A BAE 4100 WAS OPERATED WITH THE FO'S STALL PROTECTION STICK PUSH FUNCTION FORCE LOW AND OUT OF LIMITS.

Date: 1998-04 · Aircraft: Jetstream 41

Anomalies: aircraft-equipment-problem-critical|deviation-discrepancy-procedural-far|deviation-discrepancy-procedural-published-material-policy|other-unspecified

Synopsis

A BAE 4100 WAS OPERATED WITH THE FO'S STALL PROTECTION STICK PUSH FUNCTION FORCE LOW AND OUT OF LIMITS.

Narrative

THE EVENT CAN BEST BE DESCRIBED AS A SYSTEM ABNORMALITY. DURING TAXI-OUT FROM LEX WE PERFORMED MORNING FIRST FLT CHECKS. WHILE COMPLETING THE STALL SYSTEM CHECK; THE FO REPORTED THAT UPON CHECKING THE R STICK SHAKER; THE STICK PUSH FUNCTION ALSO SEEMED TO ACTIVATE BUT NOT WITH FULL PUSHER FORCE. WHEN THE STICK PUSH FUNCTION WAS TESTED A NOTICEABLE DIFFERENCE IN PUSHER FORCE WAS OBSERVED. THE FO AND I AGREED THAT THE SYSTEM OUTPUTS WERE TESTED AND FUNCTIONING. WE DEPARTED AND CONTINUED TO THE DESTINATION (STL) WITHOUT INCIDENT. AFTER ARRIVAL DURING TAXI-IN; WE TESTED THE SYSTEM AGAIN AND FOUND THE SAME RESULT. AFTER SHUTDOWN; MAINT WAS CONSULTED AND THE EVENT RECORDED IN THE ACFT MAINT LOGBOOK. MY CONCERN IN THE MATTER AFTER HAVING APPLIED A GREAT DEAL OF AFTERTHOUGHT IS THAT THIS IRREGULARITY SHOULD HAVE BEEN 'WRITTEN UP' AT THE OUTSTATION AND MAINT ACTION SOUGHT THERE. INSTEAD OF LOOKING AT THE DETAILS FOR FULFILLING TEST REQUIREMENTS (ALLOWING MISSION COMPLETION); THIS EVENT SHOULD HAVE BEEN TAKEN AT FACE VALUE AS AN IRREGULARITY AND THE SYSTEM CONSIDERED PARTIALLY UNAIRWORTHY. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE ACFT WAS A BAE4100 AND THE STALL WARNING AND THE STALL PROTECTION SYS ARE SEPARATE SYS ON THE L AND R CTL COLUMNS. THE RPTR SAID WHEN TEST PRIOR TO TKOF THE FO'S STICK SHAKER OPERATED OK BUT THE STICK PUSH FUNCTION FORCE WAS LOW. THE RPTR SAID IT WAS DECIDED TO GO AS BOTH SYS DID TEST. THE RPTR STATED AFTER A TEST AT TRIP TERMINATION IT WAS CLR THE STICK PUSH FUNCTION WAS NOT NORMAL AND WAS WRITTEN UP FOR MAINT TO CORRECT.

Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.