Manifold Pressure Gauge

[poadeleted20]

You're not an attorney. I emailed this over to a very good friend of mine who is a real attorney and I've maintained his plane for him for years.

His response:

"This wouldn't pass the "laugh test" (the judge laughs so hard he falls off the bench!) if this guy tried to use this as case law in your situation in regards to application of the FAR's you cited in the situation of someone having an instrument failure after takeoff. He clearly does not understand the issue at hand nor the applicability of case law."

That's all I got to say on that.

Good day.

Did your attorney friend give you any idea where the legal line is drawn on items required for legal airworthiness, i.e., which ones you can continue without to the planned destination and which ones require landing at the first suitable airfield? I'd be interested in any precedent cases or Chief Counsel opinions he has on point.

 

[Everskyward]

For a counter example I think (too lazy to read) that fuel gauges are required by part 23 but airplanes can be legally flown in some cases when one or more gauge is inop.

Fuel gauges can be MEL'd. I've done it.

 

[Dan Thomas]

For a counter example I think (too lazy to read) that fuel gauges are required by part 23 but airplanes can be legally flown in some cases when one or more gauge is inop.

When might that be, other than maybe on a ferry permit? It's in FAR 91 that they're required and need to be working:
91.205 Powered civil aircraft with standard category U.S. airworthiness certificates: Instrument and equipment requirements.

(a) General. Except as provided in paragraphs (c)(3) and (e) of this section, no person may operate a powered civil aircraft with a standard category U.S. airworthiness certificate in any operation described in paragraphs (b) through (f) of this section unless that aircraft contains the instruments and equipment specified in those paragraphs (or FAA-approved equivalents) for that type of operation, and those instruments and items of equipment are in operable condition.
[stuff snipped]
(9) Fuel gauge indicating the quantity of fuel in each tank.




An a further note: I see a difference between your US FAR 91.205 and our Canadian CAR 605.14 in that the CARs require the MP gauge for a variable-pitch prop as well as for turbo'd or supercharged engines. FAR 91 doesn't mention it for the variable prop.


Dan

 

[spiderweb]

Just from the standpoint of safety, it just makes sense to return if you don't feel comfortable. Of course, you'd probably be able to tell that you were producing a whole lot more than 12 inches just by noticing whether or not you'd lost power, but still--why worry? Return the plane to the FBO and rent another!

A few months back, I was renting a plane and was already on approach at BWI when I saw that the Oil Temperature gauge was pegged. Scared the living doodoo out of me, but I kept my calm. I looked at the other indicators and all seemed well. I had also noted on the squawk sheet that there had in the past been problems with the indicator (but they were supposedly remedied). BUT, I requested an immediate return. ATC was kind, even asked if I wanted to declare, and I said not at this time. It was the indicator, but I didn't feel like a wuss for returning the plane, and anyone who disagrees can, indeed, bugger the hell off.

 

[Trapper John]

FAR 23 doesn't directly control what's required for airworthy flight, just what's needed for certification. If there's a related FAR that says to put something in the limitations section of the POH requiring the gauge then this would have an actual effect on us pilots.

But wouldn't an aircraft that was not in conformance with the certification requirements be considered unairworthy? Or, if the type certificate for a particular aircraft lists a manifold pressure gauge, isn't it required to be operational for the aircraft to be airworthy? Can the POH supercede the type certificate?

I know some aircraft have minimum equipment lists and that appears to give some leeway, but for those of us that operate without a defined MEL, where does that leave us?


Trapper John

 

[Everskyward]

I know some aircraft have minimum equipment lists and that appears to give some leeway, but for those of us that operate without a defined MEL, where does that leave us?

The original question was about MP gauge which failed in flight. MELs are not used for that purpose. They give you the ability to dispatch with a certain item inop. If it fails in flight you don't pull out the MEL book and defer it right on the spot. I agree with R&W that you don't need to land as soon as possible if you know that what has failed is the gauge. That's a lot different than continuing with a failed engine which was the example someone else gave. However if someone is uncomfortable flying that way no one should give them a hard time about being a wimp or something.

 

[Trapper John]

The original question was about MP gauge which failed in flight. MELs are not used for that purpose. They give you the ability to dispatch with a certain item inop. If it fails in flight you don't pull out the MEL book and defer it right on the spot.

Let's say the MP gauge fails in flight, I land, have a mechanic check it out and he determines that it's just the gauge gone bad. If I have an MEL, and the MP gauge isn't on the list, I can go on without having it repaired, correct?

But if I don't have an MEL, I'm pretty much stuck until I get the gauge fixed, as I read it - isn't that right? I'm just trying to figure out the conflicting fuel gauge example...

I agree with R&W that you don't need to land as soon as possible if you know that what has failed is the gauge. That's a lot different than continuing with a failed engine which was the example someone else gave. However if someone is uncomfortable flying that way no one should give them a hard time about being a wimp or something.

I wasn't challenging the OP's decision, hope you didn't get that impression.


Trapper John

 

[Everskyward]

Let's say the MP gauge fails in flight, I land, have a mechanic check it out and he determines that it's just the gauge gone bad. If I have an MEL, and the MP gauge isn't on the list, I can go on without having it repaired, correct?

No that's backwards. The MP gauge would need to be on the list of items which you can defer. I have no idea whether or not you can defer a MP gauge in any airplane, though, since we don't have MP gauges.

But if I don't have an MEL, I'm pretty much stuck until I get the gauge fixed, as I read it - isn't that right? I'm just trying to figure out the conflicting fuel gauge example...

If you don't have an MEL once you land you need to get whatever it is fixed before flying again.

I wasn't challenging the OP's decision, hope you didn't get that impression.

I wasn't referring to you, I was referring to whoever it was at the FBO who gave the OP a hard time.

 

[RotorAndWing]

A little something about MEL's (Minimum Equipment List). You can go to the MMEL and see if your airplane is listed. If so you can download the list, make the applicable corrections for the way your aircraft is equipped then submit it to your FSDO for approval. Once approved this MEL is for your Registration number only and remains with the airplane until you sell the plane. If the plane is sold the MEL doesn't transfer, the new owner must submit again to the FSDO to gain approval to use the list.

http://fsims.faa.gov/PICResults.aspx?mode=Publication&doctype=MMEL

for single engine Part 91 aircraft: http://fsims.faa.gov/PICDetail.aspx?docId=589098DC96E17BD88625752400624E9F


MEL's aren't just for the big guys.

 

[spiderweb]

MEL's aren't just for the big guys.

I got a question on them in my IFR oral.

 

[gismo]

A little something about MEL's (Minimum Equipment List). You can go to the MMEL and see if your airplane is listed. If so you can download the list, make the applicable corrections for the way your aircraft is equipped then submit it to your FSDO for approval. Once approved this MEL is for your Registration number only and remains with the airplane until you sell the plane. If the plane is sold the MEL doesn't transfer, the new owner must submit again to the FSDO to gain approval to use the list.

http://fsims.faa.gov/PICResults.aspx?mode=Publication&doctype=MMEL

for single engine Part 91 aircraft: http://fsims.faa.gov/PICDetail.aspx?docId=589098DC96E17BD88625752400624E9F


MEL's aren't just for the big guys.

While that is all very true, it's my (vague) understanding that more often than not we're actually better off without a MEL and just relying on the ability to determine that a particular instrument or appliance isn't required for the type of flight we are planning, marking the failed equipment INOP, and continuing. That said, I suppose it might be possible to convince the FSDO that there are some acceptable conditions that don't meet the FAR requirements (e.g. flying a normally aspirated CS propped airplane without a MP gauge in day VFR even though the POH says the gauge is required), but I suspect this may be mostly a case of pushing ropes skyward. The thing is (as I understand it) if you have an approved MEL you must abide by it to the letter with no wiggle room so unless you included the option of flight with a defective seat belt in an unoccupied seat or a failed intercom music input etc you couldn't fly with that particular deficiency.

 

[gismo]

But wouldn't an aircraft that was not in conformance with the certification requirements be considered unairworthy?

The certification requirements of today do not generally have any direct bearing on the airworthiness of any aircraft. An aircraft certified under looser restrictions certainly need not comply with the latest set of certification rules, and in any case during the certification process the FAA often grants exceptions to the requirements based on some alternative method of achieving the same goal.

Or, if the type certificate for a particular aircraft lists a manifold pressure gauge, isn't it required to be operational for the aircraft to be airworthy?

Yes, I believe that's true but now you're talking about the type cert, not the certification rules. That's a completely different can of smelly stuff.

Can the POH supercede the type certificate?

I'm not sure what you mean. I can't think of a case where the POH directly contradicts the type certificate in a way that would allow something to be inop that's required by the type cert, but since the POH is approved somewhat independently from the type certificate it certainly seems possible that there might be something MORE restrictive in the POH limitations section (the only part of the POH that matters in this regard) than in the type certificate (and vice versa).

I know some aircraft have minimum equipment lists and that appears to give some leeway, but for those of us that operate without a defined MEL, where does that leave us?

It leaves you being required to comply with the FAR 91 (and any applicable SFARS, AD's, STC's etc), the POH limitations, and the type certificate requirements if you don't have an approved MEL for your specific aircraft. But you DO NOT have to comply with a certification requirement that's not reflected in the TC or POH limitations.

 

[RotorAndWing]

The thing is (as I understand it) if you have an approved MEL you must abide by it to the letter with no wiggle room so unless you included the option of flight with a defective seat belt in an unoccupied seat or a failed intercom music input etc you couldn't fly with that particular deficiency.

So why wouldn't you include it if it's applicable to your aircraft?

 

[gismo]

So why wouldn't you include it if it's applicable to your aircraft?

I'm not saying you couldn't, just that you might forget several things like that when you made your official MEL. Using the master MEL is certainly a good starting place but I suspect that there are things I can get away with legally now that I wouldn't have the prescience to put in a MEL.

But the more important question is what kinds of things might you get past the FSDO that aren't already allowed for a part 91 pilot on a simple GA aircraft? I'm really only guessing but I suspect the answer to that one is "not much" unless you were on very good terms with the FSDO.

 

[RotorAndWing]

I'm not saying you couldn't, just that you might forget several things like that when you made your official MEL. Using the master MEL is certainly a good starting place but I suspect that there are things I can get away with legally now that I wouldn't have the prescience to put in a MEL.

But the more important question is what kinds of things might you get past the FSDO that aren't already allowed for a part 91 pilot on a simple GA aircraft? I'm really only guessing but I suspect the answer to that one is "not much" unless you were on very good terms with the FSDO.

You can only use items listed in the MMEL, you don't get the option of writing your own items unless you want to go through a long approval process. (see preamble of the MMEL)

Your MEL once approved can be modified to add any items from the MMEL with a letter to the FSDO and a revision to your MEL.

Anything already acceptable for Part 91 operations is included irregardless of the MEL.

3. "As required by FAR" means that the listed item is subject to
certain provisions (restrictive or permissive) expressed in the
Federal Aviation Regulations operating rules. The number of
items required by the FAR must be operative. When the listed
item is not required by FAR it may be inoperative for time
specified by repair category.

 

[taters]

Did your attorney friend give you any idea where the legal line is drawn on items required for legal airworthiness, i.e., which ones you can continue without to the planned destination and which ones require landing at the first suitable airfield? I'd be interested in any precedent cases or Chief Counsel opinions he has on point.

Next time I lose a MP guage Im gonna put her down in the Hudson