AD 93-07-10

93-07-10 MCDONNELL DOUGLAS HELICOPTER COMPANY AND HUGHES HELICOPTERS, INC.: Amendment 39-8542. Docket Number 92-ASW-42.

Applicability: Model 369D, 369E, 369F, 369HE and 369HS series helicopters, equipped with Gajon Associates, LTD. (Viking Helicopters Limited) Supplemental Type Certificate (STC) No. SH1134EA external cargo container kit (baggage pod), with or without the auxiliary fuel system, certificated in any category.

Compliance: Required within 10 days or 25 hours' time-in-service, whichever occurs first, after the effective date of this AD, unless accomplished previously.

To prevent hazardous yaw oscillations during descents, which could result in loss of control of the helicopter, accomplish the following:

(a) Install a durable placard on the instrument panel as close as is practical to the airspeed indicator and that is legible to the pilot that reads:

BAGGAGE POD INSTALLED Vne-90 KIAS IN POWERED DESCENT (>1000 fpm) OR IN AUTOROTATION(b) Insert the following statement into the Operating Limitations Section of the flight manual supplement for the baggage pod:

AIRSPEED LIMITS Vne is 90 KIAS in moderate rates of powered descent (greater than 1,000 fpm) or in autorotation with baggage pod installed.

(c) Insert the following statement into the Emergency and Malfunction Procedures Section of the flight manual supplement for the baggage pod:

ENGINE FAILURE AT HIGH CRUISE SPEED

NOTE: At speeds in excess of 90 KIAS in stabilized moderate descents (greater than 1,000 fpm) or in autorotation, the lateral directional handling of the helicopter is degraded. Yaw oscillation may occur and persist, and there is a tendency for the pilot to overcontrol.

(1) Adjust collective pitch according to altitude and airspeed to maintain rotor speed between 410 and 508 RPM.

(2) Apply pedal pressure as necessary to control aircraft yaw.

(3) Adjust cyclic control as necessary to reduce airspeed to90 KIAS or less as collective is lowered and stabilized autorotation is achieved.

NOTE: See basic rotorcraft flight manual for recommended minimum rate of descent and maximum glide distance power-off speeds.

(d) Compliance with Paragraphs (b) and (c) above may be accomplished by attaching a copy of the appropriate AD paragraphs to the Operating Limitations Section and Emergency Procedure Section of the flight manual supplement.

(e) An alternative method of compliance or adjustment of the compliance time, which provides an acceptable level of safety, may be used when approved by the Manager, New York Aircraft Certification Office, FAA, 181 South Franklin Avenue, room 202, Valley Stream, New York. Operators shall submit their requests through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, New York Aircraft Certification Office.

NOTE: Information concerning the existence of approved alternative methods of compliancewith this AD, if any, may be obtained from the Manager, New York Aircraft Certification Office.

(f) Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate the helicopter to a location where the requirements of this AD can be accomplished.

(g) This amendment becomes effective on July 6, 1993.