MD-80 Series (DC-9-80) Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP)
Confusion
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural MEL / CDL; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Rejected Takeoff; Flight Crew Returned To Gate; General Flight Cancelled / Delayed; General Maintenance Action
MEL; Procedure; Aircraft
Upon arriving at work I observed that our aircraft was late inbound.  I sat and relaxed in the passenger waiting area.  The aircraft; arrived about a half hour late; if memory serves.  The Captain and I went out to the ramp.  The Captain initiated his walk around inspection and I conversed with the off-going first officer.  The off-going first officer informed me that the aircraft was 'good to go' except for an MEL item regarding the autospoiler system.  I boarded the aircraft and began the pre-departure procedures.  When the Captain entered the flight deck we discussed the MEL.  (27-XXX I believe)  We read the MEL and discussed the differing procedures and expectations regarding this write up.  During the 'Captains acceptance procedure' the Captain noted that he was getting the 'Auto Brakes' audible warning when testing the takeoff configuration warning system.  We discussed this result and determined that this warning should not be occurring during the takeoff configuration test with the auto spoiler system MEL'd.  Our thought was that we would not be able to take off if this warning operated as it was at the gate.  The Captain called maintenance and asked them to investigate our findings.  He also put a write-up in the maintenance logbook.  The maintenance technicians arrived and I exited the flight deck to allow more room for them to work.  After a few minutes; the technicians told us we could take off with this particular MEL so long as we 'select the auto brake system to take-off; but don't arm it; and you won't get the takeoff configuration warning.' This confused me since during the earlier review of this MEL we did not read anything about selecting the auto brake system to take off.  The Captain and I discussed this conclusion and agreed that the MEL as written would not allow us to takeoff in that configuration.  The technicians ultimately agreed with us and continued to trouble shoot the problem.  After multiple attempts to get the system to test properly; the technicians were able to get a normal test.  The write-up was signed off and we continued with departure procedures.  Push back; engine start and before taxi procedures were all normal as I recall.  We were cleared for takeoff.  At approximately the '80 knots; thrust normal' callout the 'autobrakes' takeoff configuration began to sound.  A rejected takeoff was initiated.  The rejected takeoff was performed; we exited the runway; notified ATC; notified the inflight crew that no action would be required from them; the QRH was consulted and the brake temperatures were checked per the brake over heat/rejected takeoff procedure.  We taxied to the gate without incident.  The rejected takeoff and deceleration to taxi speed were very gentle and even.  When we blocked in at the gate; I noted that the brake temperatures were approximately 170 to 180 degrees...lower than on most normal landings.  Maintenance technicians arrived at the aircraft and agreed that this particular aircraft should not be used in revenue service.  We ultimately swapped into another aircraft and completed the pairing without incident.  Later that day; or maybe the next day; I learned that the maintenance technicians had found a failed or displaced microswitch in the spoiler handle mechanism.  This type of failure could have caused worse outcomes if it had happened during different phases of flight.  When such an important system has failed in this manner and especially after being MEL'd causes an unexpected indication on the flight deck; much more attention should be paid to finding the cause of the unexpected indication rather than trying to push the airplane off the gate to get a flight segment completed.
Crew reported getting an Autobrakes Aural warning during taxi out takeoff warning checks. The aircraft had MEL 27-XXX already applied for a previous Auto Ground Spoiler discrepancy.I recommended the crew try putting the Auto Brakes selector knob in the TO position and re-check takeoff warning. The takeoff warning checks were now all good. The crew informed me that the autobrakes amber (ABS inop light) as now illuminated. I pointed out to the crew that per the applied MEL 27-00-19A 'Remarks or Exceptions' section; the autobrake system must remain disarmed and the autobrakes RTO mode would indeed be inop as the light now indicates and will not be used for takeoff. On takeoff roll; the crew reported getting an aural Autospoilers takeoff warning ['auto brakes' takeoff configuration warning] and they aborted takeoff and returned to gate for maintenance.MD-88 MEL 27-XXX specifies the Auto Brake system is not to be 'Armed' for takeoff; but has no instructions included in either 'M' or 'O' procedures on what position the Auto Brake mode selector knob should be in. MEL 27-XXX requires clarification on which position the Autobrake selector knob should be in for dispatch. Looking at the system schematics and wiring diagrams and maintenance manuals; it appears that when MEL 27-XXX is applied; an Autobrake or Autospoiler takeoff aural warning could sound in any autobrake selector position (including off) depending upon how certain associated autospoiler system components have failed. More research needed to determine which failure situation/autobrake selector knob position(s) should be allowed when MEL 27-XXX is being used. Investigation in progress.
MD-88 flight crew and the Maintenance Technician involved describe an AutoSpoiler deferral (MEL 27-XXX) that seems to cause an autobrake takeoff warning when tested at the gate. After much checking and testing the aircraft is signed off and functions normally until 80 knots in the takeoff roll when the AutoBrake warning sounds and the takeoff is rejected.