New ACS - Cessna Wing Spar

[WebMaster]

This is just in.

This is notification that a new Airworthiness Concern Sheet entitled Cessna Wing Spar has been released by the FAA. Comments on this ACS are due back to the FAA no later than August 30, 2010

To review this Airworthiness Concern, please see the AOPA ACS Coordination Web site at http://www.aopa.org/gta/ad/ Comments should be emailed directly to the FAA engineer listed in the ACS. Additionally, we also ask that you submit your comments to the AOPA ACS Coordination Web site. To submit your comments click on the comment submission link at the bottom of the ACS page, attach your comments in MS Word or equivalent, type the name of the concern into the subject line and press send.

[stackj]

Larry,

I went to the link... couldn't find your reference. Where have I gone wrong?

[WebMaster]

This is notification that a new Airworthiness Concern Sheet entitled Cessna Wing Spar has been released by the FAA. Comments on this ACS are due back to the FAA no later than August 30, 2010

To review this Airworthiness Concern, please see the AOPA ACS Coordination Web site at http://www.aopa.org/gta/ad/ Comments should be emailed directly to the FAA engineer listed in the ACS. Additionally, we also ask that you submit your comments to the AOPA ACS Coordination Web site. To submit your comments click on the comment submission link at the bottom of the ACS page, attach your comments in MS Word or equivalent, type the name of the concern into the subject line and press send.

Thank you for your support.

　

Sincerely,

Kristine Hartzell

Manager, Regulatory Affairs

AOPA

301-695-2086

[WebMaster]

Update


http://www.aopa.org/gta/ad/main/inde...tail&Awcid=563

[KHartzell]

http://www.aopa.org/gta/ad/main/inde...tail&Awcid=563

Here's the text of the Airworthiness Concern Sheet:
FAA Description of Airworthiness Concern
The Cessna Multi-Engine Service Letter ME78-2, dated February 13, 1978, and Airworthiness Directive (AD) 78-09-05 require a dye penetrant inspection of the rear spar cap. Dye penetrant is no longer considered acceptable for the following reasons:

(1) Neither the AD nor the Cessna Service Bulletin specifies which kind of penetrant is to be used in the inspection. Penetrant is available in
visible dye and fluorescent types along with many levels of sensitivity. So, there is variation in inspection results depending on which
combination of penetrant options used. Also, evidence shows that following up a visible dye penetrant inspection with a fluorescent
penetrant inspection can lead to reduced sensitivity in the fluorescent penetrant due to the potential mixing of the two penetrants. The reduced sensitivity makes detection of smaller cracks unlikely. See SID 57-30-02, Section 2-13-01, for clearer explanation.
(2) Cleaning the area appropriately without removing the tank is a concern since the access to the area is inadequate for proper pre- and post-cleaning.
(3) The use of penetrant materials in areas that have mating surface can create contamination for future processing; such as, painting and corrosion protective compounds. Inappropriate use of water washable penetrant materials can attract moisture that may cause corrosion.
(4) The only way to apply developer to this area is using dry or non-aqueous methods. Because of limited access, post-cleaning will cause the area to hold moisture that may cause corrosion.
(5) The eddy current equipment is already in use to do the bolthole inspections on the front spar, so cost increase should be minimal. There should be little or no clean up required of the rear spar, so no paint removal and repainting. The inspection is much quicker using eddy current.

The FAA is also considering eliminating Section II of AD 78-09-05 that states: “Airplanes found to have cracked spar caps, webs or web doublers during inspections required by the AD may be flown in accordance with FAR 21.197 to a base where the component replacement can be accomplished. When the spar cap is broken, the remaining structure will no longer meet residual strength requirements and further flight may not be safe.

At this time, the FAA has not made a determination on what type of corrective action (if any) should be taken. The resolution of this airworthiness concern could involve an Airworthiness Directive (AD) action or a Special Airworthiness Information Bulletin (SAIB), or the FAA could determine that no action is needed at this time. The initial Risk Assessment for this concern indicated that an AD or SAIB might be considered.

[WebMaster]

Originally Posted by stackj

Larry,

I went to the link... couldn't find your reference. Where have I gone wrong?

Here's a quote from the first document

FAA Description of Airworthiness Concern
The Cessna Multi-Engine Service Letter ME78-2, dated February 13, 1978, and Airworthiness Directive (AD) 78-09-05 require a dye penetrant inspection of the rear spar cap. Dye penetrant is no longer considered acceptable for the following reasons:

There is also reference to an inspection method outlined in a SID, but since we haven't seen those, I don't know how we can comply.

That's just my .02 for starters.

[Skymaster337B]

I own an Eddy Current machine that is specified in the Cessna Service Bulletin, which the AD refers to. There's a few problems not addressed either before or now. First, it is important that Cessna provide a sample that the machine can be calibrated against; there is no reference to this, nor does Cessna have a part number for the required calibration sample. Additionally, most of the bolt holes in the front spare caps are threaded, making the inspection some what subjective.