Bell 429 - undemanded yaw question
 

Are there any 429 operators out there who have had instances of undemanded yaw, either on the ground or in the air?
One happened recently in UK and it would be educational to know if has happened elsewhere - thanks.

It would appear there is some history although it’s not clear what nature the symptoms of this last incident were:

https://www.flightglobal.com/news/ar...rators-420608/
Bell 429 TR Pitch Change Link Bearing Failure - Aerossurance

Thanks - but as I understand it the aircraft yawed left in the middle of a PAC.

was the sab systems switched off or on?

Also...what was the Yaw Pedal position immediately prior to this sudden yawing?

What kind of surface was the aircraft on at the time?

I can think of several relevant questions particularly if there are no mechanical defects found that would explain the event.

Sas - to my knowledge there were no extenuating circumstances - a post maintenance ground run with a very experienced pilot both on type and in role. Apparently, the downloaded data showed a yaw input of less than 1 sec so TR servo would be suspect - I assume the AP would be engaged for a PAC.

Crab: Speaking to my colleagues in America yes, the AP should be disengaged for PAC.

Crab:
we had a servo problem,not with the tailrotor, but the cyclic. It was discover during the daily check.

KK:
Nothing prevent the crew to do a power check without the AP, I guess it depend of the company SOP.
FH

Yup - been there done that. Auto pilots coupled up and all of a sudden it yaws about 45 degrees left and then straightened itself up. We left it coupled and then it happened again, so we uncoupled and flew home. If I remember correctly the factory set pedal friction was too tight and the autopilot over compensated for it.

vaqueroaero:
did your event occur in flight or in hover?
Cheers
FH

In flight. I believe all we had was the three axis autopilot at that point in time.

WAA grouded
 

I suspect that out of the 39 or so HEMS machines around the bazaars, it is likely that more than one of them will be waiting for some spares at any one time - when you say 'still on the ground' is this an ongoing issue?

Cheers

TeeS

Not sure if it's related, but an emergency A/D has just been released by Transport Canada regarding loose tail rotor gearbox's on 429's

http://publicapps.caa.co.uk/docs/33/CF201818E.pdf

TeeS, your right when you say that at any one time there are a number of aircraft waiting for spares. I thought as a air ambulance they would declare the aircraft AOG in order to have priority over others, unless this did not happen in order to save money!

Wiltshire Air Ambulance Bell still offline
 

Wiltshire air ambulance is still offline, is this true?

Yes. Wiltshire's 429 has been offline for a month now, apparently a Bell Test Pilot has visited.

To Bell's credit they are clearly taking this incident very seriously,

Surely there will be a press release from the WAA, it's been very quiet on that front!

Still waiting for this press release!!