Air carrier flight crew reports descending below 11000 feet approaching delmo on the BOOVE1 RNAV arr...

Narrative:

We were cleared to 'descend via' on the boove one arrival; into dfw. The plane was descending in VNAV on the arrival with 8;000 set in the altitude window for lreee. VNAV worked properly making all the altitude windows and airspeed reductions through mowww during the descent. The autopilot leveled the plane at 11;000 feet and slowed to 220 knots approaching delmo intersection. Approximately 3 miles prior to delmo; the plane began a descent; violating the clearance/crossing altitude. The autopilot was disengaged and we climbed back up to 11;000 feet. The FMC had 11;000 feet and 220 knots displayed as restrictions at delmo. This came up when we selected the approach and was not edited by the flight crew. There seems to be a problem with the FMS database or autopilot interface. Reading F4 messages; it is obvious that there are problems with the arrivals into dfw. While the boove is not listed; others are with the same problem; seemingly always descending improperly from 11;000. The easy solution is to set 11;000 in the altitude window anytime VNAV is used on arrivals into dfw until passing the 11;000 foot waypoint. Then don't use VNAV anymore on the arrival. That message should be sent to all pilots; in a place we are likely to see and read it.

Original NASA ASRS Text

Title: Air carrier flight crew reports descending below 11000 feet approaching DELMO on the BOOVE1 RNAV arrival to DFW. The aircraft had been descending in LNAV and VNAV with the DELMO restrictions in the FMC. After a 400 foot deviation the flying First Officer returned to 11;000 feet.

Narrative: We were cleared to 'descend via' on the BOOVE one arrival; into DFW. The plane was descending in VNAV on the arrival with 8;000 set in the altitude window for LREEE. VNAV worked properly making all the altitude windows and airspeed reductions through MOWWW during the descent. The autopilot leveled the plane at 11;000 feet and slowed to 220 knots approaching DELMO intersection. Approximately 3 miles prior to DELMO; the plane began a descent; violating the clearance/crossing altitude. The autopilot was disengaged and we climbed back up to 11;000 feet. The FMC had 11;000 feet and 220 knots displayed as restrictions at DELMO. This came up when we selected the approach and was not edited by the flight crew. There seems to be a problem with the FMS database or autopilot interface. Reading F4 messages; it is obvious that there are problems with the arrivals into DFW. While the BOOVE is not listed; others are with the same problem; seemingly always descending improperly from 11;000. The easy solution is to set 11;000 in the altitude window anytime VNAV is used on arrivals into DFW until passing the 11;000 foot waypoint. Then don't use VNAV anymore on the arrival. That message should be sent to all pilots; in a place we are likely to see and read it.

Data retrieved from NASA's ASRS site 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	1223347
Time
Date	201412
Local Time Of Day	1801-2400
Place
Locale Reference	D10.TRACON
State Reference	TX
Aircraft 1
Make Model Name	Boeing Company Undifferentiated or Other Model
Flight Phase	Descent
Route In Use	STAR BOOVE1
Flight Plan	IFR
Component
Aircraft Component	Autoflight System
Person 1
Function	Pilot Flying First Officer
Qualification	Flight Crew Air Transport Pilot (ATP)
Person 2
Function	Pilot Not Flying Captain
Experience	Flight Crew Total 24991
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy

Air carrier flight crew reports descending below 11000 feet approaching delmo on the BOOVE1 RNAV arrival to dfw. The aircraft had been descending in LNAV and VNAV with the delmo restrictions in the FMC. After a 400 foot deviation the flying first officer returned to 11;000 feet.