14 CFR § 27.25 - Weight limits.
(a) Maximum weight. The maximum weight (the highest weight at which compliance with each applicable requirement 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 demonstrated if the weights and operating conditions (altitude and temperature) prescribed by those requirements cannot 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 appropriate 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 requested.
(b) Minimum weight. The minimum weight (the lowest weight at which compliance with each applicable requirement 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, assuming for each crewmember a weight no more than 170 pounds, or any lower weight selected by the applicant or included 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 compliance with each applicable flight requirement of this part is shown.
(c) Total weight with jettisonable external load. A total weight for the rotorcraft with a jettisonable external load attached that is greater than the maximum weight established under paragraph (a) of this section may be established for any rotorcraft-load combination if—
(1) The rotorcraft-load combination does not include human external cargo,
(2) Structural component approval for external load operations under either § 27.865 or under equivalent operational 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 weight of all or part of the jettisonable external load,
(4) Structural components of the rotorcraft are shown to comply with the applicable structural requirements of this part under the increased loads and stresses caused by the weight increase over that established under paragraph (a) of this section, and
(5) Operation of the rotorcraft at a total weight greater than the maximum certificated weight established under paragraph (a) of this section is limited by appropriate operating limitations under § 27.865(a) and (d) of this part.