An air carrier large transport began a descent to FL200 vice turning to heading 200.

Attributes
ACN	242531
Time
Date	199305
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : dqn
State Reference	OH
Altitude	msl bound lower : 21000 msl bound upper : 22000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zid
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	cruise other descent other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : commercial pilot : atp pilot : private
Experience	flight time last 90 days : 180 flight time total : 16000 flight time type : 180
ASRS Report	242531
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Experience	flight time last 90 days : 90 flight time total : 6000 flight time type : 1500
ASRS Report	242686
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other other spatial deviation
Independent Detector	other controllera other flight crewa
Resolutory Action	flight crew : became reoriented flight crew : returned to intended course or assigned course
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Captain received radio call to turn to heading 200 degrees. I (captain) told first officer heading 200 degrees. First officer had not heard the original heading xmissions. After telling first officer of the turn, I turned and conferred with the so about the fuel. When I looked back, the first officer had left FL220 for FL200 thinking I had meant change altitude rather than heading. We immediately climbed back to FL220 and conferred with center about the deviation. The obvious corrective action is good communication and make sure of complete understanding before taking action.

Original NASA ASRS Text

Title: AN ACR LGT BEGAN A DSCNT TO FL200 VICE TURNING TO HDG 200.

Narrative: CAPT RECEIVED RADIO CALL TO TURN TO HDG 200 DEGS. I (CAPT) TOLD FO HDG 200 DEGS. FO HAD NOT HEARD THE ORIGINAL HDG XMISSIONS. AFTER TELLING FO OF THE TURN, I TURNED AND CONFERRED WITH THE SO ABOUT THE FUEL. WHEN I LOOKED BACK, THE FO HAD LEFT FL220 FOR FL200 THINKING I HAD MEANT CHANGE ALT RATHER THAN HDG. WE IMMEDIATELY CLBED BACK TO FL220 AND CONFERRED WITH CTR ABOUT THE DEV. THE OBVIOUS CORRECTIVE ACTION IS GOOD COM AND MAKE SURE OF COMPLETE UNDERSTANDING BEFORE TAKING ACTION.

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.