<< >> NASA ASRS Report 1035573, September 2012

While descending in VNAV to cross zizzi at 16;000 ft; the flight crew of an E-145 had to manually return the aircraft to its programmed crossing restriction when the autopilot failed to capture the altitude. A known FMS software flaw; currently under review; may have been a contributing factor.

Attributes
ACN	1035573
Time
Date	201209
Local Time Of Day	1801-2400
Place
Locale Reference	DCA.Airport
State Reference	DC
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	EMB ERJ 170/175 ER/LR
Operating Under FAR Part	Part 121
Flight Phase	Descent
Flight Plan	IFR
Component
Aircraft Component	FMS/FMC
Person 1
Function	Pilot Not Flying Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Person 2
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Altitude Overshoot Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy

Narrative:

ATC cleared us to cross zizzi at 16;000 ft. We acknowledged altitude descending through 17;000 ft with altitude alerter aural indication and flashing yellow indication in altitude select box on pfd. I resumed briefing the river visual approach. The aircraft descended through 16;000 ft in VNAV with autopilot engaged. The flying pilot disengaged the autopilot and corrected altitude to 16;000 ft immediately. I notified ATC that we had an autopilot malfunction and that we were correcting altitude.to 'prevent' this type of event; I feel that VNAV operations could be suspended until the software load is updated to prevent the unanticipated occurrence of altitude select malfunctions as a function of VNAV operations.

Related reports:

• Emb-175 captain reported they overshot a crossing restrictio...

	Enter your search terms Submit search form
	Web www.37000feet.com

Original NASA ASRS Text

Title: While descending in VNAV to cross ZIZZI at 16;000 FT; the flight crew of an E-145 had to manually return the aircraft to its programmed crossing restriction when the autopilot failed to capture the altitude. A known FMS software flaw; currently under review; may have been a contributing factor.

Narrative: ATC cleared us to cross ZIZZI at 16;000 FT. We acknowledged altitude descending through 17;000 FT with altitude alerter aural indication and flashing yellow indication in altitude select box on PFD. I resumed briefing the river visual approach. The aircraft descended through 16;000 FT in VNAV with autopilot engaged. The flying pilot disengaged the autopilot and corrected altitude to 16;000 FT immediately. I notified ATC that we had an autopilot malfunction and that we were correcting altitude.To 'prevent' this type of event; I feel that VNAV operations could be suspended until the software load is updated to prevent the unanticipated occurrence of ALT Select malfunctions as a function of VNAV operations.

Data retrieved from NASA's ASRS site as of July 2013 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.