639 

Federal Aviation Administration, DOT 

§ 27.25 

(2) The maximum weight may be in-

creased to greater than 6,000 pounds 
provided— 

(i) The number of passenger seats is 

not increased above the maximum 
number certificated on October 18, 1999, 
or 

(ii) The applicant shows compliance 

with all of the airworthiness require-
ments of this part in effect on October 
18, 1999. 

[Doc. No. 26078, 56 FR 41051, Aug. 16, 1991, as 
amended by Amdt. 27–37, 64 FR 45094, Aug. 18, 
1999] 

Subpart B—Flight 

G

ENERAL

 

§ 27.21

Proof of compliance. 

Each requirement of this subpart 

must be met at each appropriate com-
bination of weight and center of grav-
ity within the range of loading condi-
tions for which certification is re-
quested. This must be shown— 

(a) By tests upon a rotorcraft of the 

type for which certification is re-
quested, or by calculations based on, 
and equal in accuracy to, the results of 
testing; and 

(b) By systematic investigation of 

each required combination of weight 
and center of gravity if compliance 
cannot be reasonably inferred from 
combinations investigated. 

[Doc. No. 5074, 29 FR 15695, Nov. 24, 1964, as 
amended by Amdt. 27–21, 49 FR 44432, Nov. 6, 
1984] 

§ 27.25

Weight limits. 

(a) 

Maximum weight. The maximum 

weight (the highest weight at which 
compliance with each applicable re-
quirement of this part is shown) must 
be established so that it is— 

(1) Not more than— 
(i) The highest weight selected by the 

applicant; 

(ii) The design maximum weight (the 

highest weight at which compliance 
with each applicable structural loading 
condition of this part is shown); 

(iii) The highest weight at which 

compliance with each applicable flight 
requirement of this part is shown; or 

(iv) The highest weight in which the 

provisions of §§ 27.87 or 27.143(c)(1), or 
combinations thereof, are dem-

onstrated if the weights and operating 
conditions (altitude and temperature) 
prescribed by those requirements can-
not be met; and 

(2) Not less than the sum of— 
(i) The empty weight determined 

under § 27.29; and 

(ii) The weight of usable fuel appro-

priate to the intended operation with 
full payload; 

(iii) The weight of full oil capacity; 

and 

(iv) For each seat, an occupant 

weight of 170 pounds or any lower 
weight for which certification is re-
quested. 

(b) 

Minimum weight. The minimum 

weight (the lowest weight at which 
compliance with each applicable re-
quirement of this part is shown) must 
be established so that it is— 

(1) Not more than the sum of— 
(i) The empty weight determined 

under § 27.29; and 

(ii) The weight of the minimum crew 

necessary to operate the rotorcraft, as-
suming for each crewmember a weight 
no more than 170 pounds, or any lower 
weight selected by the applicant or in-
cluded in the loading instructions; and 

(2) Not less than— 
(i) The lowest weight selected by the 

applicant; 

(ii) The design minimum weight (the 

lowest weight at which compliance 
with each applicable structural loading 
condition of this part is shown); or 

(iii) The lowest weight at which com-

pliance with each applicable flight re-
quirement of this part is shown. 

(c) 

Total weight with jettisonable exter-

nal load. A total weight for the rotor-
craft with a jettisonable external load 
attached that is greater than the max-
imum weight established under para-
graph (a) of this section may be estab-
lished for any rotorcraft-load combina-
tion if— 

(1) The rotorcraft-load combination 

does not include human external cargo, 

(2) Structural component approval 

for external load operations under ei-
ther § 27.865 or under equivalent oper-
ational standards is obtained, 

(3) The portion of the total weight 

that is greater than the maximum 
weight established under paragraph (a) 
of this section is made up only of the 

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