B737-400 cleared to descend then immediately cleared to return to vacated altitude.

Attributes
ACN	321740
Time
Date	199511
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : pdz
State Reference	CA
Altitude	msl bound lower : 15600 msl bound upper : 16000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zla tower : acy
Operator	common carrier : air carrier
Make Model Name	B737-400
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
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 : atp pilot : cfi pilot : commercial pilot : flight engineer pilot : instrument
Experience	flight time last 90 days : 350 flight time total : 10000 flight time type : 1000
ASRS Report	321740
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial pilot : atp
Events
Anomaly	other anomaly other
Independent Detector	other controllera other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course other
Consequence	Other
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	other

Narrative:

Level at 16000 ft, center cleared us to descend to 15000 ft. I read back 'vacating 16000 ft for 15000 ft.' at approximately 15700 ft center controller (a different voice, this time) states 'climb to and maintain 16000 ft.' I read back 'we'll get right back to 16000 ft.' lowest descent was 15600 ft. Shortly thereafter controller states 'sorry about the late call.' first controller returns to frequency and worked our flight to next handoff. No conflicts noted by us with other aircraft.

Original NASA ASRS Text

Title: B737-400 CLRED TO DSND THEN IMMEDIATELY CLRED TO RETURN TO VACATED ALT.

Narrative: LEVEL AT 16000 FT, CTR CLRED US TO DSND TO 15000 FT. I READ BACK 'VACATING 16000 FT FOR 15000 FT.' AT APPROX 15700 FT CTR CTLR (A DIFFERENT VOICE, THIS TIME) STATES 'CLB TO AND MAINTAIN 16000 FT.' I READ BACK 'WE'LL GET RIGHT BACK TO 16000 FT.' LOWEST DSCNT WAS 15600 FT. SHORTLY THEREAFTER CTLR STATES 'SORRY ABOUT THE LATE CALL.' FIRST CTLR RETURNS TO FREQ AND WORKED OUR FLT TO NEXT HDOF. NO CONFLICTS NOTED BY US WITH OTHER ACFT.

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.