AD 80-18-05 ACTIVE

80-18-05 SPERRY FLIGHT SYSTEMS, AVIONICS DIVISION: Amendment 39-3896. Applies to the STARS, (Sperry Three Axis Reference systems), Flight Director Systems installed on aircraft certified in all categories.

Compliance is required as indicated, unless already accomplished.

To prevent possible erroneous presentation of glide slope information, accomplish the following:

(a) Within the next 100 hours' time in service from the effective date of this AD, or within 60 days from the effective date of this AD, whichever occurs sooner, revise the circuit hook-up so that the +28V bias voltage into receptacle J1-b, on the Sperry HSI RD 044 (P/N 2592920-44), RD 444 (P/N 2592920-444) is moved from the +28V dc source, (usually the Flight Director Circuit Breaker), to the +28V dc circuit breaker supplying the glide slope receiver.

NOTE: Sperry Flight Systems Division, Maintenance Manual for STARS Flight Director Instrument System, Pub. No. 15-3321-01 dated 30 November 1969, revised 20 February 1980, shows proper connections.

NOTE: Sperry Flight Systems Technical Newsletter 23-1979-02, Revision 1, dated March 20, 1979, and Revision 2 dated July 11, 1980 refer to this subject. Revision 2 was published to correct typographical error in Revision 1 issue date. The technical content is not changed.

NOTE: Beech Aircraft Corporation letter 900 380-281 dated 19 March 1980 refers to STARS installation in Beech Model 90, 100 and 200 aircraft.

(b) Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base for the accomplishment of modifications required by this AD.

(c) Alternative inspections, modifications or other actions which provide an equivalent level of safety may be used when approved by the Chief, Aircraft Engineering Division, FAA Western Region.

This amendment becomes effective September 29, 1980.