AD 87-06-02

87-06-02 HONEYWELL, INC., SPERRY COMMERCIAL FLIGHT SYSTEMS DIVISION (SPERRY CORPORATION, AEROSPACE AND MARINE GROUP): Amendment 39-5610. Applicable to the following models of Sperry Electronics Flight Instrument Systems (EFIS) Symbol Generators, which have not been modified to Mod Level S or subsequent:

MODEL SPERRY PART NUMBER SG-810 7004544-901 SG-811 7004544-811 SG-610 7004544-902

NOTE: These systems are known to be installed in, but not limited to, deHavilland Model DHC-8, British Aerospace Model BAe 125-800, Cessna Model 650, and Aerospatiale Model ATR-42 series airplanes.

Compliance is required as indicated, unless previously accomplished.

To reduce the possibility of AHRS attitude and heading computations being contaminated, which can result in frozen attitude and heading displays on both instrument panels, accomplish the following:

A. Prior to further flight, install a placard adjacent to the first pilot's electronic attitude direction indicator (EADI), in full view of the pilot, stating "FLIGHT INTO KNOWN IMC PROHIBITED."

B. Modification of the Sperry EFIS Symbol Generator models listed above to Mod Level S or subsequent, or installation of the following Sperry EFIS Symbol Generator models, constitutes terminating action of the operational and placard requirements of paragraph A., above:

MODEL SPERRY PART NUMBERS MOD LEVEL (OR SUBSEQUENT) SG-811 7004544-211 V SG-811 7004544-311 AD SG-811 7004544-411 U SG-611 7004544-611 S

All persons affected by this directive who have not already received the appropriate service documents from the manufacturer, may obtain copies upon request to Honeywell Inc., Sperry Commercial Flight Systems Division (formerly Sperry Corporation, Aerospace and Marine Group), P.O. Box 29000, Phoenix, Arizona 85038-9000. These documents may be examined at the FAA, Northwest Mountain Region, 17900 Pacific Highway South, Seattle, Washington, or the Western Aircraft Certification Office, 15000 Aviation Boulevard, Hawthorne, California.

This Amendment becomes effective May 11, 1987, as to all persons, except those persons to whom it was made immediately effective by Priority Letter AD 87-06-02, issued March 13, 1987.