 2 went down from 1164 to 1143 in one second and stayed there for 4 second before to go up again exactly at the moment of the vibration. I was was just touching the mixture to lean but i don't think i had the time to really lean.
Mag check and plasma III check
It happened another time in a descent fuel pump on in final. again only 1 second. always cylinder no 2 ( orange)
all other engine parameter normal. Fuel pressure, FF, oil temp, CHT. it's so short that it's hard to pick.
any idea?.
i don't think it's the ignition as the get go down and it mean that my mag and plans III would need to fail at the same time. ( because the get go down and not up) Am i right?
thank you
Lan Vinh Do
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