B757-200
Maintenance Airframe; Maintenance Powerplant
Maintenance Technician 30
Communication Breakdown
Aircraft Equipment Problem Critical
General Flight Cancelled / Delayed; General Maintenance Action
Aircraft; Chart Or Publication; Human Factors
Company B757-200 aircraft. Captain seat track lock assembly faulty. Potential exists for a pilot to loose control and wreck an airplane on approach when the seat shifts unexpectedly. [I am] requesting a directive requiring increased scruntiny of this critical mechanism on B757/B767 fleets. This is an unrecognized safety critical issue. I replaced the seat assembly June 2015. A Routine Inspection Task card for the seat assembly is in use and I suspect this is not enough to prevent future accidents. In this example; the Captain found the problem and made a log entry.
Reporter stated many of the B757s and pilot seats are 25 to 30 years old. He doesn't know when; or if a seat overhaul is required; but he believes the segmented checks on their B757s only require a yearly inspection for seat operation and condition. He found both tension springs broken under the Captain's seat for the Track Lock Control lever. The lock lever overcomes the spring tension in order to release the pin that locks the seat in the seat tracks. The springs were not a line replaceable item. With both springs broken; the Track Lock Control lever did not have a positive tension to secure the seat's latching pin in the seat's floor tracks. As a result; he could easily make the seat slide forward or aft merely by shifting his weight in the seat.Reporter believes the minimal maintenance checks for flight crew seats are not adequate to maintain seat serviceability. That's why reporter was requesting a fleet wide campaign to check flight crew seats on B757/B767s. Reporter wants to be clear that the seat design is not the issue; just the limited maintenance checks of the seats; which do not seem to be adequate.
A Line Aircraft Maintenance Technician (AMT) reports about an unrecognized critical safety issue that exists for pilots to lose control of B757/B767 aircraft on approach; if the pilot seat shifts unexpectedly due to broken Seat Track Lock Control assemblies. Technician suspects the routine seat inspection task card is not sufficient to maintain adequate serviceability of crew seats.