Citabria 180 hp STC's thread drift new thread

i agree with everything you said Alex but the low hp Chief isn't subject to the AD.

the owners, at the time and as I've been told, were more interested in selling replacement wings than airplanes so they went along with the AD. I believe that was before ACA bought the rights to everything.

rrgarding wood structure aerobatic planes, pull one apart after 1000 hrs of acro and there will be stuff broken under the fabric. there are strategies to avoid it but repairs are inevitable.
 
I don't think
Bartman said:
the owners, at the time and as I've been told, were more interested in selling replacement wings than airplanes so they went along with the AD. I believe that was before ACA bought the rights to everything.
Click to expand...

ACA bought the rights to the 8 and 7 series in 1990, and put the Super Decathlon back into production that same year. The AD was not proposed until 1998. At the time, ACA had already published two service letters detailing the inspection procedure which the FAA eventually adopted as the AD.

I have spoken to the owners and managers of ACA about the issue. Melhaff senior has strong feelings about the wood spar, but I do not believe they are based on greed. From his perspective looking at the entire fleet, the metal spar is simply a more consistent and reliable engineering approach. Metal spars do not require special care and periodic refinishing, and they do not require special knowledge and experience with unusual, older technologies to inspect.

I can't say that I blame him for taking that position, since the liability ultimately lands on his family business. Early on, ACA was involved in several court cases involving liability for wood wing failures, at least one of which resulted in a fatality, and he had to testify. I have not spoken to him about it, but I heard from someone who did that he gets quite angry when pressed on the issue.

Overall, I think ACA has been reasonably supportive of wood spar owners. I would like it more if they were willing to service aircraft with wood spars, but I understand their decision to keep that separation.

IMO, if money were their only motivation, they would not sell the metal wing upgrades. Based on the price, I do not believe those are huge profit drivers. They probably have to sell 10 wing kits to equal the profit from one new aircraft. You could argue the smarter business decision would be to let the wood wing airplanes die and shrink the fleet, which would result in increased demand for their new aircraft. That they have not done so speaks to their loyalty for the type.
 
Not sure I understand that. Are you saying simply that they sell wood wing parts, and if they chose not to all the wood spar aircraft would somehow die? I had not heard of serious wood wing component failure, so I assume attrition would be a function of wing damage due to hitting things?
 
The AD was issued because of spar failure in flight of a Scout that had previously been wrecked in an “overturning” incident and the wings,( although both wings were damaged) were supposedly found not to have compression failures and put back into service. Subsequently failed in flight as a glider tow. Then they inspected two additional spars from other aircraft that had been damaged by overturning or ground loop wing contact with the ground and found fractures in the those spars. What a surprise. If you crash your wing into the ground it might be broken. FAA response was to require all wood spars be inspected forever whether damaged or not.
 
Ed,

What you said is consistent with what I had been told, that the metal spar wings were already in development before ACA bought the rights. The rest of what you wrote is interesting in that it fills in the story, I thought the AD came sooner than '98.
 
That was my understanding as well - off-airport landings, hitting things - those are where the compression cracks come from. A better and safer way would be a tear-down inspection after each impact - scuff a wingtip on a ground loop? Pull the fabric off the suspect area and study it. The AD is a joke. Takes a very long time, and you still cannot see anything.

I always back up that silly Bend-A-Lite with a modern TV probe. And still . . .
 
Most people agree the cause is impacts. The problem is how to know for certain the impact history of an aircraft. In theory, all damage should be logged. In reality, if you have a "minor" mishap such as dragging a wingtip, there are powerful ownership incentives not to record it in the logs. How many taildragger aircraft have ground looped, had the cosmetic damage repaired, and been placed back into service without documenting the incident?

My Decathlon is 44 years old. The original owner and IA are long dead. How do I know whether anything has ever happened to my wood spar?
 
Your first inspection should reveal damage. The problem, of course, is that damage is easy to miss, because the fracture lines are so small and difficult to spot.

If you miss them the first time, they would have to grow to show up next year - but compression fractures apparently don't "grow," they just "let go."

The good news is, this has never been a problem for Decathlons.
 
You must log in or register to reply here.
Back
Top