Narrative:

Aircraft was operating under MEL xa 'leading edge flap/slat system' and was an originator. My assigned captain had been rerted, and a new captain was en route, deadheading. I noted the logbook MEL write-up and briefly reviewed the MEL description provided by the operations agent. The MEL was 3 pages long, and I did not take the time to thoroughly read it, as I had preflight duties to accomplish and assumed the captain would review it and decide what actions, if any, were required. Captain arrived late. Reviewed the logbook and MEL, and completed his checks. When done, he described the procedure for handling the MEL'ed flap/slat system: with the 'stall warning asymmetry mode' circuit breakers collared, we could proceed normally if the forward panel 'leading edge flaps transit' lights and overhead leading edge device annunciator panel lights extinguished prior to departure. As I recall, I concurred with this conclusion, and we both noted the lights indicated normal sometime between the after start and the pre start checklists at las. The captain agreed with my conclusions regarding FL230. It was after the sequence was completed at ZZZ that the captain called to inform me of our error. (He and the oncoming captain discussed it during my captain's deadheading flight home). In fact, the MEL requires that if both the forward panel and annunciator lights are 'inoperative' (and placarded) that speed/altitude restrs apply regardless of light status. I erred in not taking the time to read the MEL and determine which scenario of the several listed applied to our aircraft. The next day, I noted the key words 'or' and 'and, in addition' (referring to forward panel and overhead annunciator lights) are all that modify otherwise identical language in the descriptive sentences of the several sections of this MEL. I recall reading over the first section, missing the word 'or' and assuming it applied to us. When the captain announced that was the course of action we would take (he came to the same conclusion I did), the hook was set. In the future, I will thoroughly review each MEL and logbook entry (whether I am the PIC or not), and discuss it with the other pilot to be sure both of us completely understand and agree on the required course of action. This MEL was particularly difficult to read and understand, and I believe that contributed to our error. If there were some way to highlight or point out exactly which area of an MEL applied to an aircraft (ie, a speed/altitude restr), it would vastly reduce the odds of a flight crew taking the wrong course of action.

Google
 

Original NASA ASRS Text

Title: B737-300 CREW DID NOT OBSERVE MEL RESTRS LISTED FOR A DEFERRED ITEM.

Narrative: ACFT WAS OPERATING UNDER MEL XA 'LEADING EDGE FLAP/SLAT SYS' AND WAS AN ORIGINATOR. MY ASSIGNED CAPT HAD BEEN RERTED, AND A NEW CAPT WAS ENRTE, DEADHEADING. I NOTED THE LOGBOOK MEL WRITE-UP AND BRIEFLY REVIEWED THE MEL DESCRIPTION PROVIDED BY THE OPS AGENT. THE MEL WAS 3 PAGES LONG, AND I DID NOT TAKE THE TIME TO THOROUGHLY READ IT, AS I HAD PREFLT DUTIES TO ACCOMPLISH AND ASSUMED THE CAPT WOULD REVIEW IT AND DECIDE WHAT ACTIONS, IF ANY, WERE REQUIRED. CAPT ARRIVED LATE. REVIEWED THE LOGBOOK AND MEL, AND COMPLETED HIS CHKS. WHEN DONE, HE DESCRIBED THE PROC FOR HANDLING THE MEL'ED FLAP/SLAT SYS: WITH THE 'STALL WARNING ASYMMETRY MODE' CIRCUIT BREAKERS COLLARED, WE COULD PROCEED NORMALLY IF THE FORWARD PANEL 'LEADING EDGE FLAPS TRANSIT' LIGHTS AND OVERHEAD LEADING EDGE DEVICE ANNUNCIATOR PANEL LIGHTS EXTINGUISHED PRIOR TO DEP. AS I RECALL, I CONCURRED WITH THIS CONCLUSION, AND WE BOTH NOTED THE LIGHTS INDICATED NORMAL SOMETIME BTWN THE AFTER START AND THE PRE START CHKLISTS AT LAS. THE CAPT AGREED WITH MY CONCLUSIONS REGARDING FL230. IT WAS AFTER THE SEQUENCE WAS COMPLETED AT ZZZ THAT THE CAPT CALLED TO INFORM ME OF OUR ERROR. (HE AND THE ONCOMING CAPT DISCUSSED IT DURING MY CAPT'S DEADHEADING FLT HOME). IN FACT, THE MEL REQUIRES THAT IF BOTH THE FORWARD PANEL AND ANNUNCIATOR LIGHTS ARE 'INOP' (AND PLACARDED) THAT SPD/ALT RESTRS APPLY REGARDLESS OF LIGHT STATUS. I ERRED IN NOT TAKING THE TIME TO READ THE MEL AND DETERMINE WHICH SCENARIO OF THE SEVERAL LISTED APPLIED TO OUR ACFT. THE NEXT DAY, I NOTED THE KEY WORDS 'OR' AND 'AND, IN ADDITION' (REFERRING TO FORWARD PANEL AND OVERHEAD ANNUNCIATOR LIGHTS) ARE ALL THAT MODIFY OTHERWISE IDENTICAL LANGUAGE IN THE DESCRIPTIVE SENTENCES OF THE SEVERAL SECTIONS OF THIS MEL. I RECALL READING OVER THE FIRST SECTION, MISSING THE WORD 'OR' AND ASSUMING IT APPLIED TO US. WHEN THE CAPT ANNOUNCED THAT WAS THE COURSE OF ACTION WE WOULD TAKE (HE CAME TO THE SAME CONCLUSION I DID), THE HOOK WAS SET. IN THE FUTURE, I WILL THOROUGHLY REVIEW EACH MEL AND LOGBOOK ENTRY (WHETHER I AM THE PIC OR NOT), AND DISCUSS IT WITH THE OTHER PLT TO BE SURE BOTH OF US COMPLETELY UNDERSTAND AND AGREE ON THE REQUIRED COURSE OF ACTION. THIS MEL WAS PARTICULARLY DIFFICULT TO READ AND UNDERSTAND, AND I BELIEVE THAT CONTRIBUTED TO OUR ERROR. IF THERE WERE SOME WAY TO HIGHLIGHT OR POINT OUT EXACTLY WHICH AREA OF AN MEL APPLIED TO AN ACFT (IE, A SPD/ALT RESTR), IT WOULD VASTLY REDUCE THE ODDS OF A FLC TAKING THE WRONG COURSE OF ACTION.

Data retrieved from NASA's ASRS site as of July 2007 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.