Aircraft programmed to cross baton 9000. Began climb at 10000.

Attributes
ACN	185153
Time
Date	199108
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : buj airport : dfw
State Reference	TX
Altitude	msl bound lower : 9000 msl bound upper : 10400
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : dfw
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other
Flight Phase	descent other
Route In Use	arrival star : star
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : flight engineer pilot : commercial
Experience	flight time last 90 days : 60 flight time total : 160 flight time type : 30
ASRS Report	185153
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : crossing restriction not met altitude deviation : undershoot non adherence : clearance
Independent Detector	other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course none taken : anomaly accepted
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

Descending into dfw on the blue ridge STAR with a clearance to cross blue ridge at or above 11000 ft and baton at 9000 ft. With FMS engaged in VNAV and altitude alert window set at 9000 ft aircraft leveled off at 10000 ft (aircraft location was beyond blue ridge but prior to baton). The automatic throttles then commanded climb power and aircraft pitched up about 7 degree. Aircraft did not respond to autoplt inputs at which time it was disconnected. Aircraft reached 10400 ft before I got the nose over to continue the descent to 9000 ft. I am still not sure what caused the level off/climb by the autoplt/automatic throttles. The FMS was programmed to cross blue ridge at or above 11000 and baton at 9000. All indications on the pfd were that the descent profile was normal. Callback conversation with reporter revealed the following information: the medium large transport FMS is programmed to slow the aircraft to 240 IAS at 10000 ft before continuing descent to an altitude below 10000. Does not explain why the aircraft added power and began a climb however.

Original NASA ASRS Text

Title: ACFT PROGRAMMED TO CROSS BATON 9000. BEGAN CLB AT 10000.

Narrative: DSNDING INTO DFW ON THE BLUE RIDGE STAR WITH A CLRNC TO CROSS BLUE RIDGE AT OR ABOVE 11000 FT AND BATON AT 9000 FT. WITH FMS ENGAGED IN VNAV AND ALT ALERT WINDOW SET AT 9000 FT ACFT LEVELED OFF AT 10000 FT (ACFT LOCATION WAS BEYOND BLUE RIDGE BUT PRIOR TO BATON). THE AUTO THROTTLES THEN COMMANDED CLB PWR AND ACFT PITCHED UP ABOUT 7 DEG. ACFT DID NOT RESPOND TO AUTOPLT INPUTS AT WHICH TIME IT WAS DISCONNECTED. ACFT REACHED 10400 FT BEFORE I GOT THE NOSE OVER TO CONTINUE THE DSCNT TO 9000 FT. I AM STILL NOT SURE WHAT CAUSED THE LEVEL OFF/CLB BY THE AUTOPLT/AUTO THROTTLES. THE FMS WAS PROGRAMMED TO CROSS BLUE RIDGE AT OR ABOVE 11000 AND BATON AT 9000. ALL INDICATIONS ON THE PFD WERE THAT THE DSCNT PROFILE WAS NORMAL. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFORMATION: THE MLG FMS IS PROGRAMMED TO SLOW THE ACFT TO 240 IAS AT 10000 FT BEFORE CONTINUING DSCNT TO AN ALT BELOW 10000. DOES NOT EXPLAIN WHY THE ACFT ADDED PWR AND BEGAN A CLB HOWEVER.

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.