FAA Issues ADs For Pipers, Bonanzas

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The FAA published Airworthiness Directives this week that affect certain Piper Cherokees and turbo Bonanza airplanes. The proposed Piper AD (PDF) was prompted by reports of corrosion found in an area of the main wing spar that’s not easily accessible for inspection. The AD would require installing an inspection access panel in the lower wing skin near the left and the right main wing spars, if there’s not already one there, which would cost about $685. Also the left and the right main wing spars must be inspected for corrosion, at a cost of about $170, and all necessary corrective actions must be taken. These actions must be completed within 12 months or 100 hours flying time after the effective date of the AD, whichever comes first. The AD is expected to affect 11,476 airplanes registered in the U.S. The FAA is accepting comments on the proposed AD until Dec. 22.

The FAA also this week published a revision (PDF) of an earlier proposal, published in April, that affects turbo Bonanzas, adding more models to the list of airplanes affected, and adding a visual inspection of the exhaust tailpipe. The FAA has reopened the comment period, until Dec. 26, to allow the public a chance to comment on these changes. The proposed AD was prompted by a fatal accident in which the exhaust tailpipe fell off during takeoff, the FAA said. The NPRM proposed to add a life limit to the exhaust tailpipe v-band coupling (clamp) and, if the coupling is removed for any reason before the life limit is reached, require an inspection of the v-band coupling before reinstalling. The FAA estimates the AD will affect 731 airplanes and will cost about $500 to $800.

Comments (7)

Reading the proposed PA-28 Cherokee AD and Service Bulletin makes me wonder if this AD is really necessary. Only two (2) airplanes out of a fleet of 11,476 Cherokees have been found to have this corrosion problem, and thus prompting the AD. The FAA estimates a compliance cost of $855 to install the inspection plates and do the inspection, but if ANY corrosion is found it must be removed and further inspection accomplished. This will likely be much more expensive, and finding at least some light corrosion seems likely considering the age of these airplanes. It seems that this AD could easily exceed 10% of the value of a lot of these airplanes, and that's if nothing serious is found.

Considering the number of airplanes affected I think the question should be asked whether two airplanes out of 11,476 justifies the tremendous cost, and in fact risks permanent grounding and scrapping of some of these airplanes. The proposed AD doesn't give any details about the conditions the two problem airplanes encountered during their lifetimes, which makes me think of the old wing spar AD on Cherokees that was about to decimate the fleet before it was rescinded. As I recall, in that case the airplanes with spar failures flew bumpy pipeline patrol for years, and thus experienced out of the ordinary stresses. Perhaps if we knew more about the two problem airplanes we could argue for a similar consideration on the part of the FAA.

If you agree, I suggest that any Cherokee owners file comments with the FAA echoing these thoughts, or hopefully expanding on them. The comment period ends Dec. 22, 2017, so we have just over a month. To comment, go to the regulations dot gov site and enter 'FAA-2017-1059' in the search bar (that's the Docket number).

Contacting AOPA for help might be a good idea, too.

Posted by: TED CANNADAY | November 10, 2017 6:34 AM    Report this comment

Many more have had the problem but it goes unnoticed during a normal annual, there is no way to see it unless the gas tank is removed. The real number of spars out there flying with severe corrosion is not known but may be significant especially for coastal aircraft and those parked outside. The proposed AD seems a most reasonable way to get the spar checked without tearing the tank out at every annual.

Posted by: bruce postlethwait | November 10, 2017 12:06 PM    Report this comment

When I was looking for a good used Cherokee 180, I had concerns about wing spar corrosion so when I would go look at a plane. I would often ask the owner about Piper Service Bulletin 1006 were the wing tanks were removed, and the spar would be inspected and chemically treated to prevent corrosion. Often the owners would look at me with a puzzled look, most of them didn't have a clue what I was talking about! Needless to say I didn't purchase any of those aircraft. So I think an AD with inspection plates is a fantastic idea.

Posted by: Barry Glisson | November 10, 2017 1:45 PM    Report this comment

"Only two (2) airplanes out of a fleet of 11,476 Cherokees have been found to have this corrosion problem" Correct, except you forgot that not all 11,476 airplanes have been inspected.

Posted by: Ken Keen | November 12, 2017 8:28 AM    Report this comment

The Cherokee wing spar corrosion issue has been known for decades. When the FAA says it was based on 2 reports, it means they had 2 that actually got SDRs filled out and filed. There's a lot more that have been scrapped over the years for this issue, and more to come if the AD becomes active. I'm curious though how well the inspection panels will work, given that typically the problem seems to start with dissimilar metal corrosion between the screws and nut plates used for the fuel tanks and the aluminum extruded spar, and unless you have a really really good borescope no access panel is going to let you see that area.

Posted by: Roger Braun | November 16, 2017 2:03 PM    Report this comment

*see that area without removing the fuel tank.

Posted by: Roger Braun | November 16, 2017 2:04 PM    Report this comment

I wonder how many people will still think this AD is unnecessary if it is found that the 4/4/18 ERAU incident is a result of spar corrosion. No, we don't know why the wing departed the aircraft yet, but I'm sure I'm not the only one that suspected corrosion and thought of this AD immediately after learning of the major structural failure of a coastal operated PA-28.

I don't understand why anyone would NOT want to do this. I'd rather find corrosion and have to scrap a whole wing (or two), than suffer the same fate as the two unfortunate souls in Florida. Seems like a no-brainer to me.

Posted by: John (Dizzy) Phunt | April 11, 2018 8:16 AM    Report this comment

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