PA24 pilot descended below the minimum altitude listed on the approach chart at dwh.

Attributes
ACN	485820
Time
Date	200009
Day	Tue
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : dwh.airport
State Reference	TX
Altitude	msl bound lower : 1500 msl bound upper : 1800
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	tower : dwh.tower
Operator	general aviation : personal
Make Model Name	PA-24 Comanche
Operating Under FAR Part	Part 91
Navigation In Use	ils localizer only : 17r
Flight Phase	descent : approach
Route In Use	approach : visual
Flight Plan	IFR
Person 1
Affiliation	other
Function	flight crew : single pilot
Qualification	pilot : instrument pilot : commercial
Experience	flight time last 90 days : 45 flight time total : 780 flight time type : 600
ASRS Report	485820
Person 2
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : published procedure non adherence : far non adherence : clearance other anomaly other
Independent Detector	atc equipment : msaw other controllera other controllerb
Resolutory Action	controller : issued alert
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:

On arrival in the houston terminal area, approach asked if I wanted a direct visual, or the approach into dwh. I replied that I would like to 'follow the localizer in.' approach then vectored and cleared me for the dwh localizer runway 17R approach. The minimum altitude on this approach is 1800 ft until the FAF at 6 DME. WX was cavu. I reported visual on dwh at about 12 DME upon joining the localizer. Approach almost immediately handed me to dwh tower. I contacted dwh tower and reported 'on the localizer.' dwh tower immediately cleared me to land. At this point I was still about 8-10 DME out. Having dwh visual under tower control in class east, I was in position for a normal approach and landing. I therefore began a gentle descent to 1500 ft (which is the normal local VFR approach altitude for dwh runway 17R). My position, being appropriate for a normal approach and landing, coupled with cavu VMC and proximity to the field did not seem to mandate completion of the formal approach procedure to the FAF. Approach called the tower and discussed my descent below 1800 ft prior to the 6 DME FAF for the localizer runway 17R approach. I replied to the effect that 'I guess I had taken some liberty because of the conditions.' my understanding is that dwh tower indicated they had no issue, but that approach wanted to confirm I, in fact, knew the correct altitude was 1800 ft to the FAF and that I should have maintained that altitude. I attribute my (apparent) confusion regarding the requirement to hold altitude to the extremely early handoff to the dwh tower while in class east space coupled with the cavu conditions providing the appropriate 'in position for a normal landing' even though I had not passed the FAF. It might have been appropriate for me to cancel IFR upon handoff to the tower, but in the context of the approach and landing scenario, it seemed redundant to the situation. In the future, I will ensure complete formality prior to any deviation.

Original NASA ASRS Text

Title: PA24 PLT DSNDED BELOW THE MINIMUM ALT LISTED ON THE APCH CHART AT DWH.

Narrative: ON ARR IN THE HOUSTON TERMINAL AREA, APCH ASKED IF I WANTED A DIRECT VISUAL, OR THE APCH INTO DWH. I REPLIED THAT I WOULD LIKE TO 'FOLLOW THE LOC IN.' APCH THEN VECTORED AND CLRED ME FOR THE DWH LOC RWY 17R APCH. THE MINIMUM ALT ON THIS APCH IS 1800 FT UNTIL THE FAF AT 6 DME. WX WAS CAVU. I RPTED VISUAL ON DWH AT ABOUT 12 DME UPON JOINING THE LOC. APCH ALMOST IMMEDIATELY HANDED ME TO DWH TWR. I CONTACTED DWH TWR AND RPTED 'ON THE LOC.' DWH TWR IMMEDIATELY CLRED ME TO LAND. AT THIS POINT I WAS STILL ABOUT 8-10 DME OUT. HAVING DWH VISUAL UNDER TWR CTL IN CLASS E, I WAS IN POS FOR A NORMAL APCH AND LNDG. I THEREFORE BEGAN A GENTLE DSCNT TO 1500 FT (WHICH IS THE NORMAL LCL VFR APCH ALT FOR DWH RWY 17R). MY POS, BEING APPROPRIATE FOR A NORMAL APCH AND LNDG, COUPLED WITH CAVU VMC AND PROX TO THE FIELD DID NOT SEEM TO MANDATE COMPLETION OF THE FORMAL APCH PROC TO THE FAF. APCH CALLED THE TWR AND DISCUSSED MY DSCNT BELOW 1800 FT PRIOR TO THE 6 DME FAF FOR THE LOC RWY 17R APCH. I REPLIED TO THE EFFECT THAT 'I GUESS I HAD TAKEN SOME LIBERTY BECAUSE OF THE CONDITIONS.' MY UNDERSTANDING IS THAT DWH TWR INDICATED THEY HAD NO ISSUE, BUT THAT APCH WANTED TO CONFIRM I, IN FACT, KNEW THE CORRECT ALT WAS 1800 FT TO THE FAF AND THAT I SHOULD HAVE MAINTAINED THAT ALT. I ATTRIBUTE MY (APPARENT) CONFUSION REGARDING THE REQUIREMENT TO HOLD ALT TO THE EXTREMELY EARLY HDOF TO THE DWH TWR WHILE IN CLASS E SPACE COUPLED WITH THE CAVU CONDITIONS PROVIDING THE APPROPRIATE 'IN POS FOR A NORMAL LNDG' EVEN THOUGH I HAD NOT PASSED THE FAF. IT MIGHT HAVE BEEN APPROPRIATE FOR ME TO CANCEL IFR UPON HDOF TO THE TWR, BUT IN THE CONTEXT OF THE APCH AND LNDG SCENARIO, IT SEEMED REDUNDANT TO THE SIT. IN THE FUTURE, I WILL ENSURE COMPLETE FORMALITY PRIOR TO ANY DEV.

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.