Summary
This document proposes to revise an earlier proposed airworthiness directive (AD) that would have required removing the ground inhibit time delay and the ground test relay from the stall warning and protection system on certain British Aerospace Jetstream Models 3101 and 3201 airplanes that are equipped with the ground inhibit function (Modification JM7813A (SB 27-JM7813A) or JM7813B). This proposed AD would have also required rewiring part of the stall warning and protection system to assure that system reliance is maintained after relay removal. The proposed AD was the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for the United Kingdom. Since issuing the NPRM, British Aerospace has revised the service information referenced in the previous proposal to correct a certain portion of the procedures. The Federal Aviation Administration (FAA) has determined that these corrected procedures in the revised service information should be incorporated into the NPRM, and that the comment period for the proposal should be reopened and the public should have additional time to comment. The actions specified by the proposed AD are intended to prevent failure of the ground inhibit relay while it is in the energized position caused by the current design, which could result in failure of the stall warning system and possible loss of control of the airplane in certain situations if the crew was not aware that the system had failed.