I'm not sure id be bothering to change the design of the trim system in a 7 based on that report. What have you changed?

Gets airborne, trims forward and accelerates just above the ground, pulls up (while re trimming) and stalls.
My interpretation is deliberate pilot action for reasons unknown. I see no trim failure mode that could replicate that. Others may have different theories.

Very sad. :(

No trim run away????

I have put in a system that prevents trim run away, saw it here on VAF, cant remember what it is called, but was cheap and seemed like a good idea to me.

Called TCW saftey trim

Condolences for friends and family.

Am I reading this report correctly? Oil is mentioned several times, and the data stream showed some oil pressure jags near the end of data. Oil on R/S wing and HS, oil in cockpit, oil on inside of canopy. Is there any further information yet? Choking oil fog, fumes in cockpit - canopy opened resulting in evacuation of paperwork etc - - - is that the implication from the facts given?

I can not see if the pilot was wearing a chute. Maybe I missed it.

My guess is that the low volume of accidents in Canada/Australia in comparison to the US.

Runaway trim is a serious problem in large aircraft. Not so in our RVs. You can safely fly an RV with the trim in any position.

-Andy

Thank You
 

Thank you Richard and David for the report. I've been looking for answers to this accident ever since it happened and appreciate the info. My condolences to all involved.

If it hasn't been done already, I'll post a note about this report of this very sad accident into the RV-12 blog.

I can?t speak to Australia, but I know that in Canada the TSB does not do much of an investigation for most private general aviation accidents. There isn?t much new to learn from most accidents, so a full investigation isn?t a good use of their limited resources. But, if they see an accident that looks like there might be something new to learn, they do a proper investigation.

Trim movement
 

I think without further investigation that the trim readings can't really tell anything.
The report says the trim units are read by the dynon as a figure of +1 to -1 the trim is shown to go from -.015 to as low as .027 then up to .005
Without knowing if the travel readings at the full deflection were +1 to -1 these readings may have been as little as 1% of the travel. The trim may have just been experiencing normal air loads not actually been moved? You need to know the full scale of movement.
Maybe someone with an dynon sky view on an -12 might be able to answer.

Peter

Fair enough Phil,
I've had a few trim incidents over 500hrs in my 7. Mainly maps resting on the trim switch and the like. I also blew a fuse once and had the trim stuck in full nose up for a short local flight. Got my attention but certainly no big deal. I agree with Andy. Trim motor malfunctions in our aircraft shouldn't be a disaster.

The main issue with the -7 trim in my experience is that it's too sensitive at cruise speeds. So speed scheduling is a nice to have. I think TCW does that as well perhaps?
As it happens, I just replaced my original autopilot with the Garmin. The beauty of the Garmin GSAs is that they drive the trim servos. So now I have auto trim, speed scheduling and runaway trim protection (in both axes).

I don't think people should be fretting over any airframe malfunctions in the RV12 incident. Multiple witnesses, the flight data and I believe cockpit and external videos all point to the same conclusion.

Sounds like there is a fair bit of work being done on the Chelsea accident. No doubt because of its high profile location. Hopefully we get some answers in the near future.

Cheers

To add to this, as i've assisted the local TSB office on two accident investigations involving amateur-builts: In Canada the TSB works to obtain the best "bang for the buck" from their time and services. They will happily investigate amateur-built accidents, *if* there isn't a "higher value" task at hand.

Generally there are enough commercial incidents involving an aircraft type that's widely in use (Cessnas, Beavers, etc.) or accidents likely to involve large numbers of the paying public (Airliners) to keep them busy... Any smoking guns they find there are more likely to maximize the numbers of lives saved if they focus on those high value targets. One- or two-off amateur-built designs, in contrast, get little attention unless others from the aviation community offer to assist (that's how I got involved).

The TSB has done excellent investigations on at least one RV accident that i'm aware of (an -7A inflight breakup) when staff were available. I suspect the fact that RV's are becoming a significant part of the amateur-built fleet in Canada may also contribute to their interest in investigating... Despite the wide variety of builder modifications applied during initial construction, in general the basic structure matches the plans on the majority of RV's.

For those in the US who feel they aren't seeing much investigation happening, it might be an option to offer to help. There is a lot of builder expertise in the RV community, and the knowledge base may not exist in the local NTSB office. You may find (as we did) that the local office was very keen to learn, and welcomed the assistance.

I'll caution though, that accident investigation isn't for everyone... Especially when it comes to investigating a fatal accident.