A DC9 crew, on descent near lex, overshot assigned altitude.

Attributes
ACN	532629
Time
Date	200112
Day	Sat
Local Time Of Day	0001 To 0600
Place
Locale Reference	navaid : hyk.vortac
State Reference	KY
Altitude	msl bound lower : 28600 msl bound upper : 29000
Environment
Flight Conditions	VMC
Weather Elements	Turbulence
Light	Night
Aircraft 1
Controlling Facilities	artcc : zid.artcc
Operator	common carrier : air carrier
Make Model Name	DC-9 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	other vortac
Flight Phase	descent : intermediate altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 75 flight time total : 9500 flight time type : 2000
ASRS Report	532629
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	altitude deviation : overshoot non adherence : company policies non adherence : published procedure non adherence : clearance
Independent Detector	other controllera other flight crewa other flight crewb
Resolutory Action	flight crew : returned to assigned altitude flight crew : overrode automation
Consequence	faa : reviewed incident with flight crew
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Descent out of FL330 to cross 30 mi southwest of hyk at FL290. At approximately FL295, ATC issued a new route clearance. Captain flying (on autoplt) as first officer programmed new route into RNAV. I became preoccupied with watching first officer to see if it was programmed correctly. Altitude deviation chime occurred at FL287, autoplt immediately disconnected and climb initiated back to FL290. Aircraft had descended to a minimum altitude of FL286. Level at FL290, ATC inquired about our altitude. We responded we were level at FL290. I don't believe any conflict existed for 2 reasons. ATC controller sounded very calm and disinterested and approximately 15 seconds later he issued descent clearance to FL280. The most influential human factor would be fatigue, as this was after XA00 and no matter how much rest you had the day before, it is very tiring flying the back side of the clock. Also contributing is that the company only has about 12 EFIS equipped aircraft out of fleet of xo DC9's. I only fly EFIS aircraft approximately 1-2 times per yr and all displays and controls are very different requiring much more attention to ensure right buttons are pushed. Aircraft fleet should be more standard!

Original NASA ASRS Text

Title: A DC9 CREW, ON DSCNT NEAR LEX, OVERSHOT ASSIGNED ALT.

Narrative: DSCNT OUT OF FL330 TO CROSS 30 MI SW OF HYK AT FL290. AT APPROX FL295, ATC ISSUED A NEW RTE CLRNC. CAPT FLYING (ON AUTOPLT) AS FO PROGRAMMED NEW RTE INTO RNAV. I BECAME PREOCCUPIED WITH WATCHING FO TO SEE IF IT WAS PROGRAMMED CORRECTLY. ALTDEV CHIME OCCURRED AT FL287, AUTOPLT IMMEDIATELY DISCONNECTED AND CLB INITIATED BACK TO FL290. ACFT HAD DSNDED TO A MINIMUM ALT OF FL286. LEVEL AT FL290, ATC INQUIRED ABOUT OUR ALT. WE RESPONDED WE WERE LEVEL AT FL290. I DON'T BELIEVE ANY CONFLICT EXISTED FOR 2 REASONS. ATC CTLR SOUNDED VERY CALM AND DISINTERESTED AND APPROX 15 SECONDS LATER HE ISSUED DSCNT CLRNC TO FL280. THE MOST INFLUENTIAL HUMAN FACTOR WOULD BE FATIGUE, AS THIS WAS AFTER XA00 AND NO MATTER HOW MUCH REST YOU HAD THE DAY BEFORE, IT IS VERY TIRING FLYING THE BACK SIDE OF THE CLOCK. ALSO CONTRIBUTING IS THAT THE COMPANY ONLY HAS ABOUT 12 EFIS EQUIPPED ACFT OUT OF FLEET OF XO DC9'S. I ONLY FLY EFIS ACFT APPROX 1-2 TIMES PER YR AND ALL DISPLAYS AND CTLS ARE VERY DIFFERENT REQUIRING MUCH MORE ATTN TO ENSURE RIGHT BUTTONS ARE PUSHED. ACFT FLEET SHOULD BE MORE STANDARD!

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.