Small aircraft pilot descends below radar minimum vectoring altitude on ILS approach. MVA.

Attributes
ACN	269814
Time
Date	199404
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : apa
State Reference	CO
Altitude	msl bound lower : 8000 msl bound upper : 9400
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zdv
Operator	general aviation : instructional
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Flight Phase	descent : approach descent other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : instrument pilot : private
Experience	flight time last 90 days : 15 flight time total : 350 flight time type : 30
ASRS Report	269814
Person 2
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Events
Anomaly	other anomaly other other spatial deviation
Independent Detector	other controllera other flight crewa
Resolutory Action	other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

I was on an IFR flight plan from cys direct apa. I requested a published ILS vectored approach to apa, which was granted. In setting and identifying the navigation radios for the ILS, I must have turned down the volume on the communication radio. By the time I noticed the 'silence' center was calling with concern in his voice because I was below his vectoring altitude, MVA was 9400 ft. I was at 8000. I was directed to turn north and climb to 9400 ft MSL, which I did. He then asked for flight conditions and was somewhat relieved when I told him vml. I then completed a vector and ILS approach to apa, broke off at lincoln avenue, entered the pattern and landed. I did not consciously turn down the volume so my hand must have bumped the volume control while adjusting the radio selection panel or getting the navigation for the ILS. The correction is to be more observant.

Original NASA ASRS Text

Title: SMA PLT DSNDS BELOW RADAR MINIMUM VECTORING ALT ON ILS APCH. MVA.

Narrative: I WAS ON AN IFR FLT PLAN FROM CYS DIRECT APA. I REQUESTED A PUBLISHED ILS VECTORED APCH TO APA, WHICH WAS GRANTED. IN SETTING AND IDENTIFYING THE NAV RADIOS FOR THE ILS, I MUST HAVE TURNED DOWN THE VOLUME ON THE COM RADIO. BY THE TIME I NOTICED THE 'SILENCE' CTR WAS CALLING WITH CONCERN IN HIS VOICE BECAUSE I WAS BELOW HIS VECTORING ALT, MVA WAS 9400 FT. I WAS AT 8000. I WAS DIRECTED TO TURN N AND CLB TO 9400 FT MSL, WHICH I DID. HE THEN ASKED FOR FLT CONDITIONS AND WAS SOMEWHAT RELIEVED WHEN I TOLD HIM VML. I THEN COMPLETED A VECTOR AND ILS APCH TO APA, BROKE OFF AT LINCOLN AVENUE, ENTERED THE PATTERN AND LANDED. I DID NOT CONSCIOUSLY TURN DOWN THE VOLUME SO MY HAND MUST HAVE BUMPED THE VOLUME CTL WHILE ADJUSTING THE RADIO SELECTION PANEL OR GETTING THE NAV FOR THE ILS. THE CORRECTION IS TO BE MORE OBSERVANT.

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.