Small aircraft strayed from the biltmore class B transition corridor when his HSI precessed. ATC str...

Attributes
ACN	362200
Time
Date	199703
Day	Sat
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : phx
State Reference	AZ
Altitude	msl bound lower : 4000 msl bound upper : 4000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : phx
Operator	general aviation : personal
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Flight Phase	cruise other
Flight Plan	None
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : commercial pilot : instrument
Experience	flight time total : 5000
ASRS Report	362200
Person 2
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Events
Anomaly	aircraft equipment problem : less severe other anomaly other other spatial deviation
Independent Detector	other controllera
Resolutory Action	other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

I was sbound through the biltmore transition corridor on a class B clearance at 4000 ft, WX clear, as I got closer to phx airport and the airport area started to become blocked under my nose, I used my HSI for heading reference while watching for traffic. When I saw a scheduled carrier climbing out close to the ground (2500 ft below?) just to the left of my cowling, I maneuvered for a better surface look and turned right to pass over the center of the airport as required. As I started to turn, the controller said I was headed wrong and vectored me to 210 degrees and then back south. He never said I had left the corridor, whose boundaries are not defined. The cause of the incorrect heading became apparent on landing 10-15 mins later when I saw on final that my HSI was reading 35-40 degrees off the runway heading/numbers. Checking the HSI after landing, it was properly set, not in free slave but reading erroneously.

Original NASA ASRS Text

Title: SMA STRAYED FROM THE BILTMORE CLASS B TRANSITION CORRIDOR WHEN HIS HSI PRECESSED. ATC STRAIGHTENED HIM OUT.

Narrative: I WAS SBOUND THROUGH THE BILTMORE TRANSITION CORRIDOR ON A CLASS B CLRNC AT 4000 FT, WX CLR, AS I GOT CLOSER TO PHX ARPT AND THE ARPT AREA STARTED TO BECOME BLOCKED UNDER MY NOSE, I USED MY HSI FOR HDG REF WHILE WATCHING FOR TFC. WHEN I SAW A SCHEDULED CARRIER CLBING OUT CLOSE TO THE GND (2500 FT BELOW?) JUST TO THE L OF MY COWLING, I MANEUVERED FOR A BETTER SURFACE LOOK AND TURNED R TO PASS OVER THE CTR OF THE ARPT AS REQUIRED. AS I STARTED TO TURN, THE CTLR SAID I WAS HEADED WRONG AND VECTORED ME TO 210 DEGS AND THEN BACK S. HE NEVER SAID I HAD LEFT THE CORRIDOR, WHOSE BOUNDARIES ARE NOT DEFINED. THE CAUSE OF THE INCORRECT HDG BECAME APPARENT ON LNDG 10-15 MINS LATER WHEN I SAW ON FINAL THAT MY HSI WAS READING 35-40 DEGS OFF THE RWY HDG/NUMBERS. CHKING THE HSI AFTER LNDG, IT WAS PROPERLY SET, NOT IN FREE SLAVE BUT READING ERRONEOUSLY.

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.

Small aircraft strayed from the biltmore class B transition corridor when his HSI precessed. ATC straightened him out.