AD 2000-25-02R1

[s2d]

Just have a question that may have been addressed on the spar AD.
If i have a C-90 installed in my airplane, do I have to do a repetitive inspection on the spars because the engine is rated at 95 hp for 5 minutes ?

thanks
Brian

[MikeB]

My understanding is "no" as it's technically rated at 90 horse.

[s2d]

Thanks mike. Sure would like to see something in writing by FAA. Might have to call the number on the AD

[Paul Agaliotis]

The FAA has it's information based on max continuous power per FAR 21.128 and 33.7. In Part 21 they refer to a test at max T/O power for certification. Since Group 1 aircraft include the 7EC and FC ( both with C-90's) it's safe to say that the C-90 is acceptable for installation on any Aeronca. With out removing it from Group 1 status.
About calling the FAA, I would not bother them. It's kinda like calling the IRS and asking about the tax rate on all of the gold bars you found while digging that new septic tank. You might not like the response.
Paul

[MikeB]

Paul puts it much better than I but I've never really understood the AD as the spar is supposed to be carefully inspected on each annual anyway and the potential failure points are pretty well known. This becomes more important when a wing drag or ground loop is involved and I wonder if it doesn't get down to referring to the AD on over 90 HP when the annual inspection is written in the log book. I noticed my IA usually does on my 100 HP L16 and used to do it on my 65 HP Champ, too.
Mike

[Paul Agaliotis]

Mike hits the nail on the head. No matter how slight the damage may look it's very important to take a peek at the strut attach plates on the OB end. That's the point where they will break.

The spar is the same diamension from the 7AC up to the 7KCAB, the G/W was increased from 1220 to 1650 all with no spar size increase. And some are in the Utility and Aerobatic catagory. This is where the Group 1 and Group 2 aircraft are separated. Group 1 are the 1200/1400lb aircraft and Group 2 is everything above.

The FAA jumped to the conclusion that, if you wanted a higher horsepower engine you also wanted the higher G/W. This is not always true, but once the AD is written it is almost never canceled and more often revised to make it even more confussing.

You're dealing with career bureaucrats trying not to make waves and get their pension. So when they add 2+2 they come up with a rutabaga.
Paul

[brink]

The AD from what I see is a cover your ass AD, I’ve seen a lot of that lately, I’ve inspected several Champs and the owners are rightly concerned, I’ve got one set of Spars that were removed for cracks and replaced with newer units,now mind you this was an expensive, both wings and 4 spars I looked at them, this IA changed jobs and moved, I looked at the recover and approved the Stits precover, did a little drag wire adjusting, with my long level, really a nice job, rebuilding the wings on this Champ. The former IA advised that the old spars needed to be cut up, he didn’t do that, I paid him for his used spars, they were perfect just a few scratches pulling of the ribs, why were these spars replaced? The tips on both wings had what I called pinch pockets on the forward main spars, no history of ground looping or accidents kind of a forward worping on both spars. But very slight but you could see it with the eye. What I did I took 2 6/6 6 foot planks and 8 C clamps, in this process I had to tighten the C Clamps several times, but those spars are perfect now, a good thing to have a set of spars, I’ve been told don’t store spars flat always store them vertical, base to tip straight with a level. I know their original units from Middletown,

[rkittine]

First, I was under the impression that the AD covered 100 HP and up engine configurations, but maybe it is OVER 90. It has been a long time since I looked at the AD.

In any case, on my Wooden Spared 7CCM I did not want to either cut inspection holes in the top of the wing, but also did not want to rely on old spars. Fortunately a friend was able to get a Practascope from a local hospital when they upgraded in newer equipment. We used it at each annual to get into the wing and check the spars.

I sold that plane and three weeks later the new owner had a mishap and clipped a tree with his wing on landing avoiding a truck that had pulled on the runway.

When they ripped down the wings, they found major cracks in one set of spars. Interesting thing though was that they were not on the wing that hit the tree and according to the mechanic that took the wings apart, he swore that by their appearance, they were VERY old cracks and we were all lucking nothing happened to those spars in flight.

Regardless of the regulations, we have to realize that flying 70+ year old aircraft, especially those that have not ever or recently been rebuilt, requires more diligence. Just like the Airframe Corrosion issues under the aluminum lower door frame trim that so often happened.

Best Flying - Bob

[brink]

Ya you read The AD right, if that guy hit a tree with one wing the impact could have easily cracked the non impact wing spars I would not be surprized if the wing mounts at the fuselage were even torqued a little. The point was proven in all the accidents serious negative G’s were applied, and Bellanca should have applied Aluminum Spars, I see many Aircraft out their, aerobatic experimental with all wood wings, and other aircraft 20 years older than our 7AC with Spruce even Fur spars that hold up very well as long as a little sense is applied in their maintenance and operational use, not to offend just my point of view.