Large transport crew had altitude overshoot in ZOA class a.

Attributes
ACN	486092
Time
Date	200009
Day	Fri
Local Time Of Day	1801 To 2400
Place
Locale Reference	navaid : lin.vortac
State Reference	CA
Altitude	msl bound lower : 21000 msl bound upper : 23000
Environment
Flight Conditions	VMC
Light	Dusk
Aircraft 1
Controlling Facilities	artcc : zoa.artcc
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 2 Turbojet Eng
Operating Under FAR Part	Part 121
Flight Phase	climbout : vacating altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : cfi pilot : flight engineer pilot : multi engine pilot : instrument
Experience	flight time last 90 days : 80 flight time total : 14000 flight time type : 2000
ASRS Report	486092
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : multi engine pilot : instrument pilot : flight engineer pilot : commercial pilot : atp
Experience	flight time last 90 days : 90 flight time total : 4000 flight time type : 1000
ASRS Report	486090
Events
Anomaly	altitude deviation : overshoot non adherence : clearance non adherence : published procedure other anomaly other
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance controller : issued alert
Supplementary
Problem Areas	Flight Crew Human Performance ATC Human Performance
Primary Problem	Ambiguous

Narrative:

We were given a clearance to FL230. We acknowledged the clearance by saying, 'air carrier abcd cleared to FL230.' we set our altitude alerter to 23000 ft and both confirmed FL230 on our primary flight displays. A short time later we were given a turn to 040 degrees, acknowledged it, and made the turn. While climbing through FL221, the controller said 'air carrier abcd it looks like you went through FL210, you are now cleared to FL230.' we said, 'we did not receive a clearance to FL210 and that we were already cleared to FL230.' a possible contributing factor may have been that there were 2 other air carrier flts, eastbound on frequency. They were air carrier abce and air carrier abcf.

Original NASA ASRS Text

Title: LGT CREW HAD ALT OVERSHOOT IN ZOA CLASS A.

Narrative: WE WERE GIVEN A CLRNC TO FL230. WE ACKNOWLEDGED THE CLRNC BY SAYING, 'ACR ABCD CLRED TO FL230.' WE SET OUR ALT ALERTER TO 23000 FT AND BOTH CONFIRMED FL230 ON OUR PRIMARY FLT DISPLAYS. A SHORT TIME LATER WE WERE GIVEN A TURN TO 040 DEGS, ACKNOWLEDGED IT, AND MADE THE TURN. WHILE CLBING THROUGH FL221, THE CTLR SAID 'ACR ABCD IT LOOKS LIKE YOU WENT THROUGH FL210, YOU ARE NOW CLRED TO FL230.' WE SAID, 'WE DID NOT RECEIVE A CLRNC TO FL210 AND THAT WE WERE ALREADY CLRED TO FL230.' A POSSIBLE CONTRIBUTING FACTOR MAY HAVE BEEN THAT THERE WERE 2 OTHER ACR FLTS, EBOUND ON FREQ. THEY WERE ACR ABCE AND ACR ABCF.

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.