B737-800
Flight Crew Air Transport Pilot (ATP)
Confusion; Workload; Distraction
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural MEL / CDL; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Became Reoriented; General Maintenance Action
Aircraft; Manuals; Procedure
MEL 32-2b was added after return to gate. Anti skid system Inop. Low visibility takeoff and CAT 2 or 3 operations are not allowed. Maintenance did not downgrade the aircraft to CAT1 status. After level off we realized that this action was not performed and the 'screw' was not moved from the CAT 3 position. Not CAT 2 or 3 operations were performed.Did not realize screw was not moved.
I was called to an aircraft about the anti-skid inop light coming on after pushback. I was told it was coming back to the gate as a block turn back. I was called on the radio and told that Maintenance Control has authorized MEL 32-2B for the anti-skid system. When I spoke with the Captain he told me the anti-skid inop light had extinguished before he reached the gate. The MEL states that the inop channel must be isolated and deactivated. Since the light had extinguished I ran a bite test to determine which channel had failed. The anti-skid control module did not show any faults. I called Maintenance Control and spoke with a controller. I asked him if the MEL was valid since I was not able to determine the bad channel. We discussed the matter and he pointed out to me in the maintenance procedure that if the bad channel could not be isolated to deactivate both channels. So I called my Supervisor to verify that I complied with the maintenance procedures to pull and collar the inboard and outboard anti-skid C/B's on the P6-2 circuit breaker panel. I also noticed that the MEL notes state that the autobrakes and RTO will also be inop with those two C/B's pulled. I called back to Maintenance Control and asked if I needed to apply two additional MEL's. He told me that our procedures would state to only apply them if procedures called for it. I then completed the paper work and my Supervisor reviewed it. We both looked at it and determined it was good. The plane departed without incident. I discovered the error when I received a phone call asking me if I had downgraded the aircraft. He noticed at his shift change meeting that the aircraft was shown downgraded but no log page had been generated.I feel the event occurred because it was a block turn back. There was a sense of urgency to get the plane out as soon as possible. My attention was largely focused on getting the maintenance procedures correct. I wanted to make sure the plane would be safe with both inboard and outboard C/B's pulled. Since that MEL carries restrictions I wanted to make sure the configuration I put the aircraft in would allow it to fly safely. Adding to the urgency was the fact that I called Maintenance Control (ETOPS LINE) 4 times and was told all controllers are busy and to call back later. I called my Supervisor to find out if an alternate phone number was available. To his knowledge no other number was available. With each passing call the delay time increased. This led to a sense of urgency to get the airplane out. This was possibly the cause for my oversight.I received the news about the missed downgraded at the end of my shift. Since I ride in a van pool and am a driver was not able to stay past my shift to file a safety report. Maintenance Control told me that he would call maintenance at the next station and have them downgrade the aircraft when it arrived. A possible suggestion to avoid this mistake is possibly have any text in bold that directs you to initiate another log page in the MEL manual. Perhaps even some sort of flag that pops up on the Maintenance Controller's computer screen when additional action or log pages are required or generated.
A B737-800 returned to the gate with an Antiskid INOP indication and both systems were MEL'ED because the faulty system was not identified. In the rush to release the aircraft; the flight station downgrade was not accomplished.