Narrative:

Departing sac for an end of the day flight to oak. Flight delayed due to weather into sac then delayed into oak due to surface check of the runways. Departed at XA09. Uneventful; except the handoff from travis approach to oakland center was not successful. I contacted oakland center several times with no response. I contacted travis and they gave another frequency to try. Attempts on that frequency got a 'transmission broken' message from oak. Arrived at popes intersection (V494/V87) and made the turn onto the appropriate radial (167 heading) at the appropriate DME and centered the needle. Since no other VOR until vectors; navigation 1 and 2 were set to sgd and centered. Needles began to fluctuate 4 degrees left; then 4 degrees right; taking about 3 seconds to complete a cycle. Since oak VOR is known to do this when coming in from the north; I accepted this as simply a VOR issue. Approximately 17 nm from sgd; the needle suddenly went full deflection right. I assumed it would deflect back to the left; but realized it was not doing so. Began to diagnose the issue when oakland center informed me I was not following my assigned route of flight and should immediately turn 30-40 degrees left and to acknowledge with an identification on frequency. I immediately complied and once back on the airway; now 12 nm from sgd; I contacted oakland again and they were able to receive my transmission. However; continued to have transmission issues and utilized ident to acknowledge several times until handed off to norcal where again I had no issues with communications. Thoughts: the plane had been parked in a heavy downpour for the entire day; resulting in the breaker panel being soaked in water and a breaker popping as soon as power was applied to the panel (master on). Plane performed acceptably on the leg to sac with marginal; but acceptable; performance of the VOR system until within about 60 nm of sac. Possible that the antenna housing allowed water to penetrate which then quickly froze (14000 ft enroute) then that thawed once I was on the ground in sac awaiting oak to confirm no damage to runways. My carrier was notified of erroneous readings on the VOR system via company procedure; I have not received a response as to the results of their testing procedures. While the problem was discovered about when ATC notified me I was off course; a contributing factor was my continued attempts to raise ATC on the assigned frequencies. This distraction of hard IMC; hand flying; and attempting to establish radio communications with ATC probably delayed diagnosis of the problem until later. In addition; due to weather; the flight extended duty day to 15.5 hours. The unusual east plan (e.g. Approaches via sgd; 90% of oak approaches are on the west plan via sunol intersection and an ILS); long day and lack of recent flight time (60ish days) in model added to the stress and diagnosis delay. My estimate based on time to re-intercept airway would be 4-5 nm off centerline. Possible solutions: my company is in the process of equipping its planes with IFR GPS's. Use of such device would have brought the VOR issue into focus and eliminated the off course issue. It may have also resulted in notifying ATC of an issue related to the sgd VOR and the 347 degree radial. Unfortunately; due to the panel configuration; I cannot say if this was an aircraft issue or a VOR issue.

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Original NASA ASRS Text

Title: A light twin pilot described his radio and navaid anomalies while flying airways after the aircraft had been parked with the aircraft's circuit breakers exposed to rain and weather elements.

Narrative: Departing SAC for an end of the day flight to OAK. Flight delayed due to weather into SAC then delayed into OAK due to surface check of the runways. Departed at XA09. Uneventful; except the handoff from Travis Approach to Oakland Center was not successful. I contacted Oakland Center several times with no response. I contacted Travis and they gave another frequency to try. Attempts on that frequency got a 'transmission broken' message from OAK. Arrived at POPES intersection (V494/V87) and made the turn onto the appropriate radial (167 heading) at the appropriate DME and centered the needle. Since no other VOR until vectors; NAV 1 and 2 were set to SGD and centered. Needles began to fluctuate 4 degrees left; then 4 degrees right; taking about 3 seconds to complete a cycle. Since OAK VOR is known to do this when coming in from the North; I accepted this as simply a VOR issue. Approximately 17 nm from SGD; the needle suddenly went full deflection right. I assumed it would deflect back to the left; but realized it was not doing so. Began to diagnose the issue when Oakland Center informed me I was not following my assigned route of flight and should immediately turn 30-40 degrees left and to acknowledge with an identification on frequency. I immediately complied and once back on the airway; now 12 nm from SGD; I contacted Oakland again and they were able to receive my transmission. However; continued to have transmission issues and utilized ident to acknowledge several times until handed off to Norcal where again I had no issues with communications. Thoughts: the plane had been parked in a heavy downpour for the entire day; resulting in the breaker panel being soaked in water and a breaker popping as soon as power was applied to the panel (Master on). Plane performed acceptably on the leg to SAC with marginal; but acceptable; performance of the VOR system until within about 60 nm of SAC. Possible that the antenna housing allowed water to penetrate which then quickly froze (14000 FT enroute) then that thawed once I was on the ground in SAC awaiting OAK to confirm no damage to runways. My Carrier was notified of erroneous readings on the VOR system via Company procedure; I have not received a response as to the results of their testing procedures. While the problem was discovered about when ATC notified me I was off course; a contributing factor was my continued attempts to raise ATC on the assigned frequencies. This distraction of hard IMC; hand flying; and attempting to establish radio communications with ATC probably delayed diagnosis of the problem until later. In addition; due to weather; the flight extended duty day to 15.5 hours. The unusual east plan (e.g. approaches via SGD; 90% of OAK approaches are on the west plan via SUNOL intersection and an ILS); long day and lack of recent flight time (60ish days) in model added to the stress and diagnosis delay. My estimate based on time to re-intercept airway would be 4-5 nm off centerline. Possible solutions: My Company is in the process of equipping its planes with IFR GPS's. Use of such device would have brought the VOR issue into focus and eliminated the off course issue. It may have also resulted in notifying ATC of an issue related to the SGD VOR and the 347 degree radial. Unfortunately; due to the panel configuration; I cannot say if this was an aircraft issue or a VOR issue.

Data retrieved from NASA's ASRS site as of April 2012 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.