MD80 captain submits a suggestion to improve the MD80 autoflt system.

Attributes
ACN	422352
Time
Date	199812
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : abi
State Reference	TX
Altitude	msl bound lower : 35000 msl bound upper : 35000
Environment
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	MD-80 Super 80
Operating Under FAR Part	Part 121
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
ASRS Report	422352
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial
Events
Anomaly	other anomaly other
Independent Detector	other flight crewa
Resolutory Action	other
Consequence	Other
Supplementary
Air Traffic Incident	other

Narrative:

It appears the automatic FMS is programmed to use up to 30 degrees of bank when making coupled course changes. This is ok at lower altitudes, but at high cruise altitude this is not a good idea. In the future, I will select heading mode, change course, then re-engage automatic FMS for large heading changes. Too bad these units cannot be programmed to prevent this.

Original NASA ASRS Text

Title: MD80 CAPT SUBMITS A SUGGESTION TO IMPROVE THE MD80 AUTOFLT SYS.

Narrative: IT APPEARS THE AUTO FMS IS PROGRAMMED TO USE UP TO 30 DEGS OF BANK WHEN MAKING COUPLED COURSE CHANGES. THIS IS OK AT LOWER ALTS, BUT AT HIGH CRUISE ALT THIS IS NOT A GOOD IDEA. IN THE FUTURE, I WILL SELECT HDG MODE, CHANGE COURSE, THEN RE-ENGAGE AUTO FMS FOR LARGE HDG CHANGES. TOO BAD THESE UNITS CANNOT BE PROGRAMMED TO PREVENT THIS.

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.