Narrative:

Presented with aircraft X for flight abcd ZZZ to ZZZ1 on tue/aug/06. I was advised by operations that the aircraft had two derivative engines; and at that time there already seemed to be some confusion as to whether this was legally dispatchable. To my knowledge; this was not permitted and I referenced the cfm; page 8-12 revision 7 dated 15/nov/05; to verify this. In the first paragraph under derivative takeoff power; the statement is made that only one engine can be derated. Additionally; on 18-29 systems operations revision 7 dated 15/nov/05; in the section on derivative takeoff power procedures; repeated reference is made to either the derivative engine or the non-derivative engine in the procedures -- however no reference is made to a scenario of two derivative engines. I spoke with dispatch; and was told that dispatch had been told to disregard the cfm as it was wrong regarding this matter; and that there was a memo authorizing this condition for this particular aircraft. I had concerns that accepting the aircraft would be in direct violation of the procedures stated in the cfm; and I contacted the safety hotline; and spoke with mr X who agreed on the position that I should not operate the aircraft in violation of cfm. I later spoke again with dispatch; and they advised me they were connecting me to mr Y and faxing me the memo that authorized the condition. The memo produced was an internal company memo dated 8/aug/06; and stated that both engines on aircraft had X degraded below normal operating range. The action stated was to open a dmi on the engines (which I could not find written up in the dmi log in the aircraft logbook can) and for operations to be conducted in accordance with ge oeb #2. There was a handwritten note on the bottom of the memo saying that the 2 derivative engines are ok; and if dispatch again says 'no; call mr Y.' the signature on handwritten note is illegible. I spoke with mr Y; who said the condition was acceptable; the cfm was inaccurate and that the memo was sufficient authorization. I spoke to mr Z as well; who also concurred with mr Y that the airplane was dispatchable in its current condition. Although I initially had concerns about the contradictions between the manual and the information I was being presented with; after numerous assurances from mr Y and my chief pilot; I accepted release of the aircraft on their good faith; being assured in no uncertain terms that the aircraft was indeed legally dispatchable in its current condition and with the documentation provided. The only other points I can think to bring up regarding this situation are that clarification of the permissibility of two derivative engines should be directly addressed in the cfm; and revision of the current wording of the derivative takeoff power section on cfm 8-12 could prevent further confusion on this subject. Also; verifying that the information regarding derivative engines (be it one or two) is advised to the flight crew operating the aircraft so that they may use the proper preflight performance planning numbers. I asked the advice of at least two capts that had operated the aircraft in question since tue/aug/06; and neither of them stated they saw on the release any remarks regarding any derivative engines; much less two. Also; as I stated earlier; there was no open dmi listed in the dmi log in the aircraft logbook can. The proceeding information is the statement I forwarded to my company via irregularity reports and as soon as possible reporting. However; I want to make absolutely clear on this NASA form (as I did not feel comfortable doing so through company channels) that I was coerced into flying this airplane against the guidance provided me in my company flight manual. I feel my dispatcher was also placed in a difficult situation; as off the record he was not comfortable with this either. My director of operations did not support me in my pilot in command decision to not accept the aircraft; and made me feel that I had no recourse but to do as he ordered.callback conversation with reporter revealed the following information: the reporter stated the maintenance release indicated two engines were derivative (derated power) and checking the crew flight manual it was noted this was not permitted. Only one engine was allowed to be derivative and the flight manual derivative takeoff power had procedures for operating with one engine but not for two engines. The engine performance chart only addresses operation with one derivative engine and the procedure requires setting the non-derivative engine to the maximum torque of the derivative engine without exceeding internal turbine temperature. I contacted two capts that had flown this airplane for advice and was told they were unaware the airplane had derivative engines as it never appeared on the maintenance releases. The reporter stated while the derivative engines appeared on the maintenance release; they were not entered in the deferred maintenance section of the logbook.

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Original NASA ASRS Text

Title: A SF340B WAS DISPATCHED WITH TWO DERIVATIVE; OR DERATED; ENGS NOT PRODUCING THE REQUIRED POWER. DEFERRED IN CONFLICT WITH CREW FLT MANUAL ONLY ONE ENG PERMITTED TO BE DERIVATIVE.

Narrative: PRESENTED WITH ACFT X FOR FLT ABCD ZZZ TO ZZZ1 ON TUE/AUG/06. I WAS ADVISED BY OPS THAT THE ACFT HAD TWO DERIVATIVE ENGS; AND AT THAT TIME THERE ALREADY SEEMED TO BE SOME CONFUSION AS TO WHETHER THIS WAS LEGALLY DISPATCHABLE. TO MY KNOWLEDGE; THIS WAS NOT PERMITTED AND I REFERENCED THE CFM; PAGE 8-12 REVISION 7 DATED 15/NOV/05; TO VERIFY THIS. IN THE FIRST PARAGRAPH UNDER DERIVATIVE TKOF POWER; THE STATEMENT IS MADE THAT ONLY ONE ENG CAN BE DERATED. ADDITIONALLY; ON 18-29 SYSTEMS OPERATIONS REVISION 7 DATED 15/NOV/05; IN THE SECTION ON DERIVATIVE TKOF POWER PROCS; REPEATED REFERENCE IS MADE TO EITHER THE DERIVATIVE ENG OR THE NON-DERIVATIVE ENG IN THE PROCS -- HOWEVER NO REFERENCE IS MADE TO A SCENARIO OF TWO DERIVATIVE ENGS. I SPOKE WITH DISPATCH; AND WAS TOLD THAT DISPATCH HAD BEEN TOLD TO DISREGARD THE CFM AS IT WAS WRONG REGARDING THIS MATTER; AND THAT THERE WAS A MEMO AUTHORIZING THIS CONDITION FOR THIS PARTICULAR ACFT. I HAD CONCERNS THAT ACCEPTING THE ACFT WOULD BE IN DIRECT VIOLATION OF THE PROCS STATED IN THE CFM; AND I CONTACTED THE SAFETY HOTLINE; AND SPOKE WITH MR X WHO AGREED ON THE POSITION THAT I SHOULD NOT OPERATE THE ACFT IN VIOLATION OF CFM. I LATER SPOKE AGAIN WITH DISPATCH; AND THEY ADVISED ME THEY WERE CONNECTING ME TO MR Y AND FAXING ME THE MEMO THAT AUTHORIZED THE CONDITION. THE MEMO PRODUCED WAS AN INTERNAL COMPANY MEMO DATED 8/AUG/06; AND STATED THAT BOTH ENGS ON ACFT HAD X DEGRADED BELOW NORMAL OPERATING RANGE. THE ACTION STATED WAS TO OPEN A DMI ON THE ENGS (WHICH I COULD NOT FIND WRITTEN UP IN THE DMI LOG IN THE ACFT LOGBOOK CAN) AND FOR OPERATIONS TO BE CONDUCTED IN ACCORDANCE WITH GE OEB #2. THERE WAS A HANDWRITTEN NOTE ON THE BOTTOM OF THE MEMO SAYING THAT THE 2 DERIVATIVE ENGS ARE OK; AND IF DISPATCH AGAIN SAYS 'NO; CALL MR Y.' THE SIGNATURE ON HANDWRITTEN NOTE IS ILLEGIBLE. I SPOKE WITH MR Y; WHO SAID THE CONDITION WAS ACCEPTABLE; THE CFM WAS INACCURATE AND THAT THE MEMO WAS SUFFICIENT AUTHORIZATION. I SPOKE TO MR Z AS WELL; WHO ALSO CONCURRED WITH MR Y THAT THE AIRPLANE WAS DISPATCHABLE IN ITS CURRENT CONDITION. ALTHOUGH I INITIALLY HAD CONCERNS ABOUT THE CONTRADICTIONS BETWEEN THE MANUAL AND THE INFO I WAS BEING PRESENTED WITH; AFTER NUMEROUS ASSURANCES FROM MR Y AND MY CHIEF PLT; I ACCEPTED RELEASE OF THE ACFT ON THEIR GOOD FAITH; BEING ASSURED IN NO UNCERTAIN TERMS THAT THE ACFT WAS INDEED LEGALLY DISPATCHABLE IN ITS CURRENT CONDITION AND WITH THE DOCUMENTATION PROVIDED. THE ONLY OTHER POINTS I CAN THINK TO BRING UP REGARDING THIS SITUATION ARE THAT CLARIFICATION OF THE PERMISSIBILITY OF TWO DERIVATIVE ENGS SHOULD BE DIRECTLY ADDRESSED IN THE CFM; AND REVISION OF THE CURRENT WORDING OF THE DERIVATIVE TKOF POWER SECTION ON CFM 8-12 COULD PREVENT FURTHER CONFUSION ON THIS SUBJECT. ALSO; VERIFYING THAT THE INFO REGARDING DERIVATIVE ENGS (BE IT ONE OR TWO) IS ADVISED TO THE FLT CREW OPERATING THE ACFT SO THAT THEY MAY USE THE PROPER PREFLT PERFORMANCE PLANNING NUMBERS. I ASKED THE ADVICE OF AT LEAST TWO CAPTS THAT HAD OPERATED THE ACFT IN QUESTION SINCE TUE/AUG/06; AND NEITHER OF THEM STATED THEY SAW ON THE RELEASE ANY REMARKS REGARDING ANY DERIVATIVE ENGS; MUCH LESS TWO. ALSO; AS I STATED EARLIER; THERE WAS NO OPEN DMI LISTED IN THE DMI LOG IN THE ACFT LOGBOOK CAN. THE PROCEEDING INFO IS THE STATEMENT I FORWARDED TO MY COMPANY VIA IRREGULARITY REPORTS AND ASAP REPORTING. HOWEVER; I WANT TO MAKE ABSOLUTELY CLEAR ON THIS NASA FORM (AS I DID NOT FEEL COMFORTABLE DOING SO THROUGH COMPANY CHANNELS) THAT I WAS COERCED INTO FLYING THIS AIRPLANE AGAINST THE GUIDANCE PROVIDED ME IN MY COMPANY FLT MANUAL. I FEEL MY DISPATCHER WAS ALSO PLACED IN A DIFFICULT SITUATION; AS OFF THE RECORD HE WAS NOT COMFORTABLE WITH THIS EITHER. MY DIRECTOR OF OPERATIONS DID NOT SUPPORT ME IN MY PLT IN COMMAND DECISION TO NOT ACCEPT THE ACFT; AND MADE ME FEEL THAT I HAD NO RECOURSE BUT TO DO AS HE ORDERED.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE MAINT RELEASE INDICATED TWO ENGS WERE DERIVATIVE (DERATED POWER) AND CHKING THE CREW FLT MANUAL IT WAS NOTED THIS WAS NOT PERMITTED. ONLY ONE ENG WAS ALLOWED TO BE DERIVATIVE AND THE FLT MANUAL DERIVATIVE TKOF POWER HAD PROCS FOR OPERATING WITH ONE ENG BUT NOT FOR TWO ENGS. THE ENG PERFORMANCE CHART ONLY ADDRESSES OPERATION WITH ONE DERIVATIVE ENG AND THE PROC REQUIRES SETTING THE NON-DERIVATIVE ENG TO THE MAX TORQUE OF THE DERIVATIVE ENG WITHOUT EXCEEDING INTERNAL TURBINE TEMP. I CONTACTED TWO CAPTS THAT HAD FLOWN THIS AIRPLANE FOR ADVICE AND WAS TOLD THEY WERE UNAWARE THE AIRPLANE HAD DERIVATIVE ENGS AS IT NEVER APPEARED ON THE MAINT RELEASES. THE RPTR STATED WHILE THE DERIVATIVE ENGS APPEARED ON THE MAINT RELEASE; THEY WERE NOT ENTERED IN THE DEFERRED MAINT SECTION OF THE LOGBOOK.

Data retrieved from NASA's ASRS site as of January 2009 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.