BE99 single pilot incurs both navigation and heading problems while in IMC.

Attributes
ACN	690117
Time
Date	200603
Local Time Of Day	0001 To 0600
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	msl bound lower : 7700 msl bound upper : 9000
Environment
Flight Conditions	IMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zlc.artcc
Operator	common carrier : air taxi
Make Model Name	Airliner 99
Operating Under FAR Part	Part 135
Flight Phase	descent : approach
Flight Plan	IFR
Person 1
Affiliation	company : air taxi
Function	flight crew : single pilot
Qualification	pilot : instrument pilot : multi engine pilot : atp pilot : cfi
Experience	flight time last 90 days : 60 flight time total : 5671 flight time type : 900
ASRS Report	690117
Person 2
Affiliation	government : faa
Function	controller : radar
Events
Anomaly	aircraft equipment problem : less severe
Independent Detector	aircraft equipment other aircraft equipment : vor receivers other flight crewa
Resolutory Action	flight crew : became reoriented flight crew : overcame equipment problem
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance

Narrative:

While flying a BE99 for a part 135 cargo company; it appeared as my 2 VOR receivers were not giving correct information; as well as having an inaccurate ADF receiver and a gyro which was 20 degrees off my compass heading while initiating an ILS approach in IMC. After doing some troubleshooting I was able to ascertain that one of the VOR receivers was still in GPS mode as I had a GPS (VFR) only on board. Now I had 1 operative VOR receiver. Also my heading indicator was 20 degrees off when I set it to the whiskey compass. I learned that it was prohibited to set the heading indicator with the use of windshield heat on. This information was not placarded in the airplane. Because of the inaccurate heading indicator; the ADF needle was also 20 degrees off. After these problems were resolved; I was able to complete the approach successfully with the use of 1 VOR receiver. My conclusion is that for an accident to occur several breaks in a chain must occur. I was single pilot IMC at the time with less than 100 hours PIC in the aircraft. Fortunately I was able to correct the situation. One of my recommendations is to placard 'do not use windshield heat while resetting the heading indicator' on the aircraft.

Original NASA ASRS Text

Title: BE99 SINGLE PLT INCURS BOTH NAV AND HDG PROBS WHILE IN IMC.

Narrative: WHILE FLYING A BE99 FOR A PART 135 CARGO COMPANY; IT APPEARED AS MY 2 VOR RECEIVERS WERE NOT GIVING CORRECT INFO; AS WELL AS HAVING AN INACCURATE ADF RECEIVER AND A GYRO WHICH WAS 20 DEGS OFF MY COMPASS HDG WHILE INITIATING AN ILS APCH IN IMC. AFTER DOING SOME TROUBLESHOOTING I WAS ABLE TO ASCERTAIN THAT ONE OF THE VOR RECEIVERS WAS STILL IN GPS MODE AS I HAD A GPS (VFR) ONLY ON BOARD. NOW I HAD 1 OPERATIVE VOR RECEIVER. ALSO MY HDG INDICATOR WAS 20 DEGS OFF WHEN I SET IT TO THE WHISKEY COMPASS. I LEARNED THAT IT WAS PROHIBITED TO SET THE HDG INDICATOR WITH THE USE OF WINDSHIELD HEAT ON. THIS INFO WAS NOT PLACARDED IN THE AIRPLANE. BECAUSE OF THE INACCURATE HDG INDICATOR; THE ADF NEEDLE WAS ALSO 20 DEGS OFF. AFTER THESE PROBS WERE RESOLVED; I WAS ABLE TO COMPLETE THE APCH SUCCESSFULLY WITH THE USE OF 1 VOR RECEIVER. MY CONCLUSION IS THAT FOR AN ACCIDENT TO OCCUR SEVERAL BREAKS IN A CHAIN MUST OCCUR. I WAS SINGLE PLT IMC AT THE TIME WITH LESS THAN 100 HRS PIC IN THE ACFT. FORTUNATELY I WAS ABLE TO CORRECT THE SITUATION. ONE OF MY RECOMMENDATIONS IS TO PLACARD 'DO NOT USE WINDSHIELD HEAT WHILE RESETTING THE HDG INDICATOR' ON THE ACFT.

Data retrieved from NASA's ASRS site as of January 2009 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.