766 

14 CFR Ch. I (1–1–19 Edition) 

§ 36.1 

restricted categories, the following 
terms have the specified meanings: 

(1) 

Stage 1 noise level 

means a takeoff, 

flyover, or approach noise level greater 
than the Stage 2 noise limits pre-
scribed in section H36.305 of appendix H 
of this part, or a flyover noise level 
greater than the Stage 2 noise limits 
prescribed in section J36.305 of appen-
dix J of this part. 

(2) 

Stage 1 helicopter 

means a heli-

copter that has not been shown under 
this part to comply with the takeoff, 
flyover, and approach noise levels re-
quired for Stage 2 helicopters as pre-
scribed in section H36.305 of appendix H 
of this part, or a helicopter that has 
not been shown under this part to com-
ply with the flyover noise level re-
quired for Stage 2 helicopters as pre-
scribed in section J36.305 of appendix J 
of this part. 

(3) 

Stage 2 noise level 

means a takeoff, 

flyover, or approach noise level at or 
below the Stage 2 noise limits pre-
scribed in section H36.305 of appendix H 
of this part, or a flyover noise level at 
or below the Stage 2 limit prescribed in 
section J36.305 of appendix J of this 
part. 

(4) 

Stage 2 helicopter 

means a heli-

copter that has been shown under this 
part to comply with Stage 2 noise lim-
its (including applicable tradeoffs) pre-
scribed in section H36.305 of appendix H 
of this part, or a helicopter that has 
been shown under this part to comply 
with the Stage 2 noise limit prescribed 
in section J36.305 of appendix J of this 
part. 

(5) A ‘‘Stage 3 noise level’’ means a 

takeoff, flyover, or approach noise 
level at or below the Stage 3 noise lim-
its prescribed in section H36.305 of ap-
pendix H of this part, or a flyover noise 
level at or below the Stage 3 noise 
limit prescribed in section J36.305 of 
appendix J of this part. 

(6) A ‘‘Stage 3 helicopter’’ means a 

helicopter that has been shown under 
this part to comply with the Stage 3 
noise limits (including applicable 
tradeoffs) prescribed in section H36.305 
of appendix H of this part, or a heli-
copter that has been shown under this 
part to comply with the Stage 3 noise 
limit prescribed in section J36.305 of 
appendix J of this part. 

(7) 

Maximum normal operating RPM 

means the highest rotor speed cor-
responding to the airworthiness limit 
imposed by the manufacturer and ap-
proved by the FAA. Where a tolerance 
on the highest rotor speed is specified, 
the maximum normal operating rotor 
speed is the highest rotor speed for 
which that tolerance is given. If the 
rotor speed is automatically linked 
with flight condition, the maximum 
normal operating rotor speed cor-
responding with the reference flight 
condition must be used during the 
noise certification procedure. If rotor 
speed can be changed by pilot action, 
the highest normal operating rotor 
speed specified in the flight manual 
limitation section for reference condi-
tions must be used during the noise 
certification procedure. 

(i) For the purpose of showing com-

pliance with this part for tiltrotors, 
the following terms have the specified 
meanings: 

Airplane mode 

means a configuration 

with nacelles on the down stops (axis 
aligned horizontally) and rotor speed 
set to cruise revolutions per minute 
(RPM). 

Airplane mode RPM 

means the lower 

range of rotor rotational speed in RPM 
defined for the airplane mode cruise 
flight condition. 

Fixed operation points 

mean des-

ignated nacelle angle positions selected 
for airworthiness reference. These are 
default positions used to refer to nor-
mal nacelle positioning operation of 
the aircraft. The nacelle angle is con-
trolled by a self-centering switch. 
When the nacelle angle is 0 degrees 
(airplane mode) and the pilot moves 
the nacelle switch upwards, the na-
celles are programmed to automati-
cally turn to the first default position 
(for example, 60 degrees) where they 
will stop. A second upward move of the 
switch will tilt the nacelle to the sec-
ond default position (for example, 75 
degrees). Above the last default posi-
tion, the nacelle angle can be set to 
any angle up to approximately 95 de-
grees by moving the switch in the up or 
down direction. The number and posi-
tion of the fixed operation points may 
vary on different tiltrotor configura-
tions. 

VerDate Sep<11>2014 

12:50 Apr 30, 2019

Jkt 247046

PO 00000

Frm 00776

Fmt 8010

Sfmt 8010

Y:\SGML\247046.XXX

247046

spaschal on DSK3GDR082PROD with CFR