Air carrier flight crew goes approximately 400 ft below assigned altitude on approach at lhr.

Attributes
ACN	433853
Time
Date	199904
Day	Sun
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : egll.airport
State Reference	FO
Altitude	msl bound lower : 3600 msl bound upper : 4000
Environment
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : egtt.tracon
Operator	common carrier : air carrier
Make Model Name	B767-300 and 300 ER
Operating Under FAR Part	Part 121
Navigation In Use	ils localizer & glide slope : 27r other
Flight Phase	descent : intermediate altitude descent : approach
Route In Use	approach : instrument precision arrival : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	433853
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
ASRS Report	433053
Events
Anomaly	altitude deviation : overshoot altitude deviation : excursion from assigned altitude non adherence : far non adherence : company policies non adherence : clearance non adherence : published procedure other spatial deviation
Independent Detector	other flight crewa other flight crewb other other : person 3
Resolutory Action	flight crew : returned to original clearance flight crew : overcame equipment problem
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

All night flight, late arrival in terminal area with 30 min hold starting at FL290. Descended in holding 1000 ft increments to FL080. Transition altitude was 6000 ft. Cleared for unexpected short turn to final and controller gave altimeter as 'niner niner five.' during descending turn to final while looking for traffic 29.95 was set in inches window instead of 995 in millibars window. Leveled off below IAF altitude of 4000 ft before resetting 995 millibars in correct window. Intercepted GS and made normal approach after correcting altimeter.

Original NASA ASRS Text

Title: ACR FLC GOES APPROX 400 FT BELOW ASSIGNED ALT ON APCH AT LHR.

Narrative: ALL NIGHT FLT, LATE ARR IN TERMINAL AREA WITH 30 MIN HOLD STARTING AT FL290. DSNDED IN HOLDING 1000 FT INCREMENTS TO FL080. TRANSITION ALT WAS 6000 FT. CLRED FOR UNEXPECTED SHORT TURN TO FINAL AND CTLR GAVE ALTIMETER AS 'NINER NINER FIVE.' DURING DSNDING TURN TO FINAL WHILE LOOKING FOR TFC 29.95 WAS SET IN INCHES WINDOW INSTEAD OF 995 IN MILLIBARS WINDOW. LEVELED OFF BELOW IAF ALT OF 4000 FT BEFORE RESETTING 995 MILLIBARS IN CORRECT WINDOW. INTERCEPTED GS AND MADE NORMAL APCH AFTER CORRECTING ALTIMETER.

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.