1AD/INST/37 - Altitude Preselector/Alerter

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 107 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES

Image unavailable in extracted text
Instruments and Automatic Pilots

AD/INST/37 Altitude Preselector/Alerter 5/92

Applicability: Collins PRE-80A and PRE-80B Altitude Preselector/Alerters.

Note: Aircraft that may be fitted with this equipment include, but are not limited to, Falcon 10, 20, 50, 200, SAAB 340, BAe HS 125-700, HS 125-800 and Embraer EMB

Requirement: 1. Modify the Altitude Preselector/Alerter in accordance with Collins PRE-80A/80B Service Bulletin No 6 Revision 3 dated 24 October 1990.

2. Insert the following warning in the Normal Operations Section of the Aircraft Flight Manual until modified in accordance with Requirement 1:

CAUTION AUTOPILOT ALTITUDE CAPTURE

Equipment malfunction may lead to the aircraft failing altitude capture when the flight level set on preselector is reached. Furthermore, exceeding the preselected flight level in this defective manner does not cause a warning, either visual or audio, to be activated.

Therefore, when the aircraft autopilot system is in operation and it is performing transition from one flight level to another, it is essential to monitor preselected altitude capture using the aircraft altimeter.

CAA Approved AD/INST/37 dated 30 April 1992.

Note: DGAC AD 91-076(AB)R1 refers.

Compliance: 1. Prior to further flight after 30 October 1992 for Requirement 1.

2. Prior to further flight after 30 May 1992 for Requirement 2.

Background: Transient or dormant malfunction of the Altitude Preselector/Alerter may allow the Air Data Computer, and consequently the Flight Director/Autopilot Computer, to fly to an altitude other than that shown on the Preselector without presenting either an aural or visual failure annunciation.