MEL question
 

I am currently flying an AS350 part 91 in the U.S.
I looked up the Master MEL and do not find any references to caution lights except the door and generator lights. I understand that the MEL is not required when flying part 91 and only 91.205 (I think this is the right section) applies concering minimum equipment for Day VFR, etc. Now my question is this. Am I correct in assuming that it would be technically legal (although not smart) to fly the AS350 without certain caution or warning lights like the Main Gear Box Pressure or Temp light? My question relates to a situation where you landed out in the field, only to find on the restart that one of these was inop. Could you fly back to base so that it can be addressed? ps. there are no MGP or MGBT gauges. Thanks for helping me out.

I am a UK operator and have no experience nor knowledge of what happens in the USA. That said, I would be surprised if our philosophies concerning MELs were different.

The MEL lists those deficiciences or unserviceabilities with which an aircraft can be flown and under what conditions they may be carried. Fundementally, these must not affect the airworthiness or safety of the aircraft. For that reason, it is unlikely you will find any MEL entries covering the structure of the aircraft, landing gear and engine. Clearly, with these items not listed, one would not dispatch the aircraft with these sorts of deficiencies.

Basically, if the flight is being operated under rules that require the use of a MEL, and the item is not listed, then it must be serviceable.

OK then, are you saying that if it is "servicable" then it is ok to fly. I believe that it would need to be placarded inop, correct?
thanks for the response.

Or put another way, if there is no MEL then there is no facility for ANYTHING to be unserviceable. It cannot be INOP or placarded INOP. It must meet the requirements of Part 91 Basic equipment and Part 27 (in your case).

Aside from the legal issues, someone in the US did this with a 355 F2 and destroyed themselves and the aircraft and the MGB.

91.205 however covers only the most basic instruments... engine oil, etc. it says nothing about warning lights.. this is the question.



OK, I think that part 91.213 answers my question. subsection d pertaining to rotorcraft.


Thanks

Just to double-check:

The Master MEL is not usable to determine airworthieness - you need a MEL and Letter of Authorization which then make up a STC for a particular aircraft.

Without that, you need to follow 91.205, Part 27/29, and the aircraft's Equipment List which is part of its Type Certificate Data Sheet. Most likely those warning lights will be listed as "required equipment" meaning that the aircraft is not airworthy without them.

Basically, if it's required for certification, then it has to either be serviceable or covered by an MEL. No MEL means that if it's required for certification, then it has to be serviceable.
The real question, is what is required for certification??? Look at the basic aircraft flight manual. Note that this is the basic flight manual. Any STCs would obviously modify this.
If it has a caution panel diagram, or a table that lists caution panel segments, then those have to be serviceable.
If you have a fuel gage in the flight manual, and it's unserviceable, you shouldn't dispatch.
You may be able to get a temporary flight permit from your local regulatory authority, but that's a different matter.
The danger if you dispatch with these things unserviceable, and you have an accident, you can be (rightly) accused of not being within the bounds of your certificate of airworthiness, and hence your insurance is invalid...
And where do they teach you this??? Beats me. I had to learn it, and indirectly at that, while working as a certification test pilot.

To clarify the excellent answers already provided- As a *pilot* only, you can not fly an aircraft with known deficiencies, unless the specific issue is permitted by MEL. The MEL will provide conditions of permitted operation, i.e. with "door" caution panel light, you have to check every door prior to takeoff.
If you don't have one, it is a very good idea to get an MEL. It'll save you a lot of headaches.

Hint- count caution panel lights when you bring the battery up. Caution panel segments fail in both directions, dark and light. You wouldn't want to fly an unairworthy aircraft, especially as in your scenario:

"Main Gear Box Pressure or Temp light? My question relates to a situation where you landed out in the field, only to find on the restart that one of these was inop. Could you fly back to base so that it can be addressed? ps. there are no MGP or MGBT gauges."

Thanks for all the great replies. Wonder why they didn't include the part 27 in the FAR/AIM?

If the light is also listed as a limitation or a light which has an emergency procedure than it would be in the FAA approved sections of the flight manual. If the light did not work the FAA might wonder how you were planning on obiding by the limitations of the aircraft if the only thing that told you that limitation was the light.

Carry a few spare bulbs!

The reason part 27 is not published in the FAR/AIM is that it is used by very few people, and understood by even fewer. You'd also have to put in Part 23, 25, 29, 33, etc. - a whole lot of certification FARs as well.
I was already an experienced test pilot when I started working at Transport Canada, and it was at least two years before I started to fully understand the complexities and subtle points of certification.