A COMMERCIAL FIXED WING MLG RPTED #1 ENG WENT TO 102 PT 8 PERCENT N1 SPD ON TKOF OUT OF FLT MANUAL LIMITS WHICH ARE IN CONFLICT WITH MAINT MANUAL LIMITS OF 107 PT 7 PERCENT.

Date: 1997-09 · Aircraft: Medium Large Transport; Low Wing; 2 Turbojet Eng · Phase: takeoff

Anomalies: aircraft-equipment-problem-critical|other-unspecified

Synopsis

A COMMERCIAL FIXED WING MLG RPTED #1 ENG WENT TO 102 PT 8 PERCENT N1 SPD ON TKOF OUT OF FLT MANUAL LIMITS WHICH ARE IN CONFLICT WITH MAINT MANUAL LIMITS OF 107 PT 7 PERCENT.

Narrative

DURING TKOF I OBSERVED L ENG INDICATIONS HIGH (N1 ABOVE 100%; EPR RISING ABOVE TKOF SETTING AND TEMPS ABOVE NORMAL) AT THE 80 KT CALL. REDUCED THROTTLE AND RECHKED. ENG INDICATIONS AGAIN TRENDED HIGH. REDUCED THROTTLE TWICE TO TRY TO KEEP ENG INDICATIONS IN LIMITS. DURING CLBOUT I ASKED THE FO WHAT THE L N1 RPM AT MAP WAS. HE SAID HE OBSERVED A MAX OF 102.8%. THE PLTS MANUAL CALLS FOR A MAX OF 100% ON THIS DASH NUMBER ENG (JT8D-9). CONTACTED MAINT. THEY INFORMED ME THAT THE ENG READINGS WERE WITHIN LIMITS. WHEN I ASKED WHY OUR LIMITS WERE LOWER THEY HAD NO RESPONSE. I INFORMED THEM THAT I WOULD CONTINUE TO OUR INTERMEDIATE STOP (AT THIS POINT OF THE FLT WE WERE HALFWAY THERE ANYWAY) BUT WOULD NOT CONTINUE TO THE FINAL DEST WITHOUT PROOF IN WRITING THAT THE LIMITS HAD NOT BEEN EXCEEDED. ON ARR AT THE INTERMEDIATE STOP I WAS INFORMED BY OUR MECH THAT MAINT CTL HAD CALLED AND TOLD HIM THAT THE ENG WAS IN LIMITS AND SENT HIM A FAX SHOWING THE LIMITS AS 107.7. I PHONED MAINT AND DISCUSSED THESE LIMITS AND THE FACT THAT THEY VARIED FROM THE FLC LIMITS -- THEY INSISTED THAT THE FAX SHOWED THE PROPER LIMITS FOR THE -9 ENG; AND THE OUT-BASE MECH SIGNED THE OVERSPD WRITE-UP IN THE LOG AS BEING IN LIMITS. WE FLEW THE ACFT TO OUR FINAL DEST (MAKING A REDUCED PWR TKOF). DURING THE WEEKEND LAYOVER I CALLED MAINT AND FLT STANDARDS TO SEE WHY THERE WAS SUCH A LARGE DIFFERENCE BTWN FLC AND MAINT LIMITS -- I GOT NO ANSWERS. WHEN WE ARRIVED AT THE ACFT; I FOUND THAT MAINT HAD DONE 1 INSPECTION AND RETRIMED THE ENG. WHEN I ASKED WHY THIS WAS DONE IF THE LIMITS HAD NOT BEEN EXCEEDED; I WAS TOLD IT WAS JUST A PRECAUTION. I FILED A DEBRIEF WITH FLT MGMNT AND HAVE NOT RECEIVED AN ANSWER IN OVER A MONTH. I SUSPECT THAT MAINT CTL GAVE ME AND THE OUT-BASED MECH MISLEADING INFO SO THAT WE WOULD CONTINUE THE FLT WITHOUT A MAINT DELAY OR CANCELLATION. IF THIS WASN'T THE CASE THERE CERTAINLY SHOULD NOT BE A DIFFERENCE BTWN THE FLT AND MAINT LIMITS.

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