Textron has issued a mandatory service letter covering the carry through spars of almost every Cessna 210 with cantilevered wings and most operators have only 20 hours to comply. The Nov. 1 edict requires inspection of and mitigation of corrosion on the spars, which run through the ceiling of the cockpit and hold the wings. It’s not clear what prompted the all-encompassing service letter but only early 210s with struts and strutless models that were inspected under an earlier service letter for aircraft with more than 4,000 hours or those deemed to have been operated in severe service with more than 1500 hours are exempt.
Later model N and R models must be inspected within 200 hours or at the next annual. Those spars were painted at the factory before installation. The spars have to be inspected with a 10X magnifier for evidence of cracks or corrosion. Cracks ground the airplane immediately. Light corrosion can be mitigated with sanding it away. Only a certain amount of material, which varies by the location on the spar, can be removed without triggering an eddy current inspection. The inspection requires removal of the headliner, oxygen plumbing and head protection foam pads from the spars and anything else in the way of an unobscured inspection of the full strut. Inspection reports must be submitted to Textron.
Shrimp fork?
I believe that the SL was prompted by an aircraft that lost a wing in flight. The failure was traced to corrosion on the carry through section of the main spar that caused it to fracture. The inspection was also extended to all years of the 177 Cardinal, both fixed gear and retractable. In the case of the Cardinal, an Eddy Current inspection was recommended under certain conditions.
The Cardinal design is based on the 210 (indeed, the wings are the same shape, just using fewer ribs and thinner skins due to the lighter gross weight). The carry-through spar, however, is unique to the Cardinal. Another difference is the 210 had padding glued to the underside of the spar to protect occupants from bumping their head on the exposed beam. It’s thought that this padding may have trapped moisture against the spar. The Cardinal’s spar was hidden above a plastic headliner.
I talked to one pilot who flies Cardinals in pipeline patrol, and some of those airframes have well in excess of 40,000 hours on them (“…before the Hobbs broke…”), bouncing around in turbulence at low altitude. So it would seem the Cardinal structure is pretty robust. That being said, there are enough similarities in design and construction to the 210, and the inspection is not particularly onerous, that it made sense to check out the Cardinal spar as well as outlined in the earlier notice.
It seems like this new SL, aimed solely at the 210, is based upon field reports from the earlier inspections.
Yep, see https://www.atsb.gov.au/media/news-items/2019/cessna-210-carry-through-spar-failure/ for the reason for the SL.
Read with interest this last sentence of the article: “Inspection reports must be submitted to Textron.”
By what authority does Textron have to compel any action by an aircraft owner? The FAA can of course compel under FAR 39 (Airworthiness Directives). However, I don’t think a manufacturer can.
I’m in favor of any action that improves aviation safety reporting, including condition reports. However, I believe its important to understand the law and to clearly state what rights an individual owner has with relationship to another commercial entity.
It is true that this action is a little bit muddled as who is the authority here? It should be the FAA under FAR 39. However, Textron? An independent company and not a regulatory agency? Am I missing something?
This is NOT an AD; it’s a “mandatory” Service Bulletin. You can wrap your fish in it, if you like.