Narrative:

After descending and leveling at FL290 to comply with a crossing restriction, I was issued further clearance to FL250 by 'ZID', while some 30 DME south of tvt VOR. I selected 25000' on the mode control panel (MCP) and selected crz page on FMS CDU to enter 25000 on cruise descent page. I failed to reselect 'VNAV' which would have resulted in a descent at approximately 1000 FPM to FL250. As a result, we remained at FL290 with 'altitude hold' annunciated. It did not immediately come to my attention, as we (first officer, flight service manager and I), were discussing some events concerning a mentally deranged passenger who had earlier tried to force open the main cabin door while we began our pushback. (That resulted in an hour delay, police action, reports, etc which we were discussing as the fsm reviewed the comments in her report with me at the time I failed to begin my descent). While still at FL290, and a few mins later, the controller asked 'if we had started our descent to FL290.' I was confused at his question and asked the first officer to clarify if we were not cleared 'pilot's discretion to FL250.' the answer was were cleared to FL250 several mins earlier and he needed a good rate through FL270 for traffic. We hustled down to FL250. Leveling of, I asked the controller if there was a problem with our late descent. 'Not now' was his only response. The follow-up communication by the controller asking if we had started to descend to FL290 created some confusion. As we thought about it, we realized he was really meaning to ask if we had started down to FL250.

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Original NASA ASRS Text

Title: ACR MLG FLT CREW FAILS TO INITIATE DESCENT WHEN CLEARED.

Narrative: AFTER DSNDING AND LEVELING AT FL290 TO COMPLY WITH A XING RESTRICTION, I WAS ISSUED FURTHER CLRNC TO FL250 BY 'ZID', WHILE SOME 30 DME S OF TVT VOR. I SELECTED 25000' ON THE MODE CTL PANEL (MCP) AND SELECTED CRZ PAGE ON FMS CDU TO ENTER 25000 ON CRUISE DSNT PAGE. I FAILED TO RESELECT 'VNAV' WHICH WOULD HAVE RESULTED IN A DSNT AT APPROX 1000 FPM TO FL250. AS A RESULT, WE REMAINED AT FL290 WITH 'ALT HOLD' ANNUNCIATED. IT DID NOT IMMEDIATELY COME TO MY ATTN, AS WE (F/O, FLT SVC MGR AND I), WERE DISCUSSING SOME EVENTS CONCERNING A MENTALLY DERANGED PAX WHO HAD EARLIER TRIED TO FORCE OPEN THE MAIN CABIN DOOR WHILE WE BEGAN OUR PUSHBACK. (THAT RESULTED IN AN HR DELAY, POLICE ACTION, RPTS, ETC WHICH WE WERE DISCUSSING AS THE FSM REVIEWED THE COMMENTS IN HER RPT WITH ME AT THE TIME I FAILED TO BEGIN MY DSNT). WHILE STILL AT FL290, AND A FEW MINS LATER, THE CTLR ASKED 'IF WE HAD STARTED OUR DSNT TO FL290.' I WAS CONFUSED AT HIS QUESTION AND ASKED THE F/O TO CLARIFY IF WE WERE NOT CLRED 'PLT'S DISCRETION TO FL250.' THE ANSWER WAS WERE CLRED TO FL250 SEVERAL MINS EARLIER AND HE NEEDED A GOOD RATE THROUGH FL270 FOR TFC. WE HUSTLED DOWN TO FL250. LEVELING OF, I ASKED THE CTLR IF THERE WAS A PROB WITH OUR LATE DSNT. 'NOT NOW' WAS HIS ONLY RESPONSE. THE FOLLOW-UP COM BY THE CTLR ASKING IF WE HAD STARTED TO DSND TO FL290 CREATED SOME CONFUSION. AS WE THOUGHT ABOUT IT, WE REALIZED HE WAS REALLY MEANING TO ASK IF WE HAD STARTED DOWN TO FL250.

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.