Narrative:

After a 2 hour and 20 minute maintenance delay had taken place for a previous rejected takeoff (rejected takeoff); another rejected takeoff occurred for the same reason. The auto feather did not arm; the outside temperature was 24 degrees C. After being cleared for takeoff; the brakes were held as the power levers were advanced to 50%; I then released the brakes and applied power to about 90%. The first officer noted that the auto feather did arm and everything was normal except for the takeoff power was now at 92%. He adjusted the power to 90% and the auto feather disengaged. He called 'reject; auto feather not armed' and we rejected takeoff'd with a top speed of 35 KTS. After calling maintenance; we returned to the gate and the flight was canceled. Further discussion with maintenance control revealed there are actually two mods available within the auto feather system. The older mod; that our dhc-8 has installed on it; has a higher power lever angle (pla); than the newer mod with lower temperatures. I read section 9-49 of the pilot's handbook to the supervisor and he insisted that this mod (pre-mod) was different than what we have been informed of in the dhc-8. I feel further clarification between the pilot group and the maintenance department is needed for the 'pre' and 'post' mod auto feather systems after this situation.

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Original NASA ASRS Text

Title: A Captain reports on two Rejected Takeoffs (RTO); he and his First Officer experienced for the same flight in a DHC-8; due to 'Auto feather not armed'. Lack of clarification about the 'Pre' and 'Post' Mod Auto feather system and Power Lever Angle (PLA) differences contributed to problem.

Narrative: After a 2 hour and 20 minute Maintenance delay had taken place for a previous Rejected Takeoff (RTO); another RTO occurred for the same reason. The Auto feather did not arm; the outside temperature was 24 degrees C. After being cleared for takeoff; the brakes were held as the Power Levers were advanced to 50%; I then released the brakes and applied power to about 90%. The First Officer noted that the Auto feather did arm and everything was normal except for the Takeoff Power was now at 92%. He adjusted the power to 90% and the Auto feather disengaged. He called 'REJECT; Auto feather Not Armed' and we RTO'd with a top speed of 35 KTS. After calling Maintenance; we returned to the gate and the Flight was canceled. Further discussion with Maintenance Control revealed there are actually two mods available within the Auto feather System. The older Mod; that our DHC-8 has installed on it; has a higher Power Lever Angle (PLA); than the newer Mod with lower temperatures. I read section 9-49 of the Pilot's Handbook to the Supervisor and he insisted that this Mod (Pre-Mod) was different than what we have been informed of in the DHC-8. I feel further clarification between the Pilot group and the Maintenance department is needed for the 'Pre' and 'Post' Mod Auto feather Systems after this situation.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.