Altitude bust on approach.

Attributes
ACN	267476
Time
Date	199404
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : ont
State Reference	CA
Altitude	msl bound lower : 3800 msl bound upper : 4200
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : ont tracon : bur
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	cruise other descent : approach
Route In Use	approach : straight in
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 250 flight time total : 6500 flight time type : 250
ASRS Report	267476
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other
Independent Detector	other flight crewa
Resolutory Action	none taken : detected after the fact
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

On approach to ont at 4200 ft on localizer for runway 26L (not cleared for approach) controller issued traffic alert for aircraft passing to our left. (This was following hectic descent with many TCASII advisories.) we subsequently were confused as to whether we were cleared approach. First officer thought we were -- I wasn't sure. Radio was clogged with many light aircraft calls and by the time we confirmed no clearance, first officer had descended about 400 ft. Subsequently confirmed reclrnc for approach. Normal descent, no conflict mentioned by controller. Contributing factor, -- multiple TCASII activity and tons of light traffic radio chatter preventing quick confirmation with ATC. Also, brand new captain and 6 month first officer.

Original NASA ASRS Text

Title: ALT BUST ON APCH.

Narrative: ON APCH TO ONT AT 4200 FT ON LOC FOR RWY 26L (NOT CLRED FOR APCH) CTLR ISSUED TFC ALERT FOR ACFT PASSING TO OUR L. (THIS WAS FOLLOWING HECTIC DSCNT WITH MANY TCASII ADVISORIES.) WE SUBSEQUENTLY WERE CONFUSED AS TO WHETHER WE WERE CLRED APCH. FO THOUGHT WE WERE -- I WASN'T SURE. RADIO WAS CLOGGED WITH MANY LIGHT ACFT CALLS AND BY THE TIME WE CONFIRMED NO CLRNC, FO HAD DSNDED ABOUT 400 FT. SUBSEQUENTLY CONFIRMED RECLRNC FOR APCH. NORMAL DSCNT, NO CONFLICT MENTIONED BY CTLR. CONTRIBUTING FACTOR, -- MULTIPLE TCASII ACTIVITY AND TONS OF LIGHT TFC RADIO CHATTER PREVENTING QUICK CONFIRMATION WITH ATC. ALSO, BRAND NEW CAPT AND 6 MONTH FO.

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.