Air carrier PIC uses moderate chop as reason for altitude excursion off course.

Attributes
ACN	145514
Time
Date	199005
Day	Mon
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : pmd
State Reference	CA
Altitude	msl bound lower : 23500 msl bound upper : 24000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zla
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	cruise other descent other
Route In Use	arrival other arrival star : star
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : cfi
Experience	flight time last 90 days : 30 flight time total : 6500 flight time type : 2500
ASRS Report	145514
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : excursion from assigned altitude inflight encounter other non adherence : clearance other spatial deviation
Independent Detector	other controllera other flight crewa
Resolutory Action	controller : issued new clearance flight crew : exited adverse environment
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Operating from dfw to sba, ZLA advisory of 'light chop' in descent. Cleared pmd direct fillmore and the qwang arrival to sba. Leaving FL280 began to pick up moderate chop. Upon leveling at FL240 we were in continuous 'moderate turbulence.' several requests to ZLA for lower altitudes were made. Requests refused. The captain then turned 90 degrees off arwy and began descent. ZLA was advised of this and we were given FL210, which was maintained. Very bad and dangerous ride at FL240. It should have been used only as a transition altitude and traffic should have been expedited through this altitude.

Original NASA ASRS Text

Title: ACR PIC USES MODERATE CHOP AS REASON FOR ALT EXCURSION OFF COURSE.

Narrative: OPERATING FROM DFW TO SBA, ZLA ADVISORY OF 'LIGHT CHOP' IN DSNT. CLRED PMD DIRECT FILLMORE AND THE QWANG ARR TO SBA. LEAVING FL280 BEGAN TO PICK UP MODERATE CHOP. UPON LEVELING AT FL240 WE WERE IN CONTINUOUS 'MODERATE TURB.' SEVERAL REQUESTS TO ZLA FOR LOWER ALTS WERE MADE. REQUESTS REFUSED. THE CAPT THEN TURNED 90 DEGS OFF ARWY AND BEGAN DSNT. ZLA WAS ADVISED OF THIS AND WE WERE GIVEN FL210, WHICH WAS MAINTAINED. VERY BAD AND DANGEROUS RIDE AT FL240. IT SHOULD HAVE BEEN USED ONLY AS A TRANSITION ALT AND TFC SHOULD HAVE BEEN EXPEDITED THROUGH THIS ALT.

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.