Narrative:

We made a round trip out and back IFR training flight in rented da-40 diamond star (technically advanced aircraft). Received standard weather brief and filed flight plans via the internet. [We were] cleared as filed in both directions. First leg [was] uneventful. In and out of clouds most of the way. Flight encountered several rain showers; seldom lasting more than 5 minutes each. One shower near end of the leg was heavier than the others; lasting approximately 2 minutes. Return leg eventful. [We] experienced textbook communications failure. At cruise altitude of 5;000 ft MSL; while tuning radios to receive destination ATIS; encountered abrupt warbling noises in both headsets; rendering all radio communications and ics unusable. Observed tx and rx indications on instrument panel; believed associated with transmission keying and external signal reception. [It was] unknown if useful transmissions possible. No other electrical circuits affected [and] no popped circuit breakers. Experiencing VMC at the time; and were able to avoid rain showers along flight path; but needed descent to remain VMC. Squawked 7600; hit identify key for good measure; descended as necessary. Considered divert but ultimately rejected due to perceived inability to repair at that airport; and remained clear of their class D airspace. [We] checked all connections; attempted re-tuning radios and adjusting appropriate parameters such as squelch and volume. No effect. [We] resumed tuning radios as appropriate to phase of flight. Considered 'in-the-blind' transmissions on congested TRACON frequency; opted not to attempt due to congestion. [We] ultimately contacted TRACON via cell phone; relayed intent; and set up for visual straight-in to destination. On two mile final; all radio and ics function restored itself with no known operator intervention. Landing [was] uneventful. [We] squawked aircraft on post-flight. In our minds; the outage was associated with our previous rain shower encounters. Suspicions confirmed on chance post-flight conversation with a seasoned instructor at the FBO; he passed us and knowingly asked if we had gotten the airplane wet. Subsequent questioning intimated this aircraft is known to 'insiders' for such failures in precipitation conditions; such reputation was not known to this reporter. [We] received excellent service from ATC: learned after landing that ATC had cleared a path for us to our destination. TRACON observed our descent from 5;000 to approx 1;000 ft (to remain VMC) and were concerned we had other issues as well; which we did not. They later observed our climb back to 1;500 and by that time we were checking in via cell phone. This method of communication proved effective in relaying intent. However; these cell calls repeatedly dropped and had to be re-initiated. Debriefed occurrence with ATC facilities involved. No issues; no follow-up; all questions answered. Having an experienced safety pilot along proved enormously beneficial. We had flown before many times; including in this aircraft. We were able to discuss options and quickly make critical decisions while dividing up duties. Main message for other pilots is too periodically review far's in general; 91.185 in particular; and if encountering similar situation; remain predictable to ATC in order for them to best help you. Having a seasoned co-pilot along is usually good preflight planning!

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Original NASA ASRS Text

Title: A DA40 being flown on an IFR training flight had a communications failure while flying in rain. This particular aircraft is subject to radio failure in moisture a fact known to some at the FBO but not common knowledge to the reporter.

Narrative: We made a round trip out and back IFR training flight in rented DA-40 Diamond Star (Technically Advanced Aircraft). Received standard weather brief and filed flight plans via the internet. [We were] cleared as filed in both directions. First leg [was] uneventful. In and out of clouds most of the way. Flight encountered several rain showers; seldom lasting more than 5 minutes each. One shower near end of the leg was heavier than the others; lasting approximately 2 minutes. Return leg eventful. [We] experienced textbook communications failure. At cruise altitude of 5;000 FT MSL; while tuning radios to receive destination ATIS; encountered abrupt warbling noises in both headsets; rendering all radio communications and ICS unusable. Observed TX and RX indications on instrument panel; believed associated with transmission keying and external signal reception. [It was] unknown if useful transmissions possible. No other electrical circuits affected [and] no popped circuit breakers. Experiencing VMC at the time; and were able to avoid rain showers along flight path; but needed descent to remain VMC. Squawked 7600; hit IDENT key for good measure; descended as necessary. Considered divert but ultimately rejected due to perceived inability to repair at that airport; and remained clear of their Class D airspace. [We] checked all connections; attempted re-tuning radios and adjusting appropriate parameters such as squelch and volume. No effect. [We] resumed tuning radios as appropriate to phase of flight. Considered 'In-The-Blind' transmissions on congested TRACON frequency; opted not to attempt due to congestion. [We] ultimately contacted TRACON via cell phone; relayed intent; and set up for visual straight-in to destination. On two mile final; all radio and ICS function restored itself with no known operator intervention. Landing [was] uneventful. [We] squawked aircraft on post-flight. In our minds; the outage was associated with our previous rain shower encounters. Suspicions confirmed on chance post-flight conversation with a seasoned instructor at the FBO; he passed us and knowingly asked if we had gotten the airplane wet. Subsequent questioning intimated this aircraft is known to 'insiders' for such failures in precipitation conditions; such reputation was not known to this reporter. [We] received excellent service from ATC: Learned after landing that ATC had cleared a path for us to our destination. TRACON observed our descent from 5;000 to approx 1;000 FT (to remain VMC) and were concerned we had other issues as well; which we did not. They later observed our climb back to 1;500 and by that time we were checking in via cell phone. This method of communication proved effective in relaying intent. However; these cell calls repeatedly dropped and had to be re-initiated. Debriefed occurrence with ATC facilities involved. No issues; no follow-up; all questions answered. Having an experienced safety pilot along proved enormously beneficial. We had flown before many times; including in this aircraft. We were able to discuss options and quickly make critical decisions while dividing up duties. Main message for other pilots is too periodically review FAR's in general; 91.185 in particular; and if encountering similar situation; remain predictable to ATC in order for them to best help you. Having a seasoned Co-pilot along is usually good preflight planning!

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.