B737-700
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 138; Flight Crew Type 11000
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural MEL / CDL; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Weight And Balance
Flight Crew Overcame Equipment Problem
Aircraft; Company Policy; Human Factors; Logbook Entry
Our aircraft had an MEL for the Number One Engine thrust reverser inoperative; which had been previously documented. On the first leg from XXX; the OPC was correctly programmed resulting in a max power takeoff. All ground ops at our next departure airport were normal resulting in a reduced power takeoff on Runway 19L. Upon reaching cruise; something jarred my memory about the requirement to perform a max power takeoff with an inoperative thrust reverser. I then reviewed the OPC again and found out for some reason the MEL button was no longer highlighted. It was my belief that once an MEL had been selected on the OPC that it would be retained for subsequent use. We then began a trial and error with the OPC along with a review of the manual to determine what could have possibly happened. During this exercise; we discovered that during the OPC programming on the ground at our first stop the Onboard Performance System page had been selected when going from landing data to takeoff data versus just selecting the Module menu page. This resulted in the MEL being dropped. Although this was a programming error; I still should have caught the MEL not being highlighted. We talked numerous times on the first leg about the thrust reverser; especially on landing; but for some reason we both completely missed the reduced takeoff commanded by the OPC for our subsequent departure.We get MELs so infrequently; especially ones that require OPC input. My [limited] knowledge on how the OPC retains MELs may have made me a little complacent on what the OPC provides us. We were on top of the MEL the first leg but failed to follow through with the same diligence for the second.
In reviewing how I set up the OPC; it was determined that to return to the main page to enter the second takeoff data; I pressed the stylus button and pressed return. This brought me to the main performance page on the OPC. Unfortunately; this also removes the previously selected MEL from the OPC. I was under impression the OPC retained this information UNTIL deselected as stated in the FRM. The OPC does retain the MEL if you use the Module Menu page; but it does not retain the MEL if you do as I did. We did not notice the MEL had been removed.In reading the MEL; it did not mention that a max power takeoff is required. This is fine considering the OPC; when properly programmed; will calculate the proper takeoff thrust; however; this is the first time I have seen this particular MEL and I was used to seeing restrictions also stated in the paper MEL.
Dispatched with an inoperative left engine reverser the flight crew of a B737-700 computed their takeoff performance utilizing the onboard computer with the relevant MEL item selected and the result required a maximum thrust takeoff due to the MEL. On the next leg the computing process was initiated in a different fashion; the MEL dropped out of memory; and the computer provided takeoff numbers predicated on reduced thrust. The error was not discovered until at cruise on the second leg.