Altitude deviation crossing restr not met. VNAV constraint dropped out when inserting new constraint...

Attributes
ACN	319770
Time
Date	199510
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : otk
State Reference	GA
Altitude	msl bound lower : 27000 msl bound upper : 30000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zjx
Operator	common carrier : air carrier
Make Model Name	A320
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	descent other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : instrument pilot : commercial
Experience	flight time last 90 days : 75 flight time total : 22000 flight time type : 1600
ASRS Report	319770
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	altitude deviation : undershoot altitude deviation : crossing restriction not met non adherence : clearance other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	none taken : insufficient time
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Received clearance from ZJX to descend from FL370 to cross clawz intersection at FL270. Entered crossing restr in mcdu, selected constraint push button and set FL270 in altitude window, then pushed level change knob for a VNAV descent. Everything looked normal at this point and we should have intercepted the descent profile in about 2-3 min. Went back to mcdu and found the STAR approach plate to input leese crossing restr. Side note: flight attendant came into the cockpit just about this time to ask about something. The mcdu dropped the clawz crossing restr and would not allow it to be reinserted. Gave an error message that the input was outside of the correct range. At this point, we went to open descent using speed brakes in an attempt to make the crossing restr. Was unable to make FL270 until 5-6 NM past clawz due in part to an increase in the tailwind of an additional 25 KTS (105 vs 80-85). Crossed clawz at FL300 and was unable to contact center to advise as frequency had been quite busy with 4-5 other aircraft. No known conflicts, no comment from ZJX. Changed frequency a bit later. The airbus still does various things which are not logical nor easily explained. It seems as problems are corrected in the software others are created and some problems that supposedly have been fixed still exist under certain circumstances. Constant vigilance seems to be the only answer.

Original NASA ASRS Text

Title: ALTDEV XING RESTR NOT MET. VNAV CONSTRAINT DROPPED OUT WHEN INSERTING NEW CONSTRAINT.

Narrative: RECEIVED CLRNC FROM ZJX TO DSND FROM FL370 TO CROSS CLAWZ INTXN AT FL270. ENTERED XING RESTR IN MCDU, SELECTED CONSTRAINT PUSH BUTTON AND SET FL270 IN ALT WINDOW, THEN PUSHED LEVEL CHANGE KNOB FOR A VNAV DSCNT. EVERYTHING LOOKED NORMAL AT THIS POINT AND WE SHOULD HAVE INTERCEPTED THE DSCNT PROFILE IN ABOUT 2-3 MIN. WENT BACK TO MCDU AND FOUND THE STAR APCH PLATE TO INPUT LEESE XING RESTR. SIDE NOTE: FLT ATTENDANT CAME INTO THE COCKPIT JUST ABOUT THIS TIME TO ASK ABOUT SOMETHING. THE MCDU DROPPED THE CLAWZ XING RESTR AND WOULD NOT ALLOW IT TO BE REINSERTED. GAVE AN ERROR MESSAGE THAT THE INPUT WAS OUTSIDE OF THE CORRECT RANGE. AT THIS POINT, WE WENT TO OPEN DSCNT USING SPEED BRAKES IN AN ATTEMPT TO MAKE THE XING RESTR. WAS UNABLE TO MAKE FL270 UNTIL 5-6 NM PAST CLAWZ DUE IN PART TO AN INCREASE IN THE TAILWIND OF AN ADDITIONAL 25 KTS (105 VS 80-85). CROSSED CLAWZ AT FL300 AND WAS UNABLE TO CONTACT CTR TO ADVISE AS FREQ HAD BEEN QUITE BUSY WITH 4-5 OTHER ACFT. NO KNOWN CONFLICTS, NO COMMENT FROM ZJX. CHANGED FREQ A BIT LATER. THE AIRBUS STILL DOES VARIOUS THINGS WHICH ARE NOT LOGICAL NOR EASILY EXPLAINED. IT SEEMS AS PROBS ARE CORRECTED IN THE SOFTWARE OTHERS ARE CREATED AND SOME PROBS THAT SUPPOSEDLY HAVE BEEN FIXED STILL EXIST UNDER CERTAIN CIRCUMSTANCES. CONSTANT VIGILANCE SEEMS TO BE THE ONLY ANSWER.

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.