Pilot executes 30 degree west turn instead of 30 degree left turn.

Attributes
ACN	114128
Time
Date	198906
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : stj
State Reference	MO
Altitude	msl bound lower : 14000 msl bound upper : 14000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air taxi
Make Model Name	Small Transport, Low Wing, 2 Turboprop Eng
Flight Phase	cruise other
Route In Use	enroute : on vectors enroute airway : zkc
Flight Plan	IFR
Person 1
Affiliation	company : air taxi
Function	flight crew : captain oversight : pic
Qualification	pilot : commercial pilot : instrument
Experience	flight time last 90 days : 107 flight time total : 2050 flight time type : 1100
ASRS Report	114128
Person 2
Affiliation	company : air taxi
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	non adherence : clearance other spatial deviation
Independent Detector	other controllera
Resolutory Action	other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

I was in cruise when center told me to turn 30 degree to the left, center's transmission was scratchy. I thought he said 'turn 30 degree to the west' and that's what I did. Realizing they never, or I have never been given a heading using north, south, east or west I waited momentarily to confirm the heading change but could not get through because of radio congestion, so I elected to proceed to what I thought was my assigned heading. After reaching my new heading center called back and told me I should have had turned 30 degree to the left. I believe that if center's transmission had not been scratchy and if I would have been able to confirm the transmission sooner the problem would not have arose.

Original NASA ASRS Text

Title: PLT EXECUTES 30 DEGREE WEST TURN INSTEAD OF 30 DEGREE LEFT TURN.

Narrative: I WAS IN CRUISE WHEN CENTER TOLD ME TO TURN 30 DEG TO THE LEFT, CENTER'S XMISSION WAS SCRATCHY. I THOUGHT HE SAID 'TURN 30 DEG TO THE WEST' AND THAT'S WHAT I DID. REALIZING THEY NEVER, OR I HAVE NEVER BEEN GIVEN A HDG USING NORTH, SOUTH, EAST OR WEST I WAITED MOMENTARILY TO CONFIRM THE HDG CHANGE BUT COULD NOT GET THROUGH BECAUSE OF RADIO CONGESTION, SO I ELECTED TO PROCEED TO WHAT I THOUGHT WAS MY ASSIGNED HDG. AFTER REACHING MY NEW HDG CENTER CALLED BACK AND TOLD ME I SHOULD HAVE HAD TURNED 30 DEG TO THE LEFT. I BELIEVE THAT IF CENTER'S XMISSION HAD NOT BEEN SCRATCHY AND IF I WOULD HAVE BEEN ABLE TO CONFIRM THE XMISSION SOONER THE PROBLEM WOULD NOT HAVE AROSE.

Data retrieved from NASA's ASRS site as of August 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.