Descended 500' too far while still outside the marker on an ILS approach.

Attributes
ACN	176472
Time
Date	199104
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : jax
State Reference	FL
Altitude	msl bound lower : 1100 msl bound upper : 1600
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : jax
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	descent : approach descent other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 130 flight time total : 18000 flight time type : 1500
ASRS Report	176472
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	altitude deviation : crossing restriction not met altitude deviation : excursion from assigned altitude non adherence : published procedure non adherence : clearance
Independent Detector	other flight crewa
Resolutory Action	none taken : anomaly accepted
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

We were descending to 2000' MSL given an intercept heading to intercept localizer for runway 25 at jax. We were told to maintain 2000' until on the localizer, which we did. We had been on a downwind leg and had seen the airport as we passed by. When we were cleared to intercept the localizer, approach control said we were 5 mi from marker (pekon) but trail apparently didn't register with me because in my mind I thought we were inside the marker because as soon as I intercepted the localizer I left 2000' and descended to 1100' while looking for the field. As I was starting to level off at 1100' because I spotted the runway, the first officer said 'have we passed the marker yet.' it was at that point that I realized we hadn't and that we should have been at 1600' since we were on a localizer only approach, even though it was VMC. I believe this episode was caused primarily by the fact that I was preoccupied, plus the first officer was trying to pickup the runway and we were all probably a little too lax because the WX was VMC. Something else that might have prevented this episode would be if jax had a DME.

Original NASA ASRS Text

Title: DESCENDED 500' TOO FAR WHILE STILL OUTSIDE THE MARKER ON AN ILS APCH.

Narrative: WE WERE DSNDING TO 2000' MSL GIVEN AN INTERCEPT HDG TO INTERCEPT LOC FOR RWY 25 AT JAX. WE WERE TOLD TO MAINTAIN 2000' UNTIL ON THE LOC, WHICH WE DID. WE HAD BEEN ON A DOWNWIND LEG AND HAD SEEN THE ARPT AS WE PASSED BY. WHEN WE WERE CLRED TO INTERCEPT THE LOC, APCH CTL SAID WE WERE 5 MI FROM MARKER (PEKON) BUT TRAIL APPARENTLY DIDN'T REGISTER WITH ME BECAUSE IN MY MIND I THOUGHT WE WERE INSIDE THE MARKER BECAUSE AS SOON AS I INTERCEPTED THE LOC I LEFT 2000' AND DSNDED TO 1100' WHILE LOOKING FOR THE FIELD. AS I WAS STARTING TO LEVEL OFF AT 1100' BECAUSE I SPOTTED THE RWY, THE F/O SAID 'HAVE WE PASSED THE MARKER YET.' IT WAS AT THAT POINT THAT I REALIZED WE HADN'T AND THAT WE SHOULD HAVE BEEN AT 1600' SINCE WE WERE ON A LOC ONLY APCH, EVEN THOUGH IT WAS VMC. I BELIEVE THIS EPISODE WAS CAUSED PRIMARILY BY THE FACT THAT I WAS PREOCCUPIED, PLUS THE F/O WAS TRYING TO PICKUP THE RWY AND WE WERE ALL PROBABLY A LITTLE TOO LAX BECAUSE THE WX WAS VMC. SOMETHING ELSE THAT MIGHT HAVE PREVENTED THIS EPISODE WOULD BE IF JAX HAD A DME.

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.