Flight failed to comply with crossing altitude restriction while flying arrival STAR.

Attributes
ACN	110571
Time
Date	198905
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : eca
State Reference	CA
Altitude	msl bound lower : 11000 msl bound upper : 18000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	descent other
Route In Use	arrival other arrival star : star enroute airway : zoa
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 240 flight time total : 10000
ASRS Report	110571
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	altitude deviation : crossing restriction not met altitude deviation : undershoot non adherence : clearance other anomaly
Independent Detector	other flight crewa
Resolutory Action	none taken : unable
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

We were cleared to cross cedes at 11000'. We were descending from above 23000' and had programmed the FMS to cross cedes at 11000'/250 KTS. At 18000' it became obvious that we wouldn't be able to make the cross point at the correct altitude or speed. We disconnected the FMS and attempted to manually reach the altitude and airspeed. We attempted to call ATC and inform them of the problem, but the frequency was busy. We crossed the point (cedes) slightly high and fast. No conflict developed with other traffic (that we know of), but this problem seems to develop in the FMS when a new cruise altitude is entered after a crossing restriction is entered. Example: when cruising at 26000' you're cleared to 'cross cedes at 11000', 250 KIAS.' the aircraft is not ready to descend yet, so you remain at 26000' with automatic VNAV set to cross cedes (11000/250). Later the controller says to, 'descend to 23000' now, discretion to cross cedes 11000/250.' it seems that if you select FL230 as a new cruise altitude, the FMS 'forgets' about its crossing fix until it reaches the new cruise altitude. It normally only descends at about 1000 FPM to the new cruise altitude, so in the meantime it passes above its descent path to the crossing fix. We hope this makes some sense and that it will be of help.

Original NASA ASRS Text

Title: FLT FAILED TO COMPLY WITH CROSSING ALT RESTRICTION WHILE FLYING ARR STAR.

Narrative: WE WERE CLRED TO CROSS CEDES AT 11000'. WE WERE DSNDING FROM ABOVE 23000' AND HAD PROGRAMMED THE FMS TO CROSS CEDES AT 11000'/250 KTS. AT 18000' IT BECAME OBVIOUS THAT WE WOULDN'T BE ABLE TO MAKE THE CROSS POINT AT THE CORRECT ALT OR SPD. WE DISCONNECTED THE FMS AND ATTEMPTED TO MANUALLY REACH THE ALT AND AIRSPD. WE ATTEMPTED TO CALL ATC AND INFORM THEM OF THE PROB, BUT THE FREQ WAS BUSY. WE CROSSED THE POINT (CEDES) SLIGHTLY HIGH AND FAST. NO CONFLICT DEVELOPED WITH OTHER TFC (THAT WE KNOW OF), BUT THIS PROB SEEMS TO DEVELOP IN THE FMS WHEN A NEW CRUISE ALT IS ENTERED AFTER A XING RESTRICTION IS ENTERED. EXAMPLE: WHEN CRUISING AT 26000' YOU'RE CLRED TO 'CROSS CEDES AT 11000', 250 KIAS.' THE ACFT IS NOT READY TO DSND YET, SO YOU REMAIN AT 26000' WITH AUTOMATIC VNAV SET TO CROSS CEDES (11000/250). LATER THE CTLR SAYS TO, 'DSND TO 23000' NOW, DISCRETION TO CROSS CEDES 11000/250.' IT SEEMS THAT IF YOU SELECT FL230 AS A NEW CRUISE ALT, THE FMS 'FORGETS' ABOUT ITS XING FIX UNTIL IT REACHES THE NEW CRUISE ALT. IT NORMALLY ONLY DESCENDS AT ABOUT 1000 FPM TO THE NEW CRUISE ALT, SO IN THE MEANTIME IT PASSES ABOVE ITS DSCNT PATH TO THE XING FIX. WE HOPE THIS MAKES SOME SENSE AND THAT IT WILL BE OF HELP.

Data retrieved from NASA's ASRS site as of August 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.