AD 86-16-51 ACTIVE

86-16-51 DEHAVILLAND: Amendment 39-5433. Applies to DeHavilland Model DHC-8 airplanes, certificated in any category, serial numbers 003, 005, and subsequent. Compliance is required before further flight, unless previously accomplished.

To preclude the uncommanded retraction of the main landing gear, accomplish the following:

A. Insert a copy of this AD in the Airplane Flight Manual (AFM) and advise all flight crew members. For takeoff, landing, and while on the ground, isolate the main landing gear actuation hydraulics by complying with the following revised flight manual procedures:

OPERATING LIMITATIONS

(A) Nosewheel steering switch must be selected OFF.

(B) Takeoff or landing in cross winds exceeding 20 knots is not permitted.

NOTE: Information presented in Supplement 12 of the Airplane Flight Manual (Operation with Inoperative Nose Wheel Steering) is in error and will be amended in the next AFM revision.

2. NORMAL OPERATING PROCEDURES:- Flight Compartment Check - POWER ON.

- (ADD) Landing Gear Selector Lever - DOWN. Check 3 green lights ON. All door and gear unlocked lights OUT. Selector lever light OUT.

- Landing Gear Inhibit Switch - INHIBIT.

- Landing Gear Alternate Release Door - OPEN FULLY.

- Landing Gear Alternate Extension Door - OPEN FULLY.

- Hydraulic Pump Handle - INSERT IN HAND PUMP SOCKET AND OPERATE UNTIL HAND PUMP MOVEMENT BECOMES STIFF.

- Hydraulic Pump Handle - STOW.

Pre-Taxi Checks:

11. (CHANGE) Nosewheel Steering Switch - OFF. Steer the airplane on the ground by means of differential braking and power lever adjustment.

After Takeoff:

1. (CHANGE) Upon Achieving Positive Rate of Climb:

- Landing Gear Alternate Release and Landing Gear Alternate Extension Doors - CLOSE FULLY.
- Landing Gear Inhibit Switch - NORM.

- Landing Gear Selector Lever - UP. Check all gear and door lights and gear selector lever light OUT.

NOTE: Should landing gear selector lever be selected UP prior to closing Landing Gear Alternate Release and Landing Gear Alternate Extension Doors and prior to selecting Landing Gear Inhibit Switch to NORMAL, reselect Landing Gear Selector Lever DOWN and accomplish gear retraction as per revised procedure.

NOTE: Landing Gear Alternate Release and Landing Gear Alternate Extension Doors and Landing Gear Inhibit Switch are not within reach of captain when secured in left-hand seat in normal flying position.

Approach:

1. (CHANGE) Landing Gear Selector Lever - DOWN.

- Check 3 green lights ON.

- All door and gear unlocked lights OUT.

- Selector lever light OUT.

- Landing Gear Inhibit Switch - INHIBIT.

- Landing Gear Alternate Release Door - OPEN FULLY.

- Landing Gear Alternate Extension Door - OPEN FULLY.

- Hydraulic Pump Handle - INSERT IN HAND PUMP SOCKET AND OPERATE UNTIL HAND PUMP MOVEMENT BECOMES STIFF.

- Hydraulic Pump Handle - STOW.

- (ADD) Nosewheel Steering Switch - OFF.

Go-around from final approach:

5. (CHANGE) Upon achieving positive rate of climb:

- Landing Gear Alternate Release and Landing Gear Alternate Extension Doors - CLOSE FULLY.

- Landing Gear Inhibit Switch - NORMAL.

- Landing Gear Selector Lever - UP. Check all gear and door lights and gear selector lever light OUT.

3. EMERGENCY OPERATING PROCEDURES:

Engine Failure or Fire After V1:

2. (CHANGE) Gear retraction procedures as above for go- around from final approach.

One Engine Inoperative Approach and Landing:

1. (CHANGE) Landing Gear:

If No. 1 Engine Inoperative:

- Gear extension procedure as above for approach.

If No. 2 Engine Inoperative:

- Airspeed - 140 KT IAS MAXIMUM.

- Landing Gear Inhibit Switch - INHIBIT.

- Landing Gear Selector Lever - DOWN.

- Landing Gear Alternate Release Door - OPEN FULLY.

- Main Landing Gear Release Handle - PULL FULLY DOWN.

- Landing Gear Alternate Extension Door - OPEN FULLY. Insert pump handle in hand pump socket and operate until main landing gear locks down (left and right green lights ON, and left door and right door amber lights ON) and handpump movement becomes stiff.

- Nose Gear Alternate Release Handle - PULL FULLY UP. Check nose green light and nose door amber light on. If any of the gear locked down (green) lights fail to illuminate:

- Gear Locked Down Indicator Light Switch - ON. Check for illumination of appropriate gear down lock alternate light.

- Anti-skid Switch - TEST.

- PTU Manual Switch - PTU MANUAL.

One Engine Inoperative Approach Climb (Overshoot):

3. (CHANGE) Gear retraction procedure as above for go- around from final approach.

4. PERFORMANCE DATA:

(A) Takeoff Distance Required - INCREASE BY TWO PERCENT.

(B) Takeoff Run Required - INCREASE BY TWO PERCENT.

(C) Accelerate-Stop Distance Required - INCREASE BY TWO PERCENT.

B. No later than November 1, 1986, incorporate DHC Modification 8/0567 in accordance with DHC Service Bulletin 8-32-35, dated July 31, 1986. Remove the copy of this directive from the AFM.

C. Alternate means of compliance which provide an acceptable level of safety may be used when approved by the Manager, New York Aircraft Certification Office, FAA, New England Region.

All persons affected by this directive who have not already received the appropriate service documents from the manufacturer, may obtain copies upon request to DeHavilland Aircraft of Canada, Ltd., Garrett Boulevard, Downsview, Ontario M3K 1Y5, Canada. These documents may be examined at the FAA, Northwest Mountain Region, 17900 Pacific Highway South, Seattle, Washington, or FAA, New England Region, New York Aircraft Certification Office, 181 South Franklin Avenue, Room 202, Valley Stream, New York.

This airworthiness directive becomes effective October 20, 1986, as to all persons except those persons to whom it was made immediately effective by telegraphic AD T86-16-51, issued August 15, 1986.