Fuel Tank Placards

[cessna170bdriver]

Even though I no longer use mogas I still have the EAA STC placards for fuel type. For quantity, I used Dymo lables. Yes they look cheesy, but you have to either be fueling or inspecting the airplane to notice them, and they've survived about 25 annual inspections.

[n2582d]

Cessna Single Engine Service Bulletin SEB92-27, in addition to vented fuel caps, calls for placard p/n 000001 "Avgas Placard - GAMA (80 100LL 100)". That placard is good for everything from the 140A through some 182's so it probably does not include fuel capacity. The placard costs around $4.00 from Cessna.

[GAHorn]

You can write the information by the gas filler neck with a Pilot Permanent Marker and it will meet the rule.
"Fuel/Avgas/80/87Min Octane 21 U.S. Gals" (Typical A or B model)

I suggest you PRINT it, as most kids that work the line these days don't know how to read longhand.

[blueldr]

George, as you well know I have used and advocated mogas in the super hi tech Coninental C-145/O-300 engine for years. However, I have always maintained that MMO is not my thing and pretty much a waste of money. But even if it doesn't do anything for the engine, it probably wont hurt it if you don't dose it too heavilly.

[GAHorn]

OK... I'll allow myself to be "outed".... Just last weekend I bought a go kart for the grandkids. I fueled it up with ordinary ethanol-laced mogas and it ran fine for the entire weekend...but only because I also put about 4 oz each of MMO and Stabil into the half-gallon tank. (It's a chineese Honda-copy go kart and probably thought the atmosphere in central Texas too clean, so I dirtied up the sorry fuel even more, to make it feel at home.)

[n2582d]

I’m puzzled by the apparent inconsistency between CAR 3 rules which stipulate that the placard at the fuel tank filler should read usable fuel quantity and what George has been saying throughout this thread, which is that total capacity— 21 gallons— is what should be printed. CAR 3 went through at least 14 amendments so I thought that maybe the rule changed in one of these revisions but the first version of 3.767 (a) matches the last in that the word “usable” is included. Mike chronicles his C-170A restoration here. On page 24 of that thread he has a picture of what he duplicated from the trace of the original stencil — 21 gallons, not the 18.5 gallons that TCDS lists for usable.

The early C-172’s, also certified under CAR 3 and with fuel tanks identical to the C-170A and B, have a TCDS required placard near the fuel tank filler which should read, “Cap. 21 U.S. gal.” It appears that someone at Cessna wasn’t reading the rules when they made the stencil for the C-170 A/B.

[voorheesh]

The Cessna engineers who were responsible for that placard likely reasoned that the 21 gallon capacity of their fuel tank included the useable fuel. Therefore, the regulation was met. The 21 gallon placard reduces potential for ambiguity or confusion as to the actual capacity of a Cessna 170 fuel system. That’s my guess.

[Bruce Fenstermacher]

Interesting catch Gary. Here are CAR 4, 3, FAR 23 and 25 wording regarding fuel placards. Note no quantity is required for aircraft certified under FAR 23 and 25.

CAR 4

Car 4.png (11.5 KiB) Viewed 100311 times

CAR 3

Car 3.png (20.05 KiB) Viewed 100311 times

FAR 23
Sec. 23.1557 — Miscellaneous markings and placards.
(c) Fuel, oil, and coolant filler openings. The following apply:
(1) Fuel filler openings must be marked at or near the filler cover with—
(i) For reciprocating engine-powered airplanes—
(A) The word “Avgas”; and
(B) The minimum fuel grade.

FAR 25
§ 25.1557 Miscellaneous markings and placards.
(b) Powerplant fluid filler openings. The following apply:
(1) Fuel filler openings must be marked at or near the filler cover with—
(i) The word “fuel”;
(ii) For reciprocating engine powered airplanes, the minimum fuel grade;

[voorheesh]

Based on what I have witnessed over the years, this little disparity doesn’t surprise me at all. Nothing is fool proof. Cessna must have either missed or misinterpreted the rule. If the CAA sent inspectors to monitor manufacturing in the 40s and 50s, I guess this wasn’t important enough to get their attention or more likely, they missed it too. Hopefully, we’re not going to suggest everyone change their placards

The idea of putting a “useable fuel” placard atop a fuel tank doesn’t make much sense. Why would you need to be reminded of useable fuel up on a ladder filling your tank? You need to know about useable fuel when planning a flight or enroute if you are concerned with what is remaining. That is information in a flight manual or TCDS. Interesting that it’s been brought up but not a big deal IMO.

[Bruce Fenstermacher]

I've spent some quality web searching time looking for the answer to the question, what and I missing here. What is missing in general is besides the CARs and FARs, the specific aircraft and model AFM, POH or TCDS may specify a placard at the fuel filler opening. Apparently Mooneys are a good example fo this. Some also might require the info on the cap and not the opening. Some might state usable fuel quantity is required others total capacity. I don't have the time to research every aircraft model. However, there are no additional fuel filler opening or cap placard requirements in any model Cessna 170. As always is the case, I may still have missed some CAR or FAR that effects a 170 but at this point I doubt it.

As has been brought out in many forum discussions on the subject, I was always told the fuel opening or cap placards were for the fuelers, not the pilots. And so capacity makes much more sense than usable fuel information. In many aircraft, such as the Piper Cub, it is the same. And as pointed out it doesn't hurt to have both there even though a usable fuel placard may be required someplace else such as the fuel selector.

It just occurred to me. If the placard is for fuelers, Usable Fuel is the number they want. Since by definition Unusable fuel is that fuel that can not be used normally in operations. So the most fuel a fuel can hope to pump into a tank is the Usable Fuel Capacity. If they blindly try to pump 21 gal. in a 170A/B tank they will be dumping at least 2-1/2 gal. overboard. CAR 3 is an improvement, not a mistake. The absence of any capacity requirement in the FARs must then be the Feds reaction to indecision which is better and safer. Makes perfect sense.

Harlow observes there doesn't seem to be much interest one way or another and certainly I agree the subject doesn't come up to the level of a good MMO discussion. But besides this thread, there are lengthy discussions on Pilots of America, Mooney and Cessna 182 forums which is where I stopped looking. I probably could have found a discussion in any type forum.

As for me, I've already researched which CAR my Vagabond is certified which is CAR 3 same as the 170. I'll be running out to the airport today to make sure my Vag is placarded correctly with Usable Fuel Capacity. Why, because I will feel much safer knowing I'm in complete compliance with the CARs and FARS, but more importantly daring anyone in authority to question my placard wording .

[voorheesh]

Good for you Bruce! The only thing I have to add is my sense that the FAA decision on how to label a fuel cap/opening was probably not based on any extensive analysis. It needed to have a placard. Someone in authority very likely had a personal preference on the subject. It happened. The FAA is a hierarchy structured like the Military and decisions occur in an uphill direction, sometimes without a clear explanation or reason. Proposed regulations such as CAR 3 are then subject to public comment (I believe occurred back then) and rule making procedure and things slip in unnoticed. Once enacted, end users try and comply occasionally to make errors.

The FAA IMO, is a quality agency/organization that is unquestionably the leader in aviation safety, providing the basic framework within which we operate. They are also an amazing employer providing high level support to the workers who write or approve this stuff. But how many times did I hear a colleague ask “What? Who came up with this?” “Doesn’t make sense!” You are to be commended for your attention to doing the right thing which is also found throughout the International Cessna 170 organization.

[GAHorn]

Relying upon memory only…. but any tank…be it oil, hydraulic, fuel, or whatever…. at it’s filler…should be labelled as to tank quantity …not useable…. and grade and type.

The interior placard…for example at the fuel selector valve….should read USEABLE fuel.

Bruce, I do not agree with the statement that “if the placard is for fuelers that useable fuel is the number they want…since by definition …yada yada yada” …. because that scenario you posited does not inform a refueler… who is trying to fill a tank….which may be emptied also of “drainable” fuel…in addition to what was “useable”.

So… I believe the tank filler placard should include total capacity….but the cockpit placard should indicate useable fuel.

[DaveF]

I got these from an online sticker printer. They’re cheap and have held up better than I expected. I have a Lycoming O-360, hence the octane rating.