Flight crew climbs to FL290 then told should be 2000' lower.

Attributes
ACN	154308
Time
Date	199008
Day	Fri
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : jax
State Reference	FL
Altitude	msl bound lower : 27000 msl bound upper : 29000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zjx
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 210 flight time total : 8000 flight time type : 450
ASRS Report	154308
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	altitude deviation : overshoot conflict : airborne less severe non adherence : required legal separation other anomaly other
Independent Detector	other controllera
Resolutory Action	flight crew : returned to intended course or assigned course
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

We had leveled off at FL290 for +/- 2 mins when jax center told us we had been cleared to climb to FL270 only. We were in traffic conflict and to descend to FL270 immediately. We were off the arwy (avoiding WX). Were not required to take evasive action and do not believe there was any serious conflict. Whether it was a mistake on the part of ATC or us, I do not know. We had understood FL290 and I believe the first officer read it back as such. I had climbed to FL290 as was dialed in the window.

Original NASA ASRS Text

Title: FLT CREW CLIMBS TO FL290 THEN TOLD SHOULD BE 2000' LOWER.

Narrative: WE HAD LEVELED OFF AT FL290 FOR +/- 2 MINS WHEN JAX CTR TOLD US WE HAD BEEN CLRED TO CLB TO FL270 ONLY. WE WERE IN TFC CONFLICT AND TO DSND TO FL270 IMMEDIATELY. WE WERE OFF THE ARWY (AVOIDING WX). WERE NOT REQUIRED TO TAKE EVASIVE ACTION AND DO NOT BELIEVE THERE WAS ANY SERIOUS CONFLICT. WHETHER IT WAS A MISTAKE ON THE PART OF ATC OR US, I DO NOT KNOW. WE HAD UNDERSTOOD FL290 AND I BELIEVE THE F/O READ IT BACK AS SUCH. I HAD CLBED TO FL290 AS WAS DIALED IN THE WINDOW.

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.