Fuel drain valve installation ... fuel selector valve

[johneeb]

[rnealon1]

Thank you!

Bob

[rnealon1]

Hi George,

The copy of the STC supplied above is also available on the FAA website; that is where I came across it. Was the scrap of paper you referenced something in addition to this?

Thanks,

Bob

[GAHorn]

Hi George,

The copy of the STC supplied above is also available on the FAA website; that is where I came across it. Was the scrap of paper you referenced something in addition to this?

Thanks,

Bob

No, in fact, it was a much less “official” looking scrap, only about 6” by 2” on an orange piece of paper.

I see the FAA only required 3 months to approve this very-complicated STC.

[rnealon1]

Thanks George!

If you ever come across it I would love to get a copy for posterity.

Bob

[rnealon1]

For anyone interested I have attached the STC from the FAA which includes the second page with a list of the models covered.

Bob

[rnealon1]

To be more precise, it lists the serial numbers, only the model B is covered.

Thanks,

Bob

[n2582d]

One cannot simply download a copy of an STC and install the item in accordance with the STC - whether it’s an O-360 or a drain valve. For the C-mods STC to be valid you need authorization like this:

I can see Blueldr rolling in his grave.

In my opinion the FAA should never have issued this STC to C-mods as it is a minor alteration. How many of you have authorization to install drain valves in your main tanks? They are not original but who in their right mind would not install them as a minor alteration? OK, maybe this guy. Hmmm ... maybe I need to come up with an STC to install those tank drain valves. I could make a killing!

Screen Shot 2020-04-21 at 12.01.28 PM.png (14.1 KiB) Viewed 12018 times

One might try calling the phone number shown above if you want to go the STC route.

[rnealon1]

Hi Gary,

Thank you for the copy. I may give the number a try, although based on the date of installation this probably was not his STC.

Appreciate it.

Bob

[Bruce Fenstermacher]

FYI only B models serial 20287 which are those with the last machined aluminum fuel selector. The first 18 B models and A models had a cast Weather Head valve. The Weather Head valve does not have a plug in it. Instead just after the fuel valve is a fitting which has a plug. The problem is there is no hole directly below this plug for a quick drain valve. One would have to be drilled.

[rnealon1]

This is what is stated in the STC:

*Cessna 170B – Serial Nos. 20267 - 20999 (1952)
25000 - 25372
25373 - 26038 (1953)
26039 - 26504 (1954)
26505 - 26995 (1955)
26996 - 27169 (1956)

Bob

[GAHorn]

I acquired my drain directly from Norman Carden and the scrap of paper he included did not mention model or serial number for the STC.

I also consider the STC invalid because this is not a major alteration.

[n2582d]

George,
It looks like you've changed your opinion over the years regarding whether this is a major or minor alteration. To be fair, maybe it was more a matter of expediency in dealing with your FSDO inspector. It appears you were instrumental in getting the C170B on the AML list for this STC.

TIC170A assisted him in developing this STC so it'd be legal for our aircraft ... (Installation of valves without an STC or without some other basis of approval such as a field approval is not legal. ...

As soon as the STC holder (Skip Cardell) notifies me I'll let you all know about it. (I knew he had such an STC for the 172 and others and I had contacted him to inquire as to whether he had an STC for the 170, he didn't, so we consulted for development of the STC. I've supplied him with the technical support regarding the selector valve and the aircraft relationship status to the other STC's he has. ...

From FAR1.1: "Major alteration means an alteration not listed in the aircraft, aircraft engine, or propeller specifications...." Since this drain valve replaces an original part with different operation (a plug) it is a major alteration. I personally know a mechanic whose certificate was suspended for 90 days because he actually wrote in a logbook "I consider this a minor alteration." contrary to FAR 1.1. He was also required to attend remedial training to reinstate his certificate. ...

.. The def'n of FAR 1.1 applies to this because the selector valve drain plug conversion to a quick-drain is an alteration of a PMA'd part that should the alteration fail....will "appreciably affect....performance, engine operation..." etc., as explained by my (ordinarily very reasonable) FSDO inspector.

As the price for the STC was reasonable I purchased it but still don't feel it should have been issued by the FAA because it is a minor alteration. Take a look at Saf-Air's approval list for the CAV-110. Here they reference Supplement No. 1 as a basis for approval. In that supplement the last two columns -- for make and model installation eligibility -- reference SAF-AIR drawing SAP-1000, Rev. B, 9/11/89. This chart shows that valves with 1/8 NPT threads like the CAV-110 valve used in the fuel selector valve and 7/16-20 threads like those used in place of the drain plugs in the main tanks are approved on all models of the Cessna 170. To me that should be enough documentation to install these drains wherever they fit on C-170's with just a logbook entry. Thanks to Bob Lescoe of Saf-Air for sharing this chart, the top half of which is copied below.

SAP-1000, Click to Enlarge

[GAHorn]

That is correct... I have changed my opinion on this item. Here’s the full story:

On behalf of one of our Convention Hosts I contacted a great number of aviation mfr’s and suppliers and solicited donations for our Association to be either given as door-prizes, convention bag-fillers, or fund-raising auction items. Mr. Cardell was one of the suppliers I solicited.
When his donation was rec’d I noticed the AML did not include the 170 so I contacted him again and asked if perhaps that was a mistake and he informed me he’d never had a 170 owner ask about it, and he said his FSDO would be contacted about adding the 170. I subsequently received a call from the FSDO Mx Inspector involved inquiring about it and I sent a scan of the IPC showing 170B models had the same fuel selector valve as the early 172, and that was used as the basis of adding the 170B to the STC. That contact with the Mx Inspector brought up the discussion regarding whether or not it was a major alteration and my comments posted (which you quoted) was a regurgitation of the FAA Inspector’s position on the matter. I didn’t question the FAA at the time, but subsequently (I believe) the Inspector must have revisited the issue perhaps with the SAF-Air folks. My own FSDO-SAT is one of the pickiest I’ve ever dealt with and during lunch with one of them some years later, I brought this up and came to a different view of it.
As these forums are now approaching twenty years longevity since I created them, I’ve changed in a few other ways also.

BTW: The IA I mentioned in my previous post who was reprimanded was not involved with this drain valve issue, and I did not intend to imply that if that’s what anyone thought. That event was actually over the complete re-design and construction of an instrument panel on a C-206, which brought OKC’s attention to the personal airplane that IA owned. Several modifications he’d made on his personal 182 is what got him into trouble. To top that off... some years later when I was a designee in the DFW area, I was contacted by Del to inquire if I had any contacts with the FTW FSDO Mx folks, as he (Del) was having trouble with one of the inspectors there refusing to issue a ferry permit for a Twin Beech to be flown with the gear down for repair. When Del gave me the name of the FSDO Mx Inspector he was in disagreement with... I nearly fainted.... Same Guy as was formerly suspended with his Franken-182.

Yep. Things sometimes change....