276 

14 CFR Ch. I (1–1–19 Edition) 

§ 25.737 

(1) It must operate satisfactorily over 

the range of expected runway condi-
tions, without external adjustment. 

(2) It must, at all times, have pri-

ority over the automatic braking sys-
tem, if installed. 

(f) 

Kinetic energy capacity

—(1) 

Design 

landing stop. 

The design landing stop is 

an operational landing stop at max-
imum landing weight. The design land-
ing stop brake kinetic energy absorp-
tion requirement of each wheel, brake, 
and tire assembly must be determined. 
It must be substantiated by dynamom-
eter testing that the wheel, brake and 
tire assembly is capable of absorbing 
not less than this level of kinetic en-
ergy throughout the defined wear 
range of the brake. The energy absorp-
tion rate derived from the airplane 
manufacturer’s braking requirements 
must be achieved. The mean decelera-
tion must not be less than 10 fps

2

. 

(2) 

Maximum kinetic energy accelerate- 

stop. 

The maximum kinetic energy ac-

celerate-stop is a rejected takeoff for 
the most critical combination of air-
plane takeoff weight and speed. The ac-
celerate-stop brake kinetic energy ab-
sorption requirement of each wheel, 
brake, and tire assembly must be de-
termined. It must be substantiated by 
dynamometer testing that the wheel, 
brake, and tire assembly is capable of 
absorbing not less than this level of ki-
netic energy throughout the defined 
wear range of the brake. The energy 
absorption rate derived from the air-
plane manufacturer’s braking require-
ments must be achieved. The mean de-
celeration must not be less than 6 fps

2

. 

(3) 

Most severe landing stop. 

The most 

severe landing stop is a stop at the 
most critical combination of airplane 
landing weight and speed. The most se-
vere landing stop brake kinetic energy 
absorption requirement of each wheel, 
brake, and tire assembly must be de-
termined. It must be substantiated by 
dynamometer testing that, at the de-
clared fully worn limit(s) of the brake 
heat sink, the wheel, brake and tire as-
sembly is capable of absorbing not less 
than this level of kinetic energy. The 
most severe landing stop need not be 
considered for extremely improbable 
failure conditions or if the maximum 
kinetic energy accelerate-stop energy 
is more severe. 

(g) 

Brake condition after high kinetic 

energy dynamometer stop(s). 

Following 

the high kinetic energy stop dem-
onstration(s) required by paragraph (f) 
of this section, with the parking brake 
promptly and fully applied for at least 
3 minutes, it must be demonstrated 
that for at least 5 minutes from appli-
cation of the parking brake, no condi-
tion occurs (or has occurred during the 
stop), including fire associated with 
the tire or wheel and brake assembly, 
that could prejudice the safe and com-
plete evacuation of the airplane. 

(h) 

Stored energy systems. 

An indica-

tion to the flightcrew of the usable 
stored energy must be provided if a 
stored energy system is used to show 
compliance with paragraph (b)(1) of 
this section. The available stored en-
ergy must be sufficient for: 

(1) At least 6 full applications of the 

brakes when an antiskid system is not 
operating; and 

(2) Bringing the airplane to a com-

plete stop when an antiskid system is 
operating, under all runway surface 
conditions for which the airplane is 
certificated. 

(i) 

Brake wear indicators. 

Means must 

be provided for each brake assembly to 
indicate when the heat sink is worn to 
the permissible limit. The means must 
be reliable and readily visible. 

(j) 

Overtemperature burst prevention. 

Means must be provided in each braked 
wheel to prevent a wheel failure, a tire 
burst, or both, that may result from 
elevated brake temperatures. Addition-
ally, all wheels must meet the require-
ments of § 25.731(d). 

(k) 

Compatibility. 

Compatibility of 

the wheel and brake assemblies with 
the airplane and its systems must be 
substantiated. 

[Doc. No. FAA–1999–6063, 67 FR 20420, Apr. 24, 
2002, as amended by Amdt. 25–108, 67 FR 
70827, Nov. 26, 2002; 68 FR 1955, Jan. 15, 2003] 

§ 25.737

Skis. 

Each ski must be approved. The max-

imum limit load rating of each ski 
must equal or exceed the maximum 
limit load determined under the appli-
cable ground load requirements of this 
part. 

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