Pilot of a twin turboprop flew a round robin trip through an ADIZ zone without a transponder on with...

Attributes
ACN	490610
Time
Date	200010
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : ome.airport
State Reference	AK
Altitude	msl single value : 9500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	general aviation : corporate
Make Model Name	Small Transport, Low Wing, 2 Turboprop Eng
Operating Under FAR Part	Part 91
Flight Phase	climbout : initial cruise : level descent : approach
Route In Use	enroute airway : zzz.airway
Flight Plan	DVR
Person 1
Affiliation	company : corporate
Function	flight crew : single pilot
Qualification	pilot : commercial pilot : multi engine pilot : instrument
ASRS Report	490610
Person 2
Affiliation	government : faa
Function	other personnel
Qualification	other
Events
Anomaly	aircraft equipment problem : less severe non adherence : far non adherence : published procedure
Independent Detector	atc equipment other atc equipment : radar other controllera
Resolutory Action	none taken : detected after the fact
Consequence	faa : reviewed incident with flight crew other
Supplementary
Problem Areas	Flight Crew Human Performance Aircraft
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

I was the PIC of a flight that returned to nome, ak (ome), from gambell, ak (gam), in an ADIZ on a round robin DVFR flight plan with no transponder. Nome FSS informed me when I called in for an airport advisory. The #1 transponder was on the proper code, and in altitude mode, but the selector switch was selected to #2 transponder which was in standby. As I approached gam on the ome-gam leg, a snowshower moved over the gam airport reducing visibility. I changed DME from #1 to #2, which was tuned to gam for a holding position. As I was switching DME's, I could see the village and airport appear behind the shower and did not bother to verify the DME. On the return leg to ome, after leveling off at 9500 ft, the aircraft gyro pressurization dropped to zero psi, failing all of the air driven gyros. This was not a problem for the flight because of good VMC for the flight. I was preoccupied with troubleshooting the gyro pressure problem and did not verify the transponder reply light. I must have selected #2 transponder instead of #2 DME when approaching gam. Adhering to the basic rule of verifying everything you do with a switch or control really would have helped to cause what I wanted to happen. Being preoccupied with a problem prevented what I wanted to happen.

Original NASA ASRS Text

Title: PLT OF A TWIN TURBOPROP FLEW A ROUND ROBIN TRIP THROUGH AN ADIZ ZONE WITHOUT A XPONDER ON WITH ASSIGNED CODE AND ALT DUE TO SELECTING THE #2 XPONDER WHICH WAS IN STANDBY.

Narrative: I WAS THE PIC OF A FLT THAT RETURNED TO NOME, AK (OME), FROM GAMBELL, AK (GAM), IN AN ADIZ ON A ROUND ROBIN DVFR FLT PLAN WITH NO XPONDER. NOME FSS INFORMED ME WHEN I CALLED IN FOR AN ARPT ADVISORY. THE #1 XPONDER WAS ON THE PROPER CODE, AND IN ALT MODE, BUT THE SELECTOR SWITCH WAS SELECTED TO #2 XPONDER WHICH WAS IN STANDBY. AS I APCHED GAM ON THE OME-GAM LEG, A SNOWSHOWER MOVED OVER THE GAM ARPT REDUCING VISIBILITY. I CHANGED DME FROM #1 TO #2, WHICH WAS TUNED TO GAM FOR A HOLDING POS. AS I WAS SWITCHING DME'S, I COULD SEE THE VILLAGE AND ARPT APPEAR BEHIND THE SHOWER AND DID NOT BOTHER TO VERIFY THE DME. ON THE RETURN LEG TO OME, AFTER LEVELING OFF AT 9500 FT, THE ACFT GYRO PRESSURIZATION DROPPED TO ZERO PSI, FAILING ALL OF THE AIR DRIVEN GYROS. THIS WAS NOT A PROB FOR THE FLT BECAUSE OF GOOD VMC FOR THE FLT. I WAS PREOCCUPIED WITH TROUBLESHOOTING THE GYRO PRESSURE PROB AND DID NOT VERIFY THE XPONDER REPLY LIGHT. I MUST HAVE SELECTED #2 XPONDER INSTEAD OF #2 DME WHEN APCHING GAM. ADHERING TO THE BASIC RULE OF VERIFYING EVERYTHING YOU DO WITH A SWITCH OR CTL REALLY WOULD HAVE HELPED TO CAUSE WHAT I WANTED TO HAPPEN. BEING PREOCCUPIED WITH A PROB PREVENTED WHAT I WANTED TO HAPPEN.

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.

Pilot of a twin turboprop flew a round robin trip through an ADIZ zone without a transponder on with assigned code and altitude due to selecting the #2 transponder which was in standby.