Seat Verification and AD 2007-05-10

[pojawis]

I'm trying to determine if I have the 'original' 170 seats. I have the p/n as 0500101-43 from the parts book. Where would one find the p/n on the seat itself? I've had the seat out, but can't seem to locate a stamping or any other indication of the p/n.

[GAHorn]

I've not seen identifying part nos on early seats either. (This could be an issue at some point.) Visual inspection is the most likely way to identify the original seats.
The 170 seats are made up from welded tubular steel and have a seat area that had a rounded frontal-thigh area and a back with an oval-shape to the upper back. The early 172 seats used similar frames, but quickly went to a square-back seat.

In a related discussion...HAZARDS exist when substituting seats from other models aircraft into our 170's. Some time ago the FAA issued proprosed AD that would address the dangerous failure of seat backs. The AD is now a final rule.

NOTE: See Comment No. 4, which is where we (TIC170A) addressed our concern with regard to substituting seats from other models, and the FAA has surprised me with their disinterest. (BluElder, please note this event where the FAA has failed to regulate!) In my comment to them, I also pointed out that the seat rails/tracks of most 100 series Cessnas will accomodate each other's seats. I specifically told them that some airplanes have been so modified. But they discount it, as you can see in their decision in Comment 4.

Despite our notification to the FAA that some Cessna 170's are known to have seats from later Cessnas installed.....THEY say that THEY don't know of any.... and therefore their heads shall remain in the sand until someone is injured or killed, I suppose.

http://content.atp.com/ADs/pdf/070510.p ... 1n2e11.JS1 is a link to the AD.

The pertinent comment is (Bold added by me):

Comment Issue No. 4: Could the Seats Be Installed on Other Cessna Model Airplanes
The International Cessna 170 Association states a concern that the affected seats may be installed
on other airplanes. Many operators of Cessna airplanes find seats of later models desirable due to
features subsequently added by manufacturers, i.e., recline/height-adjustment/mechanisms. The
commenter also states that these seats usually have similar, if not identical, attachment to floor tracks
and airframes; therefore, the possibility exists for installing the seats from the same manufacturer on
other models of airplanes. These models may include Cessna 170, 170A, and 170B airplanes.
The commenter requests the applicability of the AD be specific to the crew seat model/partnumber
and not the airplane models.
Although it may be possible to install these seats on other Cessna airplane models, we are not
aware of any such installations. In addition, the modification to the seat rails and other airplane
configuration changes that would be required to install these seats would make any installation
unlikely. We will continue to monitor this situation and, if we receive information from
owner/operators indicating these seats are being installed on other airplanes, we will consider
additional rulemaking on this subject.
We are not changing the final rule AD action based on this comment.

MORAL: If you have items installed in your airplane that are not original, you may be subject to dangers that you will not be properly notified of. Sometimes owners prefer to avoid documentation of what they perceive as "minor" alterations in order to avoid paperwork issues. But failure to document is a serious matter. Improper documentation of alterations to our aircraft can work against us.

[pojawis]

Thanks, George.

If those are the qualifying condtions:

welded tubular steel and have a seat area that had a rounded frontal-thigh area and a back with an oval-shape to the upper back.

then mine are genuine 170 seats. The suspicion arose [for me] when I realized that they seem too large side-to-side.

[GAHorn]

Compare your seats to the illustration in the Illustrated Parts Catalog for your model aircraft. (Keep in mind that your seats may have had their foam cushions replaced/modified.)

[jrenwick]

Despite our notification to the FAA that some Cessna 170's are known to have seats from later Cessnas installed.....THEY say that THEY don't know of any.... and therefore their heads shall remain in the sand until someone is injured or killed, I suppose.

They might have some stringent rules about what they can use as evidence to say they "know" something, and it probably has to do with paperwork that's signed by someone with a certificate -- like a 337, maybe.

A mechanic friend of mine took over the wreckage of a PA-18 whose engine failed shortly after takeoff (no serious injuries, but the aircraft was totaled). The feds had filed a "probable cause" report, blaming the pilot: "The pilot not verifying the position of the fuel selector prior to the takeoff, resulting in the loss of engine power during initial climb due to fuel starvation."

This didn't make sense to either the pilot or the mechanic, so the mechanic tore down the carburetor. He found that the float valve had been assembled wrong by persons unknown in the past, in a way that would cause the valve to stick closed. When he tried to tell the FAA about it, they said "we can't be certain you have the carburetor from the aircraft that crashed," and refused to take any notice or action. When the mechanic filed an SDR, the FAA deep-sixed it.

As screwed up as this sounds, I think I understand why the FAA behaved this way -- the chain of custody of the evidence had been broken. They couldn't take any legal action on something they didn't have paperwork evidence for, even though it was the word of a certified AMT.

In their world, nothing is real unless it has the right paperwork!