Aircraft
Certification Service Washington, DC U.S. Department of Transportation Federal Aviation Administration
CE-11-13
January 5, 2011
This is information only. Recommendations
aren’t mandatory.
Introduction
This Special Airworthiness Information Bulletin (SAIB) alerts you,
owners and operators of all Piper Aircraft, Inc. PA-28, PA-32 and PA-34
models, of potential corrosion on the wing front spar at the fuselage
attach fitting, at the landing gear attach point, and behind the
leading edge fuel tank. This also alerts you of our recommendation to
incorporate Piper Service Bulletin (SB) 1006 as mitigating action.
At this time, this airworthiness concern has not been determined to be
an unsafe condition that would warrant AD action under Title 14 of the
Code of Federal Regulations (14 CFR) part 39.
Background
Aircraft may develop corrosion during their lifetime. Some of the
variables involved in the probability of corrosion development are:
potential increases with calendar time / age
potential increases with incompatible materials (e.g., aluminum and steel)
potential increases in certain environments (e.g., high moisture or salt water)
potential decreases with adequate protective coatings (e.g., zinc chromate primer)
potential decreases with adequate inspection
This information is presented in
response to service data showing extensive corrosion on the wing front
spar at the fuselage attach fitting, at the landing gear attach point,
and behind the leading edge fuel tank of Piper PA-28 and PA-32
aircraft. See Figure 1 as an example. Due to similarity of design, the
PA-34 is also susceptible to this corrosion. Note: The landing gear
attach point configuration will vary, particularly between the fixed
and retractable gear models. An example of the area of concern for the
landing gear attachment is where the bracket Piper part number 95643-06
/ -07 attaches to the front spar on the PA-28R aircraft.
Piper SB 1006 was issued in 1997 to address multiple areas of the wing,
including the forward spar, on certain PA-28 and PA-32 aircraft.
Production aircraft after the SB 1006 had zinc chromate primer added
for corrosion protection. No data was available whether the applicable
SB had been completed on the reported aircraft. Note: EASA issued AD
2005-0032 requiring SB 1006.
The FAA recommends that owners and operators incorporate the
actions in Piper SB 1006 based on the effectivity of the SB. Due to
similarity of design (steel components mating to aluminum spar) and
since improper maintenance or painting procedures have been a
contributing factor in past service reports, all PA-28, PA-32, and
PA-34 aircraft are susceptible to this corrosion development.
Therefore, the inspections in the SBs should be implemented for all
PA-28, PA-32, and PA-34 models. We recommend that all the actions be
taken within 100 hours. We further recommend inspection and
incorporation as soon as feasible, but no more than 100 hours, for
those aircraft at higher risk due to age, environment, lack of
protective coatings, etc., as discussed above.
If damage is found, a Malfunction / Defect Report or Service Difficulty
Report (SDR) should be filed. The SDR system is available at
http://av-info.faa.gov/sdrx/. There are currently no established
allowable limits on the subject parts so repair or replacement will be
necessary if damage is found.
For Further Information Contact
Gregory K. (“Keith”) Noles, Aerospace Engineer, Atlanta ACO, 1701
Columbia Ave., College Park, GA 30337; phone: (404) 474-5551; fax:
(404) 474-5606; email: gregory.noles@faa.gov
For Related Service Information Contact
Piper Aircraft Inc., 2926 Piper Drive, Vero Beach, Florida, 32960; website: http://www.piper.com/
