Altitude deviation altitude undershot on descent. Altitude crossing restr not met.

Attributes
ACN	307312
Time
Date	199506
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : sea
State Reference	WA
Altitude	msl bound lower : 16000 msl bound upper : 16500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zse
Operator	common carrier : air carrier
Make Model Name	A320
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	descent other
Route In Use	arrival other arrival star : star enroute airway : zse
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 225 flight time total : 10000 flight time type : 1800
ASRS Report	307312
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : undershoot altitude deviation : crossing restriction not met non adherence : clearance non adherence : published procedure other anomaly other
Independent Detector	other flight crewa
Resolutory Action	none taken : insufficient time
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

On descent chins 2 arrival, instructed to cross snomy at 16000 ft. Inserted 16000 ft into vertical navigation. Then, after inserting runway 16R ILS into database, discovered database ILS heading wrong. Manually programmed ILS. When this was done, the vertical navigation crossing restr dropped out, since raddy was 'to' waypoint and snomy next (but only 6.5 mi away). Aircraft went to vertical speed and crossed snomy 500 ft high. When using vertical navigation with a constraint, that constraint drops out even though it is the constraint to which the aircraft is operating. This is a software programming problem and should be corrected.

Original NASA ASRS Text

Title: ALTDEV ALT UNDERSHOT ON DSCNT. ALT XING RESTR NOT MET.

Narrative: ON DSCNT CHINS 2 ARR, INSTRUCTED TO CROSS SNOMY AT 16000 FT. INSERTED 16000 FT INTO VERT NAV. THEN, AFTER INSERTING RWY 16R ILS INTO DATABASE, DISCOVERED DATABASE ILS HDG WRONG. MANUALLY PROGRAMMED ILS. WHEN THIS WAS DONE, THE VERT NAV XING RESTR DROPPED OUT, SINCE RADDY WAS 'TO' WAYPOINT AND SNOMY NEXT (BUT ONLY 6.5 MI AWAY). ACFT WENT TO VERT SPD AND CROSSED SNOMY 500 FT HIGH. WHEN USING VERT NAV WITH A CONSTRAINT, THAT CONSTRAINT DROPS OUT EVEN THOUGH IT IS THE CONSTRAINT TO WHICH THE ACFT IS OPERATING. THIS IS A SOFTWARE PROGRAMMING PROB AND SHOULD BE CORRECTED.

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.