Frequent changes in clearance altitude in descent creates an altitude deviation during level off.

Attributes
ACN	123921
Time
Date	198909
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : gdm
State Reference	MA
Altitude	msl bound lower : 26000 msl bound upper : 27000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zbw
Operator	common carrier : air carrier
Make Model Name	Widebody, Low Wing, 2 Turbojet Eng
Navigation In Use	Other
Flight Phase	cruise other descent other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time total : 16000
ASRS Report	123921
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	altitude deviation : overshoot non adherence : clearance other anomaly other
Independent Detector	other flight crewa
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 other

Narrative:

Controller changed final descent altitude 3 times, always raising it. Final altitude was FL270. Altitude previous to this was FL260. We did not notice but flight director had already captured 260 and did not reset when 270 was set into AFDS panel. We descended to FL266 and climbed immediately to FL270. Would be helpful to not have so many altitude reassignments in rapid succession. The ATC system could use more and better controllers. More automation. Too many frequency changes in too short a distance.

Original NASA ASRS Text

Title: FREQUENT CHANGES IN CLRNC ALT IN DESCENT CREATES AN ALT DEVIATION DURING LEVEL OFF.

Narrative: CTLR CHANGED FINAL DSCNT ALT 3 TIMES, ALWAYS RAISING IT. FINAL ALT WAS FL270. ALT PREVIOUS TO THIS WAS FL260. WE DID NOT NOTICE BUT FLT DIRECTOR HAD ALREADY CAPTURED 260 AND DID NOT RESET WHEN 270 WAS SET INTO AFDS PANEL. WE DESCENDED TO FL266 AND CLIMBED IMMEDIATELY TO FL270. WOULD BE HELPFUL TO NOT HAVE SO MANY ALT REASSIGNMENTS IN RAPID SUCCESSION. THE ATC SYSTEM COULD USE MORE AND BETTER CTLRS. MORE AUTOMATION. TOO MANY FREQ CHANGES IN TOO SHORT A DISTANCE.

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.