Air carrier crew exceeds speed restriction and descends below assigned altitude.

Attributes
ACN	156622
Time
Date	199009
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : atl
State Reference	GA
Altitude	msl bound lower : 11500 msl bound upper : 12000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	descent other
Route In Use	arrival other enroute airway : ztl
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : flight engineer
Experience	flight time last 90 days : 240 flight time total : 10000 flight time type : 240
ASRS Report	156622
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 130 flight time total : 2700 flight time type : 130
ASRS Report	156625
Events
Anomaly	altitude deviation : overshoot non adherence : clearance other anomaly
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:

During descent into atlanta, we were operating under an ATC clearance to cross 40 mi out of atl at 12000'/250 KTS. Aircraft was being operated with autoplt 'on', vertical speed mode, with the autothrottles 'off'. As aircraft altitude approached 10000', both pilots' attention was directed outside of the cockpit due to a small WX buildup in our 12 O'clock position. We made a very short deviation to avoid the buildup, and just then I noticed our altitude at 11700' and descending. I notified the copilot and he immediately disconnected the autoplt and manually flew the aircraft back to 12000' (altitude bottomed at 11500'). This aircraft had successfully 'captured' numerous altitudes during climb out and earlier stages of the descent, so we were inclined to believe it would continue to do so. This belief, along with the distraction caused by a WX buildup, caused both pilots to miss the fact that the autoplt had not 'captured' the selected altitude. Factors which may have affected pilot performance include: captain was being relieved in atlanta due to the onset of common cold symptoms (coughing, sneezing, etc). Copilot was also being relieved in atlanta, as his wife was 'in labor' with their first child.

Original NASA ASRS Text

Title: ACR CREW EXCEEDS SPEED RESTRICTION AND DESCENDS BELOW ASSIGNED ALT.

Narrative: DURING DSNT INTO ATLANTA, WE WERE OPERATING UNDER AN ATC CLRNC TO CROSS 40 MI OUT OF ATL AT 12000'/250 KTS. ACFT WAS BEING OPERATED WITH AUTOPLT 'ON', VERT SPD MODE, WITH THE AUTOTHROTTLES 'OFF'. AS ACFT ALT APCHED 10000', BOTH PLTS' ATTN WAS DIRECTED OUTSIDE OF THE COCKPIT DUE TO A SMALL WX BUILDUP IN OUR 12 O'CLOCK POS. WE MADE A VERY SHORT DEV TO AVOID THE BUILDUP, AND JUST THEN I NOTICED OUR ALT AT 11700' AND DSNDING. I NOTIFIED THE COPLT AND HE IMMEDIATELY DISCONNECTED THE AUTOPLT AND MANUALLY FLEW THE ACFT BACK TO 12000' (ALT BOTTOMED AT 11500'). THIS ACFT HAD SUCCESSFULLY 'CAPTURED' NUMEROUS ALTS DURING CLBOUT AND EARLIER STAGES OF THE DSNT, SO WE WERE INCLINED TO BELIEVE IT WOULD CONTINUE TO DO SO. THIS BELIEF, ALONG WITH THE DISTR CAUSED BY A WX BUILDUP, CAUSED BOTH PLTS TO MISS THE FACT THAT THE AUTOPLT HAD NOT 'CAPTURED' THE SELECTED ALT. FACTORS WHICH MAY HAVE AFFECTED PLT PERFORMANCE INCLUDE: CAPT WAS BEING RELIEVED IN ATLANTA DUE TO THE ONSET OF COMMON COLD SYMPTOMS (COUGHING, SNEEZING, ETC). COPLT WAS ALSO BEING RELIEVED IN ATLANTA, AS HIS WIFE WAS 'IN LABOR' WITH THEIR FIRST CHILD.

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.