C172 practicing IFR approachs into baf varies from ATC assigned altitude and heading.

Attributes
ACN	578577
Time
Date	200304
Day	Thu
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : baf.airport
State Reference	MA
Altitude	msl single value : 3000
Environment
Flight Conditions	Marginal
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : y90.tracon
Operator	general aviation : personal
Make Model Name	Skyhawk 172/Cutlass 172
Operating Under FAR Part	Part 91
Navigation In Use	ils localizer & glide slope : 20 other vortac
Flight Phase	descent : approach
Route In Use	approach : instrument non precision approach : instrument precision arrival : 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 : 6.7 flight time total : 510 flight time type : 10.3
ASRS Report	578577
Person 2
Affiliation	government : faa
Function	controller : approach
Events
Anomaly	altitude deviation : excursion from assigned altitude inflight encounter : weather non adherence : clearance other spatial deviation
Independent Detector	other flight crewa
Resolutory Action	flight crew : returned to original clearance
Supplementary
Problem Areas	Flight Crew Human Performance Weather
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

On being vectored for the ILS runway 20 at baf by bradley approach control on a practice approach in IMC at my assigned altitude of 3000 ft, I received a navigation flag on the localizer/GS readout instrument. I informed bradley of the flag, and asked to have time to figure out the problem. Bradley told me to remain at 3000 ft and gave me a heading of 110 degrees. For the next 5 mins I tried to figure out why I was getting flags on both navigation and GS. I was unable to determine the source of the difficulty, so I switched to the #2 navigation system and requested the VOR approach to baf runway 20. Bradley vectored me around, and then cleared me for the approach, which I executed and landed. During the time I was investigating the problem, both my heading and altitude varied considerably. I was more than 300 ft above and below the assigned 3000 ft altitude, and my heading varied substantially. I was in solid IMC the whole time. While the controller was patient and helpful, and I eventually (if somewhat erratically) worked my way back to the airport using the VOR approach, I am reporting the unintentional deviation from ATC assignments. I realize now that I should have xferred sooner to the navigation #2 system and concentrated more on stabilizing the approach. Although I am IFR current, I have scheduled time with an instructor to improve my proficiency in actual IMC.

Original NASA ASRS Text

Title: C172 PRACTICING IFR APCHS INTO BAF VARIES FROM ATC ASSIGNED ALT AND HEADING.

Narrative: ON BEING VECTORED FOR THE ILS RWY 20 AT BAF BY BRADLEY APCH CTL ON A PRACTICE APCH IN IMC AT MY ASSIGNED ALT OF 3000 FT, I RECEIVED A NAV FLAG ON THE LOC/GS READOUT INST. I INFORMED BRADLEY OF THE FLAG, AND ASKED TO HAVE TIME TO FIGURE OUT THE PROB. BRADLEY TOLD ME TO REMAIN AT 3000 FT AND GAVE ME A HEADING OF 110 DEGS. FOR THE NEXT 5 MINS I TRIED TO FIGURE OUT WHY I WAS GETTING FLAGS ON BOTH NAV AND GS. I WAS UNABLE TO DETERMINE THE SOURCE OF THE DIFFICULTY, SO I SWITCHED TO THE #2 NAV SYS AND REQUESTED THE VOR APCH TO BAF RWY 20. BRADLEY VECTORED ME AROUND, AND THEN CLRED ME FOR THE APCH, WHICH I EXECUTED AND LANDED. DURING THE TIME I WAS INVESTIGATING THE PROB, BOTH MY HEADING AND ALT VARIED CONSIDERABLY. I WAS MORE THAN 300 FT ABOVE AND BELOW THE ASSIGNED 3000 FT ALT, AND MY HEADING VARIED SUBSTANTIALLY. I WAS IN SOLID IMC THE WHOLE TIME. WHILE THE CTLR WAS PATIENT AND HELPFUL, AND I EVENTUALLY (IF SOMEWHAT ERRATICALLY) WORKED MY WAY BACK TO THE ARPT USING THE VOR APCH, I AM RPTING THE UNINTENTIONAL DEV FROM ATC ASSIGNMENTS. I REALIZE NOW THAT I SHOULD HAVE XFERRED SOONER TO THE NAV #2 SYS AND CONCENTRATED MORE ON STABILIZING THE APCH. ALTHOUGH I AM IFR CURRENT, I HAVE SCHEDULED TIME WITH AN INSTRUCTOR TO IMPROVE MY PROFICIENCY IN ACTUAL IMC.

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.