Narrative:

We did a reduced 22K power takeoff and as the PNF; I noticed a significant difference in our egt's and ff's for both engines. Considering it was only 14 degrees C outside; I thought the #2 engine egt was abnormally high (891 degrees C) versus 788 degrees C for the #1 engine. I also noticed an approximately 800 pounds per hour split in the fuel flow with #2 being the higher. All other indications were normal. I made a comment and showed the captain climbing out of 400 ft that it seemed awfully high for the conditions and the takeoff in las would be interesting. While en route; we discussed the large difference as well as started pre-calculating our maximum weights for different runway and bleed combinations in anticipation of the hot WX and heavy passenger load out of las. Upon arrival in las; the captain and I both went to operations and he immediately called maintenance control and told them all of the above. He also relayed very clearly our deep concern that not only was the engine very weak out on a reduced power cool ambient temperature takeoff; but we needed maximum engine performance out of las due to our maximum weight dispatch and the very real possibility; based on a very suspect weak engine; that we would be doing a high speed abort in very hot high density altitude conditions while doing an improved climb takeoff procedure using very high takeoff v-spds. He told us that we would need to just go ahead and 'give it a try' and see what happened. After more prompting by the captain that we may not make full power and would have to reduce the engine to avoid exceeding the fhb stated maximum egt of 930; he said 'it's ok to exceed the limits a little bit.' he said certain 'minor exceedances' are acceptable. The captain asked what he considered 'minor.' the maintenance controller guy said up to 960. He then said to go ahead and go and if it exceeds the limits to go ahead and note the time and temperature and write it up at destination and they would take care of it there. He then looked up history and found something saying that the trend monitoring department had flagged something with the #2 egt gauge as possibly having an indication problem. There was no known error that we knew of or had knowledge of. I also made the comment to the captain that we had a huge ff split too; not just the egt difference. The other concern we had was if the gauge was bad; how do we know if we are making power during a maximum performance required takeoff. Answer is; we don't. The maintenance guy said he would check on more data as the trend monitoring guy who sent out the notice would be back in the office 'in a couple mins.' the captain then had us xferred to dispatch and informed him of the problem. All the above conversation was done on speaker phone so the operations agent and I heard all this. We went back to the airplane to await the news. We got an ACARS from dispatch asking if we had any relief or help from maintenance control to which I responded 'no.' we got another ACARS from dispatch asking us if we wanted to decrease takeoff weight or go with release weight; to which we had no answer because at this point due to the ambient conditions; it was a problem with the engine just making power. The customer service agent came down around this time and took it upon herself to start soliciting volunteers (we were completely boarded) to get off; if we needed to reduce weight. The next thing we heard was we got an ACARS message from dispatch saying that we would be hearing from a 'maintenance controller' soon. We were contacted shortly thereafter by the maintenance controller and were told that based on their information; we should go and if it exceeded the limits to go and write it up and they'd take care of it at destination. The captain then went inside to call the flight office and I began trying to contact someone in union safety for guidance. I went inside shortly after the captain did and found him on the phone. The captain also said that if we were being forced to go; we needed someone with a name we knew to sign a document directing us to depart with the conditions we had and were concerned about and to exceed the limitations. I did not hear the comments; but the captain relayed after he hung up with him that he was going to look into it andcall us back. When they called back; maintenance control tells us that our #1 engine has a modification on it that the line pilots have not been informed of. That is some sort of efficiency unit called a 3-D aeronautical compressor modification that runs that engine about 40-60 degrees cooler than one without one. This would explain our difference somewhat but still not the 100 degrees difference we observed on takeoff; but it was more acceptable to us than to be told to 'go ahead and depart and exceed the limitation to get in the air.' I did hear the captain ask very clearly that if we go we very likely could face a hot; high speed abort and that we would not in any way exceed any limitations. He acknowledged that and said it's ok to go. We discussed it and decided based on the new information on this secret modification; we would go try it. Before we pushed; I queried ground as to actual current temperature and winds (37.8 degrees and calm) and recomputed the numbers for runway 1L (runway 1R was closed) and asked ground if it was available and he said yes with about a 30 min delay. We called dispatch direct and notified him of the conditions and that we would try runway 1L. He agreed that was our only chance based on load and temperature and said he would call tower and see if we could get some help on the delay before it got hotter. We ran our checklists and pushed back. While we were taxiing out (had a delay because we were going opposite direction with one taxiway because taxiway B was closed in our ramp area) a new ATIS came out stating the temperature was now 39 degrees. This put our maximum weight at 124.2 by my math. We discussed this as we pushed back and were released at 125.0 and were now overweight. We sent an ACARS to dispatch back and were released at 125.0 and were now overweight. We sent an ACARS to dispatch asking to delete the altitude to drop our minimum fuel by 900 pounds to get us to 124.1. After some discussion via operations; we received an amended release changing our minimum fuel to 16.2; deleting our altitude and our takeoff weight to 124.1. Due to our excessive taxi time; we indeed had burned off all the fuel and were once again legal. We finally got airborne shortly after. Supplemental information from acn 699178: the initial recommendation by maintenance control of this situation raises serious concern. To be told to go ahead and knowingly violate a limitation; if it happened; is clearly not allowed by the fom; flight handbook or condoned by our training. The decision of the company to send the B737-400 into las in the summer expecting it to carry high passenger loads is an operationally poor and possibly dangerous decision. The absolute absence of any information to the flight crew concerning the modified engine indications is unacceptable. The fact that maintenance had the #2 engine egt indicating system 'on watch' with no information to the flight crew is unacceptable.

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Original NASA ASRS Text

Title: B737-400 FLT CREW HAS HIGH EGT ON #2 ENG AND IS CONCERNED WITH A HOT AND HIGH TKOF FROM LAS.

Narrative: WE DID A REDUCED 22K PWR TKOF AND AS THE PNF; I NOTICED A SIGNIFICANT DIFFERENCE IN OUR EGT'S AND FF'S FOR BOTH ENGS. CONSIDERING IT WAS ONLY 14 DEGS C OUTSIDE; I THOUGHT THE #2 ENG EGT WAS ABNORMALLY HIGH (891 DEGS C) VERSUS 788 DEGS C FOR THE #1 ENG. I ALSO NOTICED AN APPROX 800 LBS PER HR SPLIT IN THE FUEL FLOW WITH #2 BEING THE HIGHER. ALL OTHER INDICATIONS WERE NORMAL. I MADE A COMMENT AND SHOWED THE CAPT CLBING OUT OF 400 FT THAT IT SEEMED AWFULLY HIGH FOR THE CONDITIONS AND THE TKOF IN LAS WOULD BE INTERESTING. WHILE ENRTE; WE DISCUSSED THE LARGE DIFFERENCE AS WELL AS STARTED PRE-CALCULATING OUR MAX WTS FOR DIFFERENT RWY AND BLEED COMBINATIONS IN ANTICIPATION OF THE HOT WX AND HVY PAX LOAD OUT OF LAS. UPON ARR IN LAS; THE CAPT AND I BOTH WENT TO OPS AND HE IMMEDIATELY CALLED MAINT CTL AND TOLD THEM ALL OF THE ABOVE. HE ALSO RELAYED VERY CLRLY OUR DEEP CONCERN THAT NOT ONLY WAS THE ENG VERY WEAK OUT ON A REDUCED PWR COOL AMBIENT TEMP TKOF; BUT WE NEEDED MAX ENG PERFORMANCE OUT OF LAS DUE TO OUR MAX WT DISPATCH AND THE VERY REAL POSSIBILITY; BASED ON A VERY SUSPECT WEAK ENG; THAT WE WOULD BE DOING A HIGH SPD ABORT IN VERY HOT HIGH DENSITY ALT CONDITIONS WHILE DOING AN IMPROVED CLB TKOF PROC USING VERY HIGH TKOF V-SPDS. HE TOLD US THAT WE WOULD NEED TO JUST GO AHEAD AND 'GIVE IT A TRY' AND SEE WHAT HAPPENED. AFTER MORE PROMPTING BY THE CAPT THAT WE MAY NOT MAKE FULL PWR AND WOULD HAVE TO REDUCE THE ENG TO AVOID EXCEEDING THE FHB STATED MAX EGT OF 930; HE SAID 'IT'S OK TO EXCEED THE LIMITS A LITTLE BIT.' HE SAID CERTAIN 'MINOR EXCEEDANCES' ARE ACCEPTABLE. THE CAPT ASKED WHAT HE CONSIDERED 'MINOR.' THE MAINT CTLR GUY SAID UP TO 960. HE THEN SAID TO GO AHEAD AND GO AND IF IT EXCEEDS THE LIMITS TO GO AHEAD AND NOTE THE TIME AND TEMP AND WRITE IT UP AT DEST AND THEY WOULD TAKE CARE OF IT THERE. HE THEN LOOKED UP HISTORY AND FOUND SOMETHING SAYING THAT THE TREND MONITORING DEPT HAD FLAGGED SOMETHING WITH THE #2 EGT GAUGE AS POSSIBLY HAVING AN INDICATION PROB. THERE WAS NO KNOWN ERROR THAT WE KNEW OF OR HAD KNOWLEDGE OF. I ALSO MADE THE COMMENT TO THE CAPT THAT WE HAD A HUGE FF SPLIT TOO; NOT JUST THE EGT DIFFERENCE. THE OTHER CONCERN WE HAD WAS IF THE GAUGE WAS BAD; HOW DO WE KNOW IF WE ARE MAKING PWR DURING A MAX PERFORMANCE REQUIRED TKOF. ANSWER IS; WE DON'T. THE MAINT GUY SAID HE WOULD CHK ON MORE DATA AS THE TREND MONITORING GUY WHO SENT OUT THE NOTICE WOULD BE BACK IN THE OFFICE 'IN A COUPLE MINS.' THE CAPT THEN HAD US XFERRED TO DISPATCH AND INFORMED HIM OF THE PROB. ALL THE ABOVE CONVERSATION WAS DONE ON SPEAKER PHONE SO THE OPS AGENT AND I HEARD ALL THIS. WE WENT BACK TO THE AIRPLANE TO AWAIT THE NEWS. WE GOT AN ACARS FROM DISPATCH ASKING IF WE HAD ANY RELIEF OR HELP FROM MAINT CTL TO WHICH I RESPONDED 'NO.' WE GOT ANOTHER ACARS FROM DISPATCH ASKING US IF WE WANTED TO DECREASE TKOF WT OR GO WITH RELEASE WT; TO WHICH WE HAD NO ANSWER BECAUSE AT THIS POINT DUE TO THE AMBIENT CONDITIONS; IT WAS A PROB WITH THE ENG JUST MAKING PWR. THE CUSTOMER SVC AGENT CAME DOWN AROUND THIS TIME AND TOOK IT UPON HERSELF TO START SOLICITING VOLUNTEERS (WE WERE COMPLETELY BOARDED) TO GET OFF; IF WE NEEDED TO REDUCE WT. THE NEXT THING WE HEARD WAS WE GOT AN ACARS MESSAGE FROM DISPATCH SAYING THAT WE WOULD BE HEARING FROM A 'MAINT CTLR' SOON. WE WERE CONTACTED SHORTLY THEREAFTER BY THE MAINT CTLR AND WERE TOLD THAT BASED ON THEIR INFO; WE SHOULD GO AND IF IT EXCEEDED THE LIMITS TO GO AND WRITE IT UP AND THEY'D TAKE CARE OF IT AT DEST. THE CAPT THEN WENT INSIDE TO CALL THE FLT OFFICE AND I BEGAN TRYING TO CONTACT SOMEONE IN UNION SAFETY FOR GUIDANCE. I WENT INSIDE SHORTLY AFTER THE CAPT DID AND FOUND HIM ON THE PHONE. THE CAPT ALSO SAID THAT IF WE WERE BEING FORCED TO GO; WE NEEDED SOMEONE WITH A NAME WE KNEW TO SIGN A DOCUMENT DIRECTING US TO DEPART WITH THE CONDITIONS WE HAD AND WERE CONCERNED ABOUT AND TO EXCEED THE LIMITATIONS. I DID NOT HEAR THE COMMENTS; BUT THE CAPT RELAYED AFTER HE HUNG UP WITH HIM THAT HE WAS GOING TO LOOK INTO IT ANDCALL US BACK. WHEN THEY CALLED BACK; MAINT CTL TELLS US THAT OUR #1 ENG HAS A MODIFICATION ON IT THAT THE LINE PLTS HAVE NOT BEEN INFORMED OF. THAT IS SOME SORT OF EFFICIENCY UNIT CALLED A 3-D AERO COMPRESSOR MODIFICATION THAT RUNS THAT ENG ABOUT 40-60 DEGS COOLER THAN ONE WITHOUT ONE. THIS WOULD EXPLAIN OUR DIFFERENCE SOMEWHAT BUT STILL NOT THE 100 DEGS DIFFERENCE WE OBSERVED ON TKOF; BUT IT WAS MORE ACCEPTABLE TO US THAN TO BE TOLD TO 'GO AHEAD AND DEPART AND EXCEED THE LIMITATION TO GET IN THE AIR.' I DID HEAR THE CAPT ASK VERY CLRLY THAT IF WE GO WE VERY LIKELY COULD FACE A HOT; HIGH SPD ABORT AND THAT WE WOULD NOT IN ANY WAY EXCEED ANY LIMITATIONS. HE ACKNOWLEDGED THAT AND SAID IT'S OK TO GO. WE DISCUSSED IT AND DECIDED BASED ON THE NEW INFO ON THIS SECRET MODIFICATION; WE WOULD GO TRY IT. BEFORE WE PUSHED; I QUERIED GND AS TO ACTUAL CURRENT TEMP AND WINDS (37.8 DEGS AND CALM) AND RECOMPUTED THE NUMBERS FOR RWY 1L (RWY 1R WAS CLOSED) AND ASKED GND IF IT WAS AVAILABLE AND HE SAID YES WITH ABOUT A 30 MIN DELAY. WE CALLED DISPATCH DIRECT AND NOTIFIED HIM OF THE CONDITIONS AND THAT WE WOULD TRY RWY 1L. HE AGREED THAT WAS OUR ONLY CHANCE BASED ON LOAD AND TEMP AND SAID HE WOULD CALL TWR AND SEE IF WE COULD GET SOME HELP ON THE DELAY BEFORE IT GOT HOTTER. WE RAN OUR CHKLISTS AND PUSHED BACK. WHILE WE WERE TAXIING OUT (HAD A DELAY BECAUSE WE WERE GOING OPPOSITE DIRECTION WITH ONE TXWY BECAUSE TXWY B WAS CLOSED IN OUR RAMP AREA) A NEW ATIS CAME OUT STATING THE TEMP WAS NOW 39 DEGS. THIS PUT OUR MAX WT AT 124.2 BY MY MATH. WE DISCUSSED THIS AS WE PUSHED BACK AND WERE RELEASED AT 125.0 AND WERE NOW OVERWT. WE SENT AN ACARS TO DISPATCH BACK AND WERE RELEASED AT 125.0 AND WERE NOW OVERWT. WE SENT AN ACARS TO DISPATCH ASKING TO DELETE THE ALT TO DROP OUR MINIMUM FUEL BY 900 LBS TO GET US TO 124.1. AFTER SOME DISCUSSION VIA OPS; WE RECEIVED AN AMENDED RELEASE CHANGING OUR MINIMUM FUEL TO 16.2; DELETING OUR ALT AND OUR TKOF WT TO 124.1. DUE TO OUR EXCESSIVE TAXI TIME; WE INDEED HAD BURNED OFF ALL THE FUEL AND WERE ONCE AGAIN LEGAL. WE FINALLY GOT AIRBORNE SHORTLY AFTER. SUPPLEMENTAL INFO FROM ACN 699178: THE INITIAL RECOMMENDATION BY MAINT CTL OF THIS SITUATION RAISES SERIOUS CONCERN. TO BE TOLD TO GO AHEAD AND KNOWINGLY VIOLATE A LIMITATION; IF IT HAPPENED; IS CLRLY NOT ALLOWED BY THE FOM; FLT HANDBOOK OR CONDONED BY OUR TRAINING. THE DECISION OF THE COMPANY TO SEND THE B737-400 INTO LAS IN THE SUMMER EXPECTING IT TO CARRY HIGH PAX LOADS IS AN OPERATIONALLY POOR AND POSSIBLY DANGEROUS DECISION. THE ABSOLUTE ABSENCE OF ANY INFO TO THE FLT CREW CONCERNING THE MODIFIED ENG INDICATIONS IS UNACCEPTABLE. THE FACT THAT MAINT HAD THE #2 ENG EGT INDICATING SYS 'ON WATCH' WITH NO INFO TO THE FLT CREW IS UNACCEPTABLE.

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.