841 

Federal Aviation Administration, DOT 

Pt. 36, App. K 

corresponding to the airworthiness limit im-
posed by the manufacturer. For configura-
tions for which the rotor speed automati-
cally links with the flight condition, use the 
maximum normal operating rotor speed cor-
responding with the reference flight condi-
tion. For configurations for which the rotor 
speed can change by pilot action, use the 
highest normal rotor speed specified in the 
flight manual limitation section for the ref-
erence conditions. 

K6.2 Takeoff Reference Procedure. 

The take-

off reference flight procedure is as follows: 

(a) A constant takeoff configuration must 

be maintained, including the nacelle angle 
selected by the applicant; 

(b) The tiltrotor power must be stabilized 

at the maximum takeoff power cor-
responding to the minimum installed en-
gine(s) specification power available for the 
reference ambient conditions or gearbox 
torque limit, whichever is lower. The 
tiltrotor power must also be stabilized along 
a path starting from a point located 1,640 
feet (500 m) before the flight path reference 
point, at 65 ft (20 m) above ground level; 

(c) The nacelle angle and the cor-

responding best rate of climb speed, or the 
lowest approved speed for the climb after 
takeoff, whichever is the greater, must be 
maintained throughout the takeoff reference 
procedure; 

(d) The rotor speed must be stabilized at 

the maximum normal operating RPM certifi-
cated for takeoff; 

(e) The weight (mass) of the tiltrotors 

must be the maximum takeoff weight (mass) 
as requested for noise certification; and 

(f) The reference takeoff flight profile is a 

straight line segment inclined from the 
starting point 1,640 feet (500 m) before to the 
center noise measurement point and 65 ft (20 
m) above ground level at an angle defined by 
best rate of climb and the speed cor-
responding to the selected nacelle angle and 
for minimum specification engine perform-
ance. 

K6.3 Flyover Reference Procedure. 

The fly-

over reference flight procedure is as follows: 

(a) The tiltrotor must be stabilized for 

level flight along the centerline flyover 
flight path and over the noise measurement 
reference point at an altitude of 492 ft (150 m) 
above ground level; 

(b) A constant flyover configuration se-

lected by the applicant must be maintained; 

(c) The weight (mass) of the tiltrotor must 

be the maximum takeoff weight (mass) as re-
quested for noise certification; 

(d) In the VTOL/Conversion mode: 
(1) The nacelle angle must be at the au-

thorized fixed operation point that is closest 
to the shallow nacelle angle certificated for 
zero airspeed; 

(2) The airspeed must be 0.9V

CON

and 

(3) The rotor speed must be stabilized at 

the maximum normal operating RPM certifi-
cated for level flight. 

K6.4 Approach Reference Procedure. 

The ap-

proach reference procedure is as follows: 

(a) The tiltrotor must be stabilized to fol-

low a 6.0 degree approach path; 

(b) An approved airworthiness configura-

tion in which maximum noise occurs must be 
maintained; 

(1) An airspeed equal to the best rate of 

climb speed corresponding to the nacelle 
angle, or the lowest approved airspeed for 
the approach, whichever is greater, must be 
stabilized and maintained; and 

(2) The tiltrotor power during the approach 

must be stabilized over the flight path ref-
erence point, and continue as if landing; 

(c) The rotor speed must be stabilized at 

the maximum normal operating RPM certifi-
cated for approach; 

(d) The constant approach configuration 

used in airworthiness certification tests, 
with the landing gear extended, must be 
maintained; and 

(e) The weight (mass) of the tiltrotor at 

landing must be the maximum landing 
weight (mass) as requested for noise certifi-
cation. 

Section K7 Test Procedures 

K7.1 

[Reserved] 

K7.2 

The test procedures and noise meas-

urements must be conducted and processed 
to yield the noise evaluation measure des-
ignated in section K2 of this appendix. 

K7.3 

If either the test conditions or test 

procedures do not comply to the applicable 
noise certification reference conditions or 
procedures prescribed by this part, the appli-
cant must apply the correction methods de-
scribed in section H36.205 of Appendix H of 
this part to the acoustic test data measured. 

K7.4 

Adjustments for differences between 

test and reference flight procedures must not 
exceed: 

(a) For takeoff: 4.0 EPNdB, of which the 

arithmetic sum of delta 1 and the term 

¥

7.5 

log (QK/QrKr) from delta 2 must not in total 
exceed 2.0 EPNdB; 

(b) For flyover or approach: 2.0 EPNdB. 

K7.5 

The average rotor RPM must not vary 

from the normal maximum operating RPM 
by more than 

±

1.0 percent throughout the 10 

dB-down time interval. 

K7.6 

The tiltrotor airspeed must not vary 

from the reference airspeed appropriate to 
the flight demonstration by more than 

±

5 kts 

(

±

9 km/h) throughout the 10 dB-down time 

interval. 

K7.7 

The number of level flyovers made 

with a head wind component must be equal 
to the number of level flyovers made with a 
tail wind component. 

K7.8 

The tiltrotor must operate between 

±

10 degrees from the vertical or between 

±

65 

feet (

±

20 m) lateral deviation tolerance, 

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