Clearance confusion.

Attributes
ACN	306390
Time
Date	199505
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : lax
State Reference	CA
Altitude	msl bound lower : 26000 msl bound upper : 28000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zla
Operator	common carrier : air carrier
Make Model Name	L-1011 Tri-Star All Series
Operating Under FAR Part	Part 121
Flight Phase	descent other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : commercial pilot : atp
Experience	flight time last 90 days : 150 flight time total : 20000 flight time type : 8000
ASRS Report	306390
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	altitude deviation : overshoot non adherence : clearance other anomaly other
Independent Detector	other controllera
Resolutory Action	other
Consequence	Other
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	other

Narrative:

Cruising at FL350 en route to lax from stl. ZLA cleared us to FL240. Started descent. Was switched to another ZLA frequency. Center instructed us to turn to a heading off airway for spacing into lax, then instructed us to indicate 250 KTS at FL280. Through FL266 ATC question our altitude, told us to level at FL260, we did. He said our descent clearance was to FL280. I told him we never received that clearance nor did I ever read back such. The confusion of 'indicating 250 KTS at FL280' clearance contributed to this event. No conflict occurred.

Original NASA ASRS Text

Title: CLRNC CONFUSION.

Narrative: CRUISING AT FL350 ENRTE TO LAX FROM STL. ZLA CLRED US TO FL240. STARTED DSCNT. WAS SWITCHED TO ANOTHER ZLA FREQ. CTR INSTRUCTED US TO TURN TO A HDG OFF AIRWAY FOR SPACING INTO LAX, THEN INSTRUCTED US TO INDICATE 250 KTS AT FL280. THROUGH FL266 ATC QUESTION OUR ALT, TOLD US TO LEVEL AT FL260, WE DID. HE SAID OUR DSCNT CLRNC WAS TO FL280. I TOLD HIM WE NEVER RECEIVED THAT CLRNC NOR DID I EVER READ BACK SUCH. THE CONFUSION OF 'INDICATING 250 KTS AT FL280' CLRNC CONTRIBUTED TO THIS EVENT. NO CONFLICT OCCURRED.

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.