An MD82 on approach into las, nv, descends through assigned altitude.

Attributes
ACN	416401
Time
Date	199810
Day	Mon
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : lax airport : las
State Reference	NV
Altitude	msl bound lower : 5700 msl bound upper : 6000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : las
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	descent : approach descent other
Route In Use	approach : visual
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : flight engineer pilot : commercial pilot : atp
Experience	flight time last 90 days : 140 flight time total : 15000 flight time type : 5600
ASRS Report	416401
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : commercial pilot : instrument
Experience	flight time last 90 days : 255 flight time total : 6700 flight time type : 4600
ASRS Report	416530
Events
Anomaly	altitude deviation : overshoot non adherence : clearance
Independent Detector	other controllera
Resolutory Action	flight crew : returned to intended course or assigned course other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

While we were in visual conditions descending into las airport, approach control gave us a descent out of 8000 for 6000 ft. With the autoplt on, 6000 ft was set in the altitude selector of the autoplt, confirmed by both pilots by cockpit xref and a descent begun. We were on a left downwind to runway 25L. Approaching 6000 ft, approach control gave us traffic to follow at our 9 O'clock position, which we confirmed we had in sight and were then told to follow. We were in the base turn to follow the traffic when approach control told us to check altitude, as we were below 6000 ft. We looked up at the altitude selector and it was at 5000 ft and we were descending out of 5700 ft. We immediately climbed back to 6000 ft, at which time approach control cleared us for the visual approach to runway 25L. Neither one of us, the copilot nor myself, had set 5000 ft in the altitude selector. The major factor was getting distraction by following the 9 O'clock traffic and not watching the leveloff at 6000 ft with the autoplt on. The visual conditions also could have been a factor. To correct the situation, close attention to the leveloff should be adhered to -- even with the autoplt on.

Original NASA ASRS Text

Title: AN MD82 ON APCH INTO LAS, NV, DSNDS THROUGH ASSIGNED ALT.

Narrative: WHILE WE WERE IN VISUAL CONDITIONS DSNDING INTO LAS ARPT, APCH CTL GAVE US A DSCNT OUT OF 8000 FOR 6000 FT. WITH THE AUTOPLT ON, 6000 FT WAS SET IN THE ALT SELECTOR OF THE AUTOPLT, CONFIRMED BY BOTH PLTS BY COCKPIT XREF AND A DSCNT BEGUN. WE WERE ON A L DOWNWIND TO RWY 25L. APCHING 6000 FT, APCH CTL GAVE US TFC TO FOLLOW AT OUR 9 O'CLOCK POS, WHICH WE CONFIRMED WE HAD IN SIGHT AND WERE THEN TOLD TO FOLLOW. WE WERE IN THE BASE TURN TO FOLLOW THE TFC WHEN APCH CTL TOLD US TO CHK ALT, AS WE WERE BELOW 6000 FT. WE LOOKED UP AT THE ALT SELECTOR AND IT WAS AT 5000 FT AND WE WERE DSNDING OUT OF 5700 FT. WE IMMEDIATELY CLBED BACK TO 6000 FT, AT WHICH TIME APCH CTL CLRED US FOR THE VISUAL APCH TO RWY 25L. NEITHER ONE OF US, THE COPLT NOR MYSELF, HAD SET 5000 FT IN THE ALT SELECTOR. THE MAJOR FACTOR WAS GETTING DISTR BY FOLLOWING THE 9 O'CLOCK TFC AND NOT WATCHING THE LEVELOFF AT 6000 FT WITH THE AUTOPLT ON. THE VISUAL CONDITIONS ALSO COULD HAVE BEEN A FACTOR. TO CORRECT THE SIT, CLOSE ATTN TO THE LEVELOFF SHOULD BE ADHERED TO -- EVEN WITH THE AUTOPLT ON.

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.