The following are the required powerplant instruments:

1. (a) A carburetor air temperature indicator, for each engine having a preheater that can provide a heat rise in excess of 60 °F.

2. (b) A cylinder head temperature indicator, for each—

   1. (1) Air cooled engine;
   2. (2) Rotorcraft with cooling shutters; and
   3. (3) Rotorcraft for which compliance with § 27.1043 is shown in any condition other than the most critical flight condition with respect to cooling.
3. (c) A fuel pressure indicator, for each pump-fed engine.
4. (d) A fuel quantity indicator, for each fuel tank.
5. (e) A means to indicate manifold pressure for each altitude engine.
6. (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.
7. (g) An oil pressure warning device to indicate when the pressure falls below a safe value in each pressure-lubricated main rotor drive gearbox (including any gearboxes essential to rotor phasing) having an oil system independent of the engine oil system.
8. (h) An oil pressure indicator for each engine.
9. (i) An oil quantity indicator for each oil tank.
10. (j) An oil temperature indicator for each engine.

11. (k) A means to indicate the r.p.m. of each engine and at least one tachometer, as applicable, for:

    1. (1) The r.p.m. of the single main rotor;
    2. (2) The common r.p.m. of any main rotors whose speeds cannot vary appreciably with respect to each other; or
    3. (3) The r.p.m. of each main rotor whose speed can vary appreciably with respect to that of another main rotor.

12. (l) A low fuel warning device for each fuel tank which feeds an engine. This device must—

    1. (1) Provide a warning to the flightcrew when approximately 10 minutes of usable fuel remains in the tank; and
    2. (2) Be independent of the normal fuel quantity indicating system.
13. (m) Means to indicate to the flightcrew the failure of any fuel pump installed to show compliance with § 27.955.
14. (n) A means to indicate the gas temperature for each turbine engine.
15. (o) A means to enable the pilot to determine the torque of each turbine engine, if a torque limitation is established for that engine under § 27.1521(e).
16. (p) For each turbine engine, an indicator to indicate the functioning of the powerplant ice protection system.
17. (q) An indicator for the fuel filter required by § 27.997 to indicate the occurrence of contamination of the filter at the degree established by the applicant in compliance with § 27.955.
18. (r) For each turbine engine, a warning means for the oil strainer or filter required by § 27.1019, if it has no bypass, to warn the pilot of the occurrence of contamination of the strainer or filter before it reaches the capacity established in accordance with § 27.1019(a)(2).
19. (s) An indicator to indicate the functioning of any selectable or controllable heater used to prevent ice clogging of fuel system components.
20. (t) For rotorcraft for which a 30-second/2-minute OEI power rating is requested, a means must be provided to alert the pilot when the engine is at the 30-second and the 2-minute OEI power levels, when the event begins, and when the time interval expires.

21. (u) For each turbine engine utilizing 30-second/2-minute OEI power, a device or system must be provided for use by ground personnel which—

    1. (1) Automatically records each usage and duration of power at the 30-second and 2-minute OEI levels;
    2. (2) Permits retrieval of the recorded data;
    3. (3) Can be reset only by ground maintenance personnel; and
    4. (4) Has a means to verify proper operation of the system or device.
22. (v) Warning or caution devices to signal to the flight crew when ferromagnetic particles are detected by the chip detector required by § 27.1337(e).

[Doc. No. 5074, 29 FR 15695, Nov. 24, 1964, as amended by Amdt. 27-9, 39 FR 35462, Oct. 1, 1974; Amdt. 27-23, 53 FR 34214, Sept. 2, 1988; Amdt. 27-29, 59 FR 47767, Sept. 16, 1994; Amdt. 27-37, 64 FR 45095, Aug. 18, 1999; 64 FR 47563, Aug. 31, 1999; Amdt. 27-51, 88 FR 8737, Feb. 10, 2023]