Appendix E to Part 25
14:1.0.1.3.12.11.121.1.11 : Appendix E
Appendix E to Part 25 I - Limited Weight Credit For Airplanes
Equipped With Standby Power
(a) Each applicant for an increase in the maximum certificated
takeoff and landing weights of an airplane equipped with a
type-certificated standby power rocket engine may obtain an
increase as specified in paragraph (b) if -
(1) The installation of the rocket engine has been approved and
it has been established by flight test that the rocket engine and
its controls can be operated safely and reliably at the increase in
maximum weight; and
(2) The Airplane Flight Manual, or the placard, markings or
manuals required in place thereof, set forth in addition to any
other operating limitations the Administrator may require, the
increased weight approved under this regulation and a prohibition
against the operation of the airplane at the approved increased
weight when -
(i) The installed standby power rocket engines have been stored
or installed in excess of the time limit established by the
manufacturer of the rocket engine (usually stenciled on the engine
casing); or
(ii) The rocket engine fuel has been expended or discharged.
(b) The currently approved maximum takeoff and landing weights
at which an airplane is certificated without a standby power rocket
engine installation may be increased by an amount that does not
exceed any of the following:
(1) An amount equal in pounds to 0.014 IN, where I is the
maximum usable impulse in pounds-seconds available from each
standby power rocket engine and N is the number of rocket engines
installed.
(2) An amount equal to 5 percent of the maximum certificated
weight approved in accordance with the applicable airworthiness
regulations without standby power rocket engines installed.
(3) An amount equal to the weight of the rocket engine
installation.
(4) An amount that, together with the currently approved maximum
weight, would equal the maximum structural weight established for
the airplane without standby rocket engines installed.
II - Performance Credit for Transport Category Airplanes Equipped
With Standby Power
The Administrator may grant performance credit for the use of
standby power on transport category airplanes. However, the
performance credit applies only to the maximum certificated takeoff
and landing weights, the takeoff distance, and the takeoff paths,
and may not exceed that found by the Administrator to result in an
overall level of safety in the takeoff, approach, and landing
regimes of flight equivalent to that prescribed in the regulations
under which the airplane was originally certificated without
standby power. For the purposes of this appendix, “standby power”
is power or thrust, or both, obtained from rocket engines for a
relatively short period and actuated only in cases of emergency.
The following provisions apply:
(1) Takeoff; general. The takeoff data prescribed in
paragraphs (2) and (3) of this appendix must be determined at all
weights and altitudes, and at ambient temperatures if applicable,
at which performance credit is to be applied.
(2) Takeoff path.
(a) The one-engine-inoperative takeoff path with standby power
in use must be determined in accordance with the performance
requirements of the applicable airworthiness regulations.
(b) The one-engine-inoperative takeoff path (excluding that part
where the airplane is on or just above the takeoff surface)
determined in accordance with paragraph (a) of this section must
lie above the one-engine-inoperative takeoff path without standby
power at the maximum takeoff weight at which all of the applicable
air-worthiness requirements are met. For the purpose of this
comparison, the flight path is considered to extend to at least a
height of 400 feet above the takeoff surface.
(c) The takeoff path with all engines operating, but without the
use of standby power, must reflect a conservatively greater overall
level of performance than the one-engine-inoperative takeoff path
established in accordance with paragraph (a) of this section. The
margin must be established by the Administrator to insure safe
day-to-day operations, but in no case may it be less than 15
percent. The all-engines-operating takeoff path must be determined
by a procedure consistent with that established in complying with
paragraph (a) of this section.
(d) For reciprocating-engine-powered airplanes, the takeoff path
to be scheduled in the Airplane Flight Manual must represent the
one-engine-operative takeoff path determined in accordance with
paragraph (a) of this section and modified to reflect the procedure
(see paragraph (6)) established by the applicant for flap
retraction and attainment of the en route speed. The scheduled
takeoff path must have a positive slope at all points of the
airborne portion and at no point must it lie above the takeoff path
specified in paragraph (a) of this section.
(3) Takeoff distance. The takeoff distance must be the
horizontal distance along the one-engine-inoperative take off path
determined in accordance with paragraph (2)(a) from the start of
the takeoff to the point where the airplane attains a height of 50
feet above the takeoff surface for reciprocating-engine-powered
airplanes and a height of 35 feet above the takeoff surface for
turbine-powered airplanes.
(4) Maximum certificated takeoff weights. The maximum
certificated takeoff weights must be determined at all altitudes,
and at ambient temperatures, if applicable, at which performance
credit is to be applied and may not exceed the weights established
in compliance with paragraphs (a) and (b) of this section.
(a) The conditions of paragraphs (2)(b) through (d) must be met
at the maximum certificated takeoff weight.
(b) Without the use of standby power, the airplane must meet all
of the en route requirements of the applicable airworthiness
regulations under which the airplane was originally certificated.
In addition, turbine-powered airplanes without the use of standby
power must meet the final takeoff climb requirements prescribed in
the applicable airworthiness regulations.
(5) Maximum certificated landing weights.
(a) The maximum certificated landing weights
(one-engine-inoperative approach and all-engine-operating landing
climb) must be determined at all altitudes, and at ambient
temperatures if applicable, at which performance credit is to be
applied and must not exceed that established in compliance with
paragraph (b) of this section.
(b) The flight path, with the engines operating at the power or
thrust, or both, appropriate to the airplane configuration and with
standby power in use, must lie above the flight path without
standby power in use at the maximum weight at which all of the
applicable airworthiness requirements are met. In addition, the
flight paths must comply with subparagraphs (i) and (ii) of this
paragraph.
(i) The flight paths must be established without changing the
appropriate airplane configuration.
(ii) The flight paths must be carried out for a minimum height
of 400 feet above the point where standby power is actuated.
(6) Airplane configuration, speed, and power and thrust;
general. Any change in the airplane's configuration, speed, and
power or thrust, or both, must be made in accordance with the
procedures established by the applicant for the operation of the
airplane in service and must comply with paragraphs (a) through (c)
of this section. In addition, procedures must be established for
the execution of balked landings and missed approaches.
(a) The Administrator must find that the procedure can be
consistently executed in service by crews of average skill.
(b) The procedure may not involve methods or the use of devices
which have not been proven to be safe and reliable.
(c) Allowances must be made for such time delays in the
execution of the procedures as may be reasonably expected to occur
during service.
(7) Installation and operation; standby power. The
standby power unit and its installation must comply with paragraphs
(a) and (b) of this section.
(a) The standby power unit and its installation must not
adversely affect the safety of the airplane.
(b) The operation of the standby power unit and its control must
have proven to be safe and reliable.
[Amdt. 25-6, 30 FR 8468, July 2, 1965]