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519 

Federal Aviation Administration, DOT 

§ 27.753 

(d) 

Operation tests. The proper func-

tioning of the retracting mechanism 
must be shown by operation tests. 

(e) 

Position indicator. There must be a 

means to indicate to the pilot when the 
gear is secured in the extreme posi-
tions. 

(f) 

Control.  The location and oper-

ation of the retraction control must 
meet the requirements of §§ 27.777 and 
27.779. 

(g) 

Landing gear warning. An aural or 

equally effective landing gear warning 
device must be provided that functions 
continuously when the rotorcraft is in 
a normal landing mode and the landing 
gear is not fully extended and locked. 
A manual shutoff capability must be 
provided for the warning device and the 
warning system must automatically 
reset when the rotorcraft is no longer 
in the landing mode. 

[Amdt. 27–21, 49 FR 44434, Nov. 6, 1984] 

§ 27.731

Wheels. 

(a) Each landing gear wheel must be 

approved. 

(b) The maximum static load rating 

of each wheel may not be less than the 
corresponding static ground reaction 
with— 

(1) Maximum weight; and 
(2) Critical center of gravity. 
(c) The maximum limit load rating of 

each wheel must equal or exceed the 
maximum radial limit load determined 
under the applicable ground load re-
quirements of this part. 

§ 27.733

Tires. 

(a) Each landing gear wheel must 

have a tire— 

(1) That is a proper fit on the rim of 

the wheel; and 

(2) Of the proper rating. 
(b) The maximum static load rating 

of each tire must equal or exceed the 
static ground reaction obtained at its 
wheel, assuming— 

(1) The design maximum weight; and 
(2) The most unfavorable center of 

gravity. 

(c) Each tire installed on a retract-

able landing gear system must, at the 
maximum size of the tire type expected 
in service, have a clearance to sur-
rounding structure and systems that is 
adequate to prevent contact between 

the tire and any part of the structure 
or systems. 

[Doc. No. 5074, 29 FR 15695, Nov. 24, 1964, as 
amended by Amdt. 27–11, 41 FR 55469, Dec. 20, 
1976] 

§ 27.735

Brakes. 

For rotorcraft with wheel-type land-

ing gear, a braking device must be in-
stalled that is— 

(a) Controllable by the pilot; 
(b) Usable during power-off landings; 

and 

(c) Adequate to— 
(1) Counteract any normal unbal-

anced torque when starting or stopping 
the rotor; and 

(2) Hold the rotorcraft parked on a 

10-degree slope on a dry, smooth pave-
ment. 

[Doc. No. 5074, 29 FR 15695, Nov. 24, 1964, as 
amended by Amdt. 27–21, 49 FR 44434, Nov. 6, 
1984] 

§ 27.737

Skis. 

The maximum limit load rating of 

each ski must equal or exceed the max-
imum limit load determined under the 
applicable ground load requirements of 
this part. 

F

LOATS AND

H

ULLS

 

§ 27.751

Main float buoyancy. 

(a) For main floats, the buoyancy 

necessary to support the maximum 
weight of the rotorcraft in fresh water 
must be exceeded by— 

(1) 50 percent, for single floats; and 
(2) 60 percent, for multiple floats. 
(b) Each main float must have 

enough water-tight compartments so 
that, with any single main float com-
partment flooded, the main floats will 
provide a margin of positive stability 
great enough to minimize the prob-
ability of capsizing. 

[Doc. No. 5074, 29 FR 15695, Nov. 24, 1964, as 
amended by Amdt. 27–2, 33 FR 963, Jan. 26, 
1968] 

§ 27.753

Main float design. 

(a) 

Bag floats. Each bag float must be 

designed to withstand— 

(1) The maximum pressure differen-

tial that might be developed at the 
maximum altitude for which certifi-
cation with that float is requested; and 

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520 

14 CFR Ch. I (1–1–24 Edition) 

§ 27.755 

(2) The vertical loads prescribed in 

§ 27.521(a), distributed along the length 
of the bag over three-quarters of its 
projected area. 

(b) 

Rigid floats. Each rigid float must 

be able to withstand the vertical, hori-
zontal, and side loads prescribed in 
§ 27.521. These loads may be distributed 
along the length of the float. 

§ 27.755

Hulls. 

For each rotorcraft, with a hull and 

auxiliary floats, that is to be approved 
for both taking off from and landing on 
water, the hull and auxiliary floats 
must have enough watertight compart-
ments so that, with any single com-
partment flooded, the buoyancy of the 
hull and auxiliary floats (and wheel 
tires if used) provides a margin of posi-
tive stability great enough to minimize 
the probability of capsizing. 

P

ERSONNEL AND

C

ARGO

 

A

CCOMMODATIONS

 

§ 27.771

Pilot compartment. 

For each pilot compartment— 
(a) The compartment and its equip-

ment must allow each pilot to perform 
his duties without unreasonable con-
centration or fatigue; 

(b) If there is provision for a second 

pilot, the rotorcraft must be control-
lable with equal safety from either 
pilot seat; and 

(c) The vibration and noise charac-

teristics of cockpit appurtenances may 
not interfere with safe operation. 

§ 27.773

Pilot compartment view. 

(a) Each pilot compartment must be 

free from glare and reflections that 
could interfere with the pilot’s view, 
and designed so that— 

(1) Each pilot’s view is sufficiently 

extensive, clear, and undistorted for 
safe operation; and 

(2) Each pilot is protected from the 

elements so that moderate rain condi-
tions do not unduly impair his view of 
the flight path in normal flight and 
while landing. 

(b) If certification for night oper-

ation is requested, compliance with 
paragraph (a) of this section must be 
shown by ground or night flight tests. 

(c) A vision system with a trans-

parent display surface located in the 

pilot’s outside field of view, such as a 
head up-display, head mounted display, 
or other equivalent display, must meet 
the following requirements: 

(1) While the vision system display is 

in operation, it must compensate for 
interference with the pilot’s outside 
field of view such that the combination 
of what is visible in the display and 
what remains visible through and 
around it, allows the pilot compart-
ment to satisfy the requirements of 
paragraphs (a)(1) and (b) of this sec-
tion. 

(2) The pilot’s view of the external 

scene may not be distorted by the 
transparent display surface or by the 
vision system imagery. When the vi-
sion system displays imagery or any 
symbology that is referenced to the im-
agery and outside scene topography, 
including attitude symbology, flight 
path vector, and flight path angle ref-
erence cue, that imagery and sym-
bology must be aligned with, and 
scaled to, the external scene. 

(3) The vision system must provide a 

means to allow the pilot using the dis-
play to immediately deactivate and re-
activate the vision system imagery, on 
demand, without removing the pilot’s 
hands from the primary flight and 
power controls, or their equivalent. 

(4) When the vision system is not in 

operation it must permit the pilot 
compartment to satisfy the require-
ments of paragraphs (a)(1) and (b) of 
this section. 

[Doc. No. 5074, 29 FR 15695, Nov. 24, 1964, as 
amended by Docket FAA–2013–0485, Amdt. 27– 
48, 81 FR 90170, Dec. 13, 2016; Docket FAA– 
2016–9275, Amdt. 27–50, 83 FR 9423, Mar. 6, 
2018] 

§ 27.775

Windshields and windows. 

Windshields and windows must be 

made of material that will not break 
into dangerous fragments. 

[Amdt. 27–27, 55 FR 38966, Sept. 21, 1990] 

§ 27.777

Cockpit controls. 

Cockpit controls must be— 
(a) Located to provide convenient op-

eration and to prevent confusion and 
inadvertent operation; and 

(b) Located and arranged with re-

spect to the pilots’ seats so that there 
is full and unrestricted movement of 
each control without interference from 

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