R22 MR Temp Light Inoperative - legal to fly?
 

Hi and thank you all for any feedback.

I know the practical answer to this - "I wouldn't fly with a MR Temp light inoperative", but what is the position regarding regulations?

Firstly I would check the day VFR required equipment (91.205) - and the MR Temp Light is not on that list. So now I go to inoperative equipment 91.213(d) and this is where it gets a bit less clear to me. It seems to say that as long as the instrument/equipment is not required for day VFR (91.205), not "Indicated as required on the aircraft's equipment list" (the R22 POH?) and the aircraft doesn't have a MEL then it is OK to fly without the equipment being operational - as long as the pilot removes/placards (remove the bulb?) and doesn't consider it a hazard to safe flight (which is subjective).

I would conclude that legally, if it was a short flight maybe to a repair facility, you could legally fly with the MR Temp Light pulled (that is my version of removed/placarded). What do you guys think - legally?

I want to know because I want to make sure I tell my students the correct thing. And this issue doesn't just apply to the MR Temp light, what about other equipment/instruments not on the day VFR or POH lists of required equipment? (Heater, Carbon Monoxide light, VSI, etc).

Like I said the practical advice for this example would be "call the mechanics/don't fly etc" but I would appreciate some clarification on the legal issue.

Many thanks

Jay

You have a valid point, what's legal and what makes common sense it not necessarily the same.

The warning lights are explicitly mentioned in the preflight check list, and if any item from the preflight list is not a positive check, you cannot just fly and do nothing about it. Also, the EPs reference the MR temp light.

Part 91.213 (d) (4) states: "A determination is made by a pilot, [..], that the inoperative instrument or equipment does not constitute a hazard to the aircraft."

This leaves some play for interpretation, but I would argue a non-functioning MR temp light is a potential hazard to safe flying.

R22 MR TEMP indication system
 

The subject MR TEMP warning indication system must be operative.

Refer to 14 CFR § 91.213 Inoperative instruments and equipment.
...(d) Except for operations conducted in accordance with paragraph (a) or (c) of this section, a person may takeoff an aircraft in operations conducted under this part with inoperative instruments and equipment without an approved Minimum Equipment List provided—
...(2) The inoperative instruments and equipment are not—
(i) Part of the VFR-day type certification instruments and equipment prescribed in the applicable airworthiness regulations under which the aircraft was type certificated;
....

14 CFR 27 is the Certification Basis of the R22 (ref page 6 of Type Certification Data Sheet No. H10WE), and includes:
§ 27.1305 Powerplant instruments.
The following are the required powerplant instruments:
...(f) An oil temperature warning device to indicate when the temperature exceeds a safe value in each main rotor drive gearbox (including any gearboxes essential to rotor phasing) having an oil system independent of the engine oil system.

Also refer to Advisory Circular 91-67, Minimum Equipment Requirements For General Aviation Operations Under FAR Part 91 > Chapter 2. Conducting Operations Without An MEL.

Is there a gauge as well? If there is, placard the light, look at the gauge. 27.1305 is met. No?

...I had an FAA certified mechanic tell me recently that is was OK to fly a 212 with an inoperative hydraulic system because nowhere did it say in any maintenance publications that both hydraulic systems needed to be operative for flight. I just looked at him and, without trying to laugh too much, said it needed to be fixed and he got angry and demanded me to prove my point. To which I said, it ain't going anywhere until you fix it. Then he wanted to punch me in the nose.

My philosophy is if it's fitted to the aircraft it needs to be operative, unless the MMEL says otherwise. And whatever the MMEL says, or doesn't say, it always remains the prerogative of the pilot to require a defect to be rectified even if the MEL provides a waiver in the circumstances.

>Is there a gauge as well? If there is, placard the light, look at the gauge. 27.1305 is met. No?

No gauge, just the light.

Just out of curiosity. What does the "MR TEMP" light do?

@ Gullibell. Good call. Of course it is the PIC decision to fly with any malfunction even if it is in the MEL if the PIC deems it necessary for safe flight.

Nothing when it doesn't work!

:ok:

It's the main rotor gearbox over temperature light and there is no gauge.