AD 86-14-51 R1 ACTIVE

86-14-51 R1 THE DeHAVILLAND AIRCRAFT COMPANY OF CANADA, A DIVISION OF BOEING OF CANADA, LTD.: Amendment 39-5423 as amended by Amendment 39-5969. Applies to Model DHC-8-101 series airplanes, Serial Number 003 and subsequent, certificated in any category.

Compliance is required as indicated, unless previously accomplished.

To preclude the uncommanded deployment of ground spoilers and roll control spoilers in the ground mode, accomplish the following:

A. Prior to further flight, lockout circuit breaker ROLL SPLRS CONT, location F6, right essential bus, and circuit breaker GND SPLRS CONT, location C7, left main bus, in accordance with Section A of de Havilland Alert Service Bulletin AB-27-25, dated July 3, 1986. Install a placard in the flight compartment, on the glareshield under the flight/taxi switch, to state the following: "GROUND SPOILERS AND ROLL CONTROL SPOILERS IN GROUND MODE ARE INOPERATIVE."

B. Prior to further flight, insert a copy of this AD in the Airplane Flight Manual (AFM) Limitations Section. The elimination of all spoiler functions in ground mode increases landing distance and landing field length required by 15 percent when using flaps at 35 degrees (AFM, Figure 5.8.4.), and 10 percent when using flaps at 15 degrees (AFM Supplement No. 9, Figure 5.8.7.). With all spoiler functions in ground mode inoperative, there is negligible increase in the takeoff distance required and the takeoff run required.

C. Within 6 months after the effective date of this amendment, re-establish normal use of all spoilers in the ground mode configuration and remove the operating limitations of paragraphs A. and B., above, by accomplishing the following:

1. Modify the Landing Gear Proximity Switch Electronic Unit (PSEU) in accordance with de Havilland Service Bulletin 8-32-54, Revision B, dated November 20, 1987.

2. Modify the electrical power phase supply for the PSEU BITE Power Circuit, in accordance with de Havilland Service Bulletin 8-32-55, Revision A, dated November 20, 1987.

3. Remove the placard required by paragraph A., above, and reinstate the equipment required to be deactivated by paragraphs A. and B., above, in accordance with the instructions of de Havilland Service Bulletin 8-27-34, Revision C, dated January 8, 1988.

D. An alternate means 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, New England Region.

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

This amendment, 39-5969, amends AD 86-14-51, Amendment 39-5423 effective October 6, 1986, as to all persons except those to whom it was made immediately effective by telegraphic AD T86-14-51 issued July 8, 1986.

This amendment, 39-5969, becomes effective August 11, 1988.