649 

Federal Aviation Administration, DOT 

§ 29.1165 

§ 29.1147

Mixture controls. 

(a) If there are mixture controls, 

each engine must have a separate con-
trol, and the controls must be arranged 
to allow— 

(1) Separate control of each engine; 

and 

(2) Simultaneous control of all en-

gines. 

(b) Each intermediate position of the 

mixture controls that corresponds to a 
normal operating setting must be iden-
tifiable by feel and sight. 

§ 29.1151

Rotor brake controls. 

(a) It must be impossible to apply the 

rotor brake inadvertently in flight. 

(b) There must be means to warn the 

crew if the rotor brake has not been 
completely released before takeoff. 

§ 29.1157

Carburetor air temperature 

controls. 

There must be a separate carburetor 

air temperature control for each en-
gine. 

§ 29.1159

Supercharger controls. 

Each supercharger control must be 

accessible to— 

(a) The pilots; or 
(b) (If there is a separate flight engi-

neer station with a control panel) the 
flight engineer. 

§ 29.1163

Powerplant accessories. 

(a) Each engine mounted accessory 

must— 

(1) Be approved for mounting on the 

engine involved; 

(2) Use the provisions on the engine 

for mounting; and 

(3) Be sealed in such a way as to pre-

vent contamination of the engine oil 
system and the accessory system. 

(b) Electrical equipment subject to 

arcing or sparking must be installed, 
to minimize the probability of igniting 
flammable fluids or vapors. 

(c) If continued rotation of an engine- 

driven cabin supercharger or any re-
mote accessory driven by the engine 
will be a hazard if they malfunction, 
there must be means to prevent their 
hazardous rotation without interfering 
with the continued operation of the en-
gine. 

(d) Unless other means are provided, 

torque limiting means must be pro-

vided for accessory drives located on 
any component of the transmission and 
rotor drive system to prevent damage 
to these components from excessive ac-
cessory load. 

[Doc. No. 5084, 29 FR 16150, Dec. 3, 1964, as 
amended by Amdt. 29–22, 49 FR 6850, Feb. 23, 
1984; Amdt. 29–26, 53 FR 34219, Sept. 2, 1988] 

§ 29.1165

Engine ignition systems. 

(a) Each battery ignition system 

must be supplemented with a generator 
that is automatically available as an 
alternate source of electrical energy to 
allow continued engine operation if 
any battery becomes depleted. 

(b) The capacity of batteries and gen-

erators must be large enough to meet 
the simultaneous demands of the en-
gine ignition system and the greatest 
demands of any electrical system com-
ponents that draw from the same 
source. 

(c) The design of the engine ignition 

system must account for— 

(1) The condition of an inoperative 

generator; 

(2) The condition of a completely de-

pleted battery with the generator run-
ning at its normal operating speed; and 

(3) The condition of a completely de-

pleted battery with the generator oper-
ating at idling speed, if there is only 
one battery. 

(d) Magneto ground wiring (for sepa-

rate ignition circuits) that lies on the 
engine side of any firewall must be in-
stalled, located, or protected, to mini-
mize the probability of the simulta-
neous failure of two or more wires as a 
result of mechanical damage, electrical 
fault, or other cause. 

(e) No ground wire for any engine 

may be routed through a fire zone of 
another engine unless each part of that 
wire within that zone is fireproof. 

(f) Each ignition system must be 

independent of any electrical circuit 
that is not used for assisting, control-
ling, or analyzing the operation of that 
system. 

(g) There must be means to warn ap-

propriate crewmembers if the malfunc-
tioning of any part of the electrical 

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