B767-200 crew went below the cleared altitude and below the GS on approach to runway 9R at ord.

Attributes
ACN	583617
Time
Date	200306
Day	Tue
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : ord.airport
State Reference	IL
Altitude	msl bound lower : 1705 msl bound upper : 2205
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	tower : ord.tower
Operator	common carrier : air carrier
Make Model Name	B767-200
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	descent : approach
Route In Use	approach : visual
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 471 flight time total : 4261 flight time type : 765
ASRS Report	583617
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : published procedure non adherence : far non adherence : clearance non adherence : company policies
Independent Detector	other flight crewa
Resolutory Action	flight crew : returned to assigned altitude
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance

Narrative:

We were on downwind to ord runway 9R at 4000 ft, approximately 15 mi from the end of the runway. Tower asked if we had field in sight, captain said he did, I did not. After calling 'field in sight,' tower cleared us for the visual approach and told us to maintain 4000 ft until on final for noise abatement. The captain, as PF, started a descending turn. I mentioned the 4000 ft until on final, and he said that since he was turning to final he could descend. He had set 1500 ft in the autoplt altitude window, and stated he was high and needed to get down. This did not seem right to me. We were 7 mi from the FAF. I quickly crosschecked the FAF altitude with my approach plate and saw it was 2205 ft. I told the captain that we were 7 mi from FAF, and the altitude at FAF was 2205 ft. He noted his mistake and began to fix it. We went approximately 500 ft below the FAF altitude at about 5 mi out from FAF. After fixing mistake, flight proceeded uneventfully. Later, captain said he had his electronic map display on the wrong scale making him feel closer to FAF, and thus high.

Original NASA ASRS Text

Title: B767-200 CREW WENT BELOW THE CLRED ALT AND BELOW THE GS ON APCH TO RWY 9R AT ORD.

Narrative: WE WERE ON DOWNWIND TO ORD RWY 9R AT 4000 FT, APPROX 15 MI FROM THE END OF THE RWY. TWR ASKED IF WE HAD FIELD IN SIGHT, CAPT SAID HE DID, I DID NOT. AFTER CALLING 'FIELD IN SIGHT,' TWR CLRED US FOR THE VISUAL APCH AND TOLD US TO MAINTAIN 4000 FT UNTIL ON FINAL FOR NOISE ABATEMENT. THE CAPT, AS PF, STARTED A DSNDING TURN. I MENTIONED THE 4000 FT UNTIL ON FINAL, AND HE SAID THAT SINCE HE WAS TURNING TO FINAL HE COULD DSND. HE HAD SET 1500 FT IN THE AUTOPLT ALT WINDOW, AND STATED HE WAS HIGH AND NEEDED TO GET DOWN. THIS DID NOT SEEM RIGHT TO ME. WE WERE 7 MI FROM THE FAF. I QUICKLY XCHKED THE FAF ALT WITH MY APCH PLATE AND SAW IT WAS 2205 FT. I TOLD THE CAPT THAT WE WERE 7 MI FROM FAF, AND THE ALT AT FAF WAS 2205 FT. HE NOTED HIS MISTAKE AND BEGAN TO FIX IT. WE WENT APPROX 500 FT BELOW THE FAF ALT AT ABOUT 5 MI OUT FROM FAF. AFTER FIXING MISTAKE, FLT PROCEEDED UNEVENTFULLY. LATER, CAPT SAID HE HAD HIS ELECTRONIC MAP DISPLAY ON THE WRONG SCALE MAKING HIM FEEL CLOSER TO FAF, AND THUS HIGH.

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.