B717 first officer experiences mcdu lock-up during taxi out. Maintenance control advises that turnin...

Narrative:

During passenger boarding; ground power was temporarily disconnected and then came back online. Everything seemed to be working fine at that point. After pushback and engine start; during taxi; we noticed that the mcdu's were locking up and when we tried to change pages; it would return to the same page. Prior to takeoff; we called maintenance control to discuss it with them. The maintenance controller had us turn off the afs [autoflight system] (the paddles) to see if that unfroze the mcdu's. It did; but when the afs was turned back on the mcdu's froze again. The maintenance controller informed us that we could take off with the afs turned off and then turn it back on after takeoff and that would make the mcdu's work. The captain verified with him that no logbook write-up was required and the maintenance controller told him that it was not and that this was the new procedure that was going to be added to the aom for a mcdu lock-up. We continued the flight and took off with the afs turned off. After takeoff we turned the afs back on and the mcdu's still locked up. We continued the flight with the afs turned off. After we reached our assigned cruise altitude of FL310; we remembered that we were not rvsm qualified without an autoflight system. Upon discovering that; we requested to leave rvsm airspace with ATC; and were assigned a lower altitude. We landed uneventfully.we were in a bit of a hurry to leave because a vip was scheduled to land there at any minute and we did not want to delay the flight by getting stuck when the airport got shut down. But the procedure given by maintenance control for a mcdu lock-up does not work all the time and should not be given to pilots as an approved procedure. We should not have rushed and should have taken the time to shut the whole system down and reset it but we were following the information given by maintenance control.

Original NASA ASRS Text

Title: B717 First Officer experiences MCDU lock-up during taxi out. Maintenance Control advises that turning off the AFS for takeoff will allow normal MCDU operation. After takeoff normal MCDU operation cannot be restored with AFS on and is turned off. Crew requests descent out of RVSM airspace.

Narrative: During passenger boarding; ground power was temporarily disconnected and then came back online. Everything seemed to be working fine at that point. After pushback and engine start; during taxi; we noticed that the MCDU's were locking up and when we tried to change pages; it would return to the same page. Prior to takeoff; we called Maintenance Control to discuss it with them. The Maintenance Controller had us turn off the AFS [Autoflight System] (the paddles) to see if that unfroze the MCDU's. It did; but when the AFS was turned back on the MCDU's froze again. The Maintenance Controller informed us that we could take off with the AFS turned off and then turn it back on after takeoff and that would make the MCDU's work. The Captain verified with him that no logbook write-up was required and the Maintenance Controller told him that it was not and that this was the new procedure that was going to be added to the AOM for a MCDU lock-up. We continued the flight and took off with the AFS turned off. After takeoff we turned the AFS back on and the MCDU's still locked up. We continued the flight with the AFS turned off. After we reached our assigned cruise altitude of FL310; we remembered that we were not RVSM qualified without an Autoflight System. Upon discovering that; we requested to leave RVSM airspace with ATC; and were assigned a lower altitude. We landed uneventfully.We were in a bit of a hurry to leave because a VIP was scheduled to land there at any minute and we did not want to delay the flight by getting stuck when the airport got shut down. But the procedure given by Maintenance Control for a MCDU lock-up does not work all the time and should not be given to pilots as an approved procedure. We should not have rushed and should have taken the time to shut the whole system down and reset it but we were following the information given by Maintenance Control.

Data retrieved from NASA's ASRS site as of April 2012 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.

Attributes
ACN	910766
Time
Date	201009
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	B717 (Formerly MD-95)
Operating Under FAR Part	Part 121
Flight Phase	Taxi
Component
Aircraft Component	FMS/FMC
Person 1
Function	First Officer Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Published Material / Policy Deviation - Procedural FAR

B717 first officer experiences mcdu lock-up during taxi out. Maintenance control advises that turning off the afs for takeoff will allow normal mcdu operation. After takeoff normal mcdu operation cannot be restored with afs on and is turned off. Crew requests descent out of rvsm airspace.