681 

Federal Aviation Administration, DOT 

Pt. 29, App. B 

(d) Any oscillation having a period of 20 

seconds or more may not achieve double am-
plitude in less than 20 seconds. 

(e) Any aperiodic response may not achieve 

double amplitude in less than 9 seconds. 

VII. 

Stability Augmentation System (SAS) 

(a) If a SAS is used, the reliability of the 

SAS must be related to the effects of its fail-
ure. Any SAS failure condition that would 
prevent continued safe flight and landing 
must be extremely improbable. It must be 
shown that, for any failure condition of the 
SAS that is not shown to be extremely im-
probable— 

(1) The helicopter is safely controllable 

when the failure or malfunction occurs at 
any speed or altitude within the approved 
IFR operating limitations; and 

(2) The overall flight characteristics of the 

helicopter allow for prolonged instrument 
flight without undue pilot effort. Additional 
unrelated probable failures affecting the con-
trol system must be considered. In addi-
tion— 

(i) The controllability and maneuver-

ability requirements in Subpart B must be 
met throughout a practical flight envelope; 

(ii) The flight control, trim, and dynamic 

stability characteristics must not be im-
paired below a level needed to allow contin-
ued safe flight and landing; 

(iii) For Category A helicopters, the dy-

namic stability requirements of Subpart B 
must also be met throughout a practical 
flight envelope; and 

(iv) The static longitudinal and static di-

rectional stability requirements of Subpart 
B must be met throughout a practical flight 
envelope. 

(b) The SAS must be designed so that it 

cannot create a hazardous deviation in flight 
path or produce hazardous loads on the heli-
copter during normal operation or in the 
event of malfunction or failure, assuming 
corrective action begins within an appro-
priate period of time. Where multiple sys-
tems are installed, subsequent malfunction 
conditions must be considered in sequence 
unless their occurrence is shown to be im-
probable. 

VIII. 

Equipment, systems, and installation. 

The basic equipment and installation must 
comply with Subpart F of Part 29 through 
Amendment 29–14, with the following excep-
tions and additions: 

(a) 

Flight and navigation instruments. 

(1) A 

magnetic gyro-stabilized direction indicator 
instead of the gyroscopic direction indicator 
required by § 29.1303(h); and 

(2) A standby attitude indicator which 

meets the requirements of §§ 29.1303(g)(1) 
through (7), instead of a rate-of-turn indi-
cator required by § 29.1303(g). If standby bat-
teries are provided, they may be charged 
from the aircraft electrical system if ade-
quate isolation is incorporated. The system 

must be designed so that the standby bat-
teries may not be used for engine starting. 

(b) 

Miscellaneous requirements. 

(1) Instru-

ment systems and other systems essential 
for IFR flight that could be adversely af-
fected by icing must be provided with ade-
quate ice protection whether or not the 
rotorcraft is certificated for operation in 
icing conditions. 

(2) There must be means in the generating 

system to automatically de-energize and dis-
connect from the main bus any power source 
developing hazardous overvoltage. 

(3) Each required flight instrument using a 

power supply (electric, vacuum, etc.) must 
have a visual means integral with the instru-
ment to indicate the adequacy of the power 
being supplied. 

(4) When multiple systems performing like 

functions are required, each system must be 
grouped, routed, and spaced so that physical 
separation between systems is provided to 
ensure that a single malfunction will not ad-
versely affect more than one system. 

(5) For systems that operate the required 

flight instruments at each pilot’s station— 

(i) Only the required flight instruments for 

the first pilot may be connected to that op-
erating system; 

(ii) Additional instruments, systems, or 

equipment may not be connected to an oper-
ating system for a second pilot unless provi-
sions are made to ensure the continued nor-
mal functioning of the required instruments 
in the event of any malfunction of the addi-
tional instruments, systems, or equipment 
which is not shown to be extremely improb-
able; 

(iii) The equipment, systems, and installa-

tions must be designed so that one display of 
the information essential to the safety of 
flight which is provided by the instruments 
will remain available to a pilot, without ad-
ditional crew-member action, after any sin-
gle failure or combination of failures that is 
not shown to be extremely improbable; and 

(iv) For single-pilot configurations, instru-

ments which require a static source must be 
provided with a means of selecting an alter-
nate source and that source must be cali-
brated. 

(6) In determining compliance with the re-

quirements of § 29.1351(d)(2), the supply of 
electrical power to all systems necessary for 
flight under IFR must be included in the 
evaluation. 

(c) 

Thunderstorm lights. 

In addition to the 

instrument lights required by § 29.1381(a), 
thunderstorm lights which provide high in-
tensity white flood lighting to the basic 
flight instruments must be provided. The 
thunderstorm lights must be installed to 
meet the requirements of § 29.1381(b). 

IX. 

Rotorcraft Flight Manual. 

A Rotorcraft 

Flight Manual or Rotorcraft Flight Manual 
IFR Supplement must be provided and must 
contain— 

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