B757 crew deviates from assigned altitude due to turbulence in den airspace.

Attributes
ACN	406230
Time
Date	199806
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : den
State Reference	CO
Altitude	msl bound lower : 12000 msl bound upper : 12400
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : den
Operator	common carrier : air carrier
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	climbout : intermediate altitude
Route In Use	departure sid : sid
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 180 flight time total : 9500 flight time type : 300
ASRS Report	406230
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : overshoot non adherence : clearance other anomaly other 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

Narrative:

First officer was hand flying the aircraft on a SID. During intermediate leveloff in moderate turbulence, the aircraft overshot, 12000 ft and leveled at approximately 12090 ft. As the turbulence increased the aircraft continued to accelerate toward planned cruise speed of 310 KIAS. The aircraft continued a climb in moderate turbulence with a level attitude while accelerating. At approximately 150 ft above assigned altitude the captain pointed this out. I decreased the pitch attitude an additional 2-3 degrees below level but the aircraft continued to climb and accelerate. The aircraft altitude warning went off and I increased nose down attitude another 2 degrees. Level flight was achieved but the aircraft would not descend until autothrottle override. Upon override the aircraft returned to assigned altitude of 12000 ft. Total time of deviation was approximately 10 seconds.

Original NASA ASRS Text

Title: B757 CREW DEVIATES FROM ASSIGNED ALT DUE TO TURB IN DEN AIRSPACE.

Narrative: FO WAS HAND FLYING THE ACFT ON A SID. DURING INTERMEDIATE LEVELOFF IN MODERATE TURB, THE ACFT OVERSHOT, 12000 FT AND LEVELED AT APPROX 12090 FT. AS THE TURB INCREASED THE ACFT CONTINUED TO ACCELERATE TOWARD PLANNED CRUISE SPD OF 310 KIAS. THE ACFT CONTINUED A CLB IN MODERATE TURB WITH A LEVEL ATTITUDE WHILE ACCELERATING. AT APPROX 150 FT ABOVE ASSIGNED ALT THE CAPT POINTED THIS OUT. I DECREASED THE PITCH ATTITUDE AN ADDITIONAL 2-3 DEGS BELOW LEVEL BUT THE ACFT CONTINUED TO CLB AND ACCELERATE. THE ACFT ALT WARNING WENT OFF AND I INCREASED NOSE DOWN ATTITUDE ANOTHER 2 DEGS. LEVEL FLT WAS ACHIEVED BUT THE ACFT WOULD NOT DSND UNTIL AUTOTHROTTLE OVERRIDE. UPON OVERRIDE THE ACFT RETURNED TO ASSIGNED ALT OF 12000 FT. TOTAL TIME OF DEV WAS APPROX 10 SECONDS.

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.