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If dual alternators are installed, say, in a 231 or 252, must they both be working to legally fly? Hypothetical question, of course.


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If you have two alternators, and one fails in flight, you obviously can continue on to your destination.

The remaining alternator is plenty to cover the requirements for day VFR flight, and shows 3-5+ Amps, so is continuing to charge the battery. 

But, if you need to fly somewhere else (Day VFR) to address the failed alternator, can you just go, or do you need to get ferry permit?

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In the Limitations section of the AFM, there should be a Kinds of Operation Equipment List that specifies the equipment required. The limitations section of the AFM is the only part approved by the FAA, so it is binding.

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Expect that there is a limitations section that would be updated to include...

VFR, IFR, Day, and Night...

with columns of check boxes....

and rows for each alternator....

If the the alternators are required... they would be easy to find.

Kind of like the vac pump... you can get home without it... but launching into IMC would be a bad idea...

PP thoughts only, not a mechanic...

Best regards,

-a-

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19 hours ago, PT20J said:

In the Limitations section of the AFM, there should be a Kinds of Operation Equipment List that specifies the equipment required. The limitations section of the AFM is the only part approved by the FAA, so it is binding.

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This is true, except that if there is a dual alternator in a 231 it is an aftermarket alternator, and the event of failure of the backup would not be covered in the main body of the POH because the POH was written before the aftermarket item was installed. It might be in the STC for the backup alternator, of in the flight manual supplement that is supposed to be inserted in the POH, and it might also be in the STC for any mission critical navigation equipment, like a GPS/Nav comm.  There would also be the possibility that it would be in the 337 that allowed the backup alternator to be installed, because in the rare situation they are (I am aware of only one, and that is on a 262, not a true 231), the alternator would go on the vacuum pad and the vacuum system would be removed. The same is likely true of some but I don't think all 252's, that any backup alternator is an aftermarket item not covered in the POH.

Most Mooneys of that vintage do not have a true "Required Equipment" list, meaning a list in the POH of equipment that must be present and operable to fly the aircraft, with instructions about what to do and whether it is legal to fly if a particular piece of equipment is not functioning. I am aware this statement is a little controversial. There is an "Equipment List" in Mooneys of that vintage. It would list equipment present when the plane was manufactured, and might possibly be amended if some piece is installed later (some 252's, for example, might show a backup alternator on this list). However, it was intended as a weight and balance list, meaning the equipment needs to be present in the aircraft for the w & b to be true. Whether particular equipment must be operable is generally governed by the Type Certificate, the regs. on VFR and IFR equipment required for flight (91.205), and material, if any, in STCs and flight manual supplements.

Because there is an "Equipment List" in some of our POHs, and there is the confusingly similar regulatory concept of a Required Equipment list, which really is not what the Equipment List is for planes of the vintage of the 231 and 252, it has unfortunately never been crystal clear whether something listed in the POH has to be working to fly your Mooney. The answer, in my opinion, lies in the POH wording for the Equipment List, which does not say the equipment in the list has to be working.

There are also catch-all provisions in the regs about airworthiness and reckless conduct, "catch-all" meaning that the FAA can interpret them pretty much however the FAA wants to interpret them to catch all pilots. 

Generally I agree with Paul, there is no requirement I am aware of that a backup system needs to be functioning at takeoff, but I would read all the possibly applicable materials and not take anything for granted, and if a piece of equipment like a backup alternator is not working, I would fly the aircraft only long enough to get it somewhere to be repaired. The factory alternator is not the greatest, can and does fail, and takes with it all of your panel instruments, so with that in mind, would it be careless to fly in hard IMC with no other way of operating your AI than the one alternator that is known to be subject to failure? That would be a judgment call that could be monday morning quarterbacked by the FAA and might depend on what other backups you have, such as backup batteries in the electronics.

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FAR 91.213 is your guide.  

The answer is, as is often the case, “it depends.”

An example:  In the FIKI Ovation both alternators are required for flight into icing conditions.   

That requirement is not in a MEL or Kinds of Equipment list.  It is found in the AFM supplement for the TKS system as part of the STC.  

Similar type question:  Must the PIC sit in the left seat?   Probably not for most Part 91 operations.  But wait —  the 2000 Ovation with a KFC225 autopilot has a requirement buried in the AFM autopilot supplement that the PIC must be in the left front seat.  

 

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If there no requirement in the limitations section of the AFM/POH and no limitation in a AFMS supplied with the installation, then you’re good. You would still have to deactivate and label it per 91.213.

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I have been down this route with different regulatory agencies including the FAA.

If it’s installed in the aircraft, and there is no required equipment list, then from a regulatory perspective, it has to work.

The line of thought is how can a pilot determine what equipment is necessary for flight if it’s not called out in a min equipment list?

Trust me pointing out the required equipment list in part 91 won’t work.

My answer would be to not make a write up in the logbook or placard the piece of equipment as inop, and if asked, which is extremely unlikely, I mean less likely than winning the lottery. answer that it broke on the last flight.

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6 hours ago, Jerry 5TJ said:

FAR 91.213 is your guide.  

The answer is, as is often the case, “it depends.”

An example:  In the FIKI Ovation both alternators are required for flight into icing conditions.   

That requirement is not in a MEL or Kinds of Equipment list.  It is found in the AFM supplement for the TKS system as part of the STC.  

Similar type question:  Must the PIC sit in the left seat?   Probably not for most Part 91 operations.  But wait —  the 2000 Ovation with a KFC225 autopilot has a requirement buried in the AFM autopilot supplement that the PIC must be in the left front seat.  

 

those examples you cite are violations of the STC but is that the same as the FAR requirement ? 

It could be argued that the STC was not part of the original certification so it is not required for flight. 

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Just now, Cruiser said:

those examples you cite are violations of the STC but is that the same as the FAR requirement ? 

It could be argued that the STC was not part of the original certification so it is not required for flight. 

An STC is a legal change to your type certificate - it most certainly applies including any FAA approved airworthiness limitations.

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4 minutes ago, kortopates said:

An STC is a legal change to your type certificate - it most certainly applies including any FAA approved airworthiness limitations.

agreed but the A64Pilot said "The line of thought is how can a pilot determine what equipment is necessary for flight if it’s not called out in a min equipment list?" the mere fact that it is an STC negates that argument. 

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25 minutes ago, Cruiser said:

agreed but the A64Pilot said "The line of thought is how can a pilot determine what equipment is necessary for flight if it’s not called out in a min equipment list?" the mere fact that it is an STC negates that argument. 

Oh okay, but I wouldn't say the STC doesn't apply, Jerry gave a good example with the Ovation that the STC effectivey changed the required equipment list to be FIKI.

"negates that argument" is confusing.

If your saying the STC means you can't just look at the min equipment list/KOELs and stop there I completely agree and believe that was the point of Jerry's post.

Rather than saying it negates the min equip list or other limitiations in the original POH, I'd say the AFMS in the POH can modify the original POH and now the POH is incomplete without the AFMS - since its been modified by the AFMS. 

Hope I am not just adding confusing - especially if we're saying the same thing.

 

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29 minutes ago, Cruiser said:

agreed but the A64Pilot said "The line of thought is how can a pilot determine what equipment is necessary for flight if it’s not called out in a min equipment list?" the mere fact that it is an STC negates that argument. 

If the STC is installed, any limitations imposed by it wrt the min equipment list are included by extension.   I think the previous points have just been that the full limitations may not be obvious to sort out sometimes.   In this context, the installation of the 2nd alternator and requirements may depend on the nature of the installation as well as the equipment it is supporting, which make it potentially even more difficult to completely sort out.    The fact that there are STCs doesn't negate the requirements associated with them or requirements imposed by any required additions to the AFM/POH/ICA or other documents by any installed equipment, STC'ed or not.

 

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Well, before we go very far with this, who has an actual minimum equipment list for their aircraft, in the POH? The “Equipment List” in the w & b section is not such a list. Maybe they started doing them for later models, I don’t know. 

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1 hour ago, jlunseth said:

Well, before we go very far with this, who has an actual minimum equipment list for their aircraft, in the POH? The “Equipment List” in the w & b section is not such a list. Maybe they started doing them for later models, I don’t know. 

Probably no one. An MEL has to be approved by the FAA and then you end up with categories of equipment that can be inop but must be fixed within specific time frames. It was great when I flew part 135 because it allowed continued operation (sometimes) with inoperative equipment and the maintenance department got to schedule repairs according to their availability. Otherwise, under part 135 you can't fly the airplane unless everything is working and that means that maintenance is under pressure to fix squawks immediately since no one wants to take a revenue-producing aircraft off the line waiting for maintenance.

But for part 91 you have more flexibility under 91.213(d).

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This is what i have in my 94 Mooney...

I called it an MEL.   it’s title says kinds of operation equipment list.
 

Note the devices that list 2 vs. 1.

If I had a second alternator, and it was required for flight, I would probably see a number two on the chart...

-a-

 

 

461D580B-BA01-44C1-9BAF-52F4A8EC1549.jpeg

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Its not an MEL. However, it is an equipment list that requires items of equipment to be installed and operable, and under AC 91-67 and 91.213(d) that needs to be followed. I do not have such a list in my POH. My list just says what needs to be installed. The older aircraft do not have such a list, and that goes for older Cessnas and Pipers from what I have seen. I surmise that the older POHs were issued under the CARs. The effort to develop equipment lists specify what is required to be operable in an aircraft, and the effort to then develop MELs, appears to have started in the 90’s if you look at the AC. The AC has a very specific definition for an MEL. Among other things, an MEL says what needs to be done if a particular piece of equipment is inop.

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Here are a couple of pages from mine. As you can see, there are no footnotes and no requirements that anything must be operable, just that it is installed for w&b purposes. It includes, for example, the cigarette lighter. I doubt if the FAA cares that works, but they do care if it puts the CG past the forward limit (my lighter has been removed in favor of a USB charger/download port.).

Here is my point. When we have this discussion people say “look in the MEL” or “it’s in the equipment list.” I don’t believe there are any Mooneys with MELs, if there are they are very late models like the Acclaims and Ultras. As you have shown, Anthony, it has to be a “later” model to even have an equipment list of the type that requires things to be operable. Most of the fleet just flies under 91.213, and in reference to the OPs original question, that would include the 231 and as far as I know, all the 252s except maybe the aircraft made during the revival of the Encore, they might be recent enough. 73022CF9-8072-46B6-B22B-C7576972D389.thumb.jpeg.f046c239f4d17049ff6a0c003835e2d0.jpeg

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23 minutes ago, A64Pilot said:

Here is the catch with an AC, the A stands for what? That’s right they aren’t regulatory, I know the FAA has a tendency to try to act as if they were, so why don’t they  make them FAR’s?

True, but no one wants to try that defense in an enforcement action. Turning something into a reg is a very elaborate process involving public meetings, publishing for comment, and justifying the reg. There are actually three ways other than field work (actual inspections and enforcement actions) that the FAA gets its points across, the regs., opinions of counsel, and the ACs. If you get yourself into trouble, you are far better off being able to say, here, this is the AC, I followed that or at least I was trying to follow that. In addition, what the AC is doing in this particular case, is explaining the FAA's program for development of MELs and explaining that GA pilots can still legally elect to use the airworthiness rules and 91.213(d). 

For better or worse, there is a legal doctrine called "Chevron deference," that says that courts will not disturb agency's interpretations of their own regs. 91-67 is an explanation of how the FAA views its regs., so yes, it is not itself a reg., but it explains the regs and the FAA's explanation of the regs is enforceable.

Understand, I am on your side about this. Lots of people think the Chevron deference doctrine needs serious re-examination, including the US Supreme Court. The doctrine lets agencies legislate by interpretation of existing regs, basically without any real review. But right now, it is what it is. Hey, they are from the Federal government and after all, they are here to help.

What is in that AC for Mooney pilots distills down to a flow of three things, if a piece of equipment is inoperable:

1. Does it cause the aircraft to not comply with its TC, any STCs, and the general airworthiness rules under which it was certified? If so, you can't fly.

2. Does the aircraft equipment list require the equipment to be operable? If so, you can't fly. Don't worry about any MEL, you don't have one.

3. If the first and second tests are passed, then look at 91.213(d) and follow that.

Then there is #4, not in the AC, and that is, even if you pass the first three tests, can someone monday morning quarterback the operation and say it was careless and reckless to go flying into hard IMC with only one working alternator in your 231, and no vacuum system because it was removed to allow the install of a second alternator that was inop.

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jlunseth,

              A very good dissertation, I assume you have a Law background?

I was. trying to point out, I guess rather poorly that I’ve seen compliance with an AC in an enforcement action used against a person based on they are advisory only and not a reg.

It is a catch 22, and one that I’m certain that is intentional.

I’ve been pushed into compliance with an AC during a aircraft certification even when it disagrees with the reg.

Then there are the catch all’s too of course, like operating in an unsafe manner, you weren’t in violation of anything but they can still “get” you.

My favorite is your certifying a CAR 3 airplane, but the FAA has a reg that states that they can make you comply with FAR 23 if doing so will materially improve safety, that’s a judgement call by the way, one that will very from day to day.

Then you understand why the big boys have ODA’s

The FAA was at onetime trying to make manufacturers come up with MEL’s, which is pretty easy to justify, for instance 91.205 doesn’t say fuel boost pump, so can we fly without one? Those of us that are fuel injected. Of course not because the checklist requires it to be on for certain phases of flight, but the FAA wants it to be a little more obvious than that I guess.

The regs get more interesting with older aircraft, for instance my 1946 Cessna 140 doesn’t have a POH, so how do you comply with the requirement of carrying a POH in the aircraft?

 

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No you didn't do a bad job of explaining it. Pretty much everything you say is true. What I have found, though, is that the FAA really does not want to go chasing after pilots and making up charges. Charges and enforcement actions happen when there is a bad outcome of some kind, or a complaint about something a pilot did that was really stupid, like buzzing people or flying under bridges. Don't do stupid and the FAA won't come looking for you, in fact, if you get in trouble in the air their first thought will be to get you down safely, no other agenda.

There are a bunch of Master MEL's that were published. They exist for Pipers, Cessnas, and Cirrus's but there is not a Mooney specific one, the factory was probably in sleep mode when the FAA was trying to get them done. There is a generic MMEL for single engine aircraft. It is very detailed and elaborate. If anyone really wants to try, you can just google Master Minimum Equipment List, look it up, and the take it to your FSDO and confer with them so you have authorization to use it. Let's not all of us rush to the FSDO at one time though.

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On 3/5/2021 at 11:41 AM, JimB said:

Not that this helps this discussion a lot but here is a 1975 M20F

image.thumb.png.4840f2adf0bfee6e36fc01948e4c2da4.png

 

 

image.png

I don’t have a fuel pressure gauge nor was one ever installed in my 252 from the factory but yet it’s vfr and ifr certified. It calls into question why then does your require one fir vfr flying? Makes no sense to me. 

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