Narrative:

The first officer seat slid back on takeoff from runway 27 in bos. This occurred at V1 minus 10 KTS. It seems as if the seat locking mechanism was functioning improperly. It was very difficult to get the pins to re-engage after this occurred. Callback conversation with reporter revealed the following information: the reporter stated this is the third incident of the seat releasing when operating the aircraft and all occurred with the first officer the pilot in control. The reporter said the first was at rotation the seat slid back to the stops, second event was during taxi the seat unlocked and moved aft, but did not hit the stops and the third is this incident at V1 speed minus 10 KTS. The reporter stated all of the incidents were logged for maintenance action which is mostly spraying the track and lock pin with lubricant. The reporter said the problem seems to be aggravated by sand and dirt gathering on the floor under the seat and sticking to the lubricant. The reporter stated when first sitting in the seat he will 'rock' the seat and check for locking, but this does not ensure 'positive' locking. The reporter said the carrier issued a flight handbook revision that advises 'to check seat for locking.'

Google
 

Original NASA ASRS Text

Title: AN EMBRAER 135 ON TAKEOFF ROLL WITH FO FLYING AT V1 MINUS 10 KTS SEAT SLID BACK TO STOPS. CAPT SEIZED YOKE TO CONTINUE TAKEOFF. FO EXPERIENCED DIFFICULTY TO REPOSITION AND LOCK SEAT.

Narrative: THE FO SEAT SLID BACK ON TAKEOFF FROM RWY 27 IN BOS. THIS OCCURRED AT V1 MINUS 10 KTS. IT SEEMS AS IF THE SEAT LOCKING MECHANISM WAS FUNCTIONING IMPROPERLY. IT WAS VERY DIFFICULT TO GET THE PINS TO RE-ENGAGE AFTER THIS OCCURRED. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THIS IS THE THIRD INCIDENT OF THE SEAT RELEASING WHEN OPERATING THE ACFT AND ALL OCCURRED WITH THE FO THE PLT IN CONTROL. THE RPTR SAID THE FIRST WAS AT ROTATION THE SEAT SLID BACK TO THE STOPS, SECOND EVENT WAS DURING TAXI THE SEAT UNLOCKED AND MOVED AFT, BUT DID NOT HIT THE STOPS AND THE THIRD IS THIS INCIDENT AT V1 SPEED MINUS 10 KTS. THE RPTR STATED ALL OF THE INCIDENTS WERE LOGGED FOR MAINT ACTION WHICH IS MOSTLY SPRAYING THE TRACK AND LOCK PIN WITH LUBRICANT. THE RPTR SAID THE PROB SEEMS TO BE AGGRAVATED BY SAND AND DIRT GATHERING ON THE FLOOR UNDER THE SEAT AND STICKING TO THE LUBRICANT. THE RPTR STATED WHEN FIRST SITTING IN THE SEAT HE WILL 'ROCK' THE SEAT AND CHK FOR LOCKING, BUT THIS DOES NOT ENSURE 'POSITIVE' LOCKING. THE RPTR SAID THE CARRIER ISSUED A FLT HANDBOOK REVISION THAT ADVISES 'TO CHK SEAT FOR LOCKING.'

Data retrieved from NASA's ASRS site as of July 2007 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.