Narrative:

I was flying the RNAV/GPS runway 34 approach into ZZZ. My intention was to circle to land runway 16 and taxi back for a departure back to my base; allowing another flight awaiting release to takeoff in front of me. After switching to the CTAF; I was maintaining 2;000 ft outside of the FAF. The overcast ceiling appeared to be about 100-200 ft below me; and closer in some locations. A few miles from the FAF; my GPS lost its signal; giving a large warning on the screen and freezing the moving map. At nearly the same time a whooping alarm went off; which I attributed to the GPS failure. As I was about to enter IMC; I initiated a climb and turned southward; where the clouds were sct/broken and not ovc.when established on a course away from IMC; I changed frequencies back to approach but my radio was overpowered by the alarm. I turned down the volume of my communication 1; which shares a screen with my GPS; and went to communication 2; which is controlled by the same radio panel; but on a different box. Here; too; the alarm was overpowering and I could not hear any return calls. At this point; I continued my climb to 5;500 to stay well above the clouds--knowing I was flying over a large body of water--and squawked 7600. I also tried calling on my hand-held transceiver but received the same alarm. When I was established southward; I attempted to dial in a VOR; but was unable. VOR 1 was not working at all; even when I cycled the GPS from GPS mode to vloc mode.I attempted to call approach from my cell phone; but lost my signal before the call went through. For the first part of this leg; my only visual cue was the mountain; well in the distance; which I knew was the direction I needed to navigate to ZZZ1. I also had the ZZZ1 NDB dialed in; and it appeared to be pointing the correct direction. Through a break in the clouds; I noticed the tip of the port and used that to get a bearing on ZZZ2. With a general idea of how to get to ZZZ2; I attempted to descend below the clouds; but found that doing so would take me to about 1;500 ft; which I decided was unsafe for overwater operations; and I climbed back to 5;500. When I spotted ZZZ2; I opted not to overfly; as they appeared to have a broken/ovc layer at about 2;500-3;000; and instead elected to start descending over the water to get below the layer. At this point; I was quite familiar with the local area and knew I could navigate visually to ZZZ1. A few miles west of ZZZ2; I retried my radios; and still found the alarm going off. I noticed a faint flashing light next to my ELT reset switch and upon hitting that the alarm stopped. I do not know why the ELT would have gone off during the flight; but likely did not see the light because I was wearing sunglasses and the cockpit was quite bright with direct sunlight. I had earlier dismissed the problem as being an ELT because I believed it only broadcast on 121.5. Hearing the alarm on every frequency; both from my airplane's radios and my handheld; led me to believe something else in the airplane had failed and was giving an alarm that seemingly jammed every frequency. I could not imagine that an emergency frequency would also mask a pilot's ability to hear any frequency; which seems extremely dangerous.having cut out the alarm; I called center on a frequency I knew from having flown many practice approaches into ZZZ2. I explained that I was the aircraft on lost comm and had re-established radio contact. I switched my squawk to 1200 and flew with flight following back to ZZZ1 for an uneventful visual landing. About 20-30 NM from ZZZ1; I noticed my GPS working again; but don't recall it working when passing ZZZ2.after landing; I was asked to call approach. Upon doing so; I explained what happened and they confirmed that they had not heard any of my calls when I had first attempted to try them after the alarm went off. I believe the most significant problem during this flight was my not realizing the ELT was going off and the source of the alarm. Nothing during the flight triggered me to think the ELT could have gone off. Additionally; I was confused by the alarm being heard on every frequency; which did not seem to make sense; and rather seemed dangerous as it greatly limited my ability to communicate. Had the light signaling that the ELT was on been more noticeable I likely would have noticed it quickly. I cannot say for sure whether my radios and hand held were actually broken; or if the ELT just effectively disabled them with its alarm. The ear-piercing alarm was certainly very stress-inducing; seemingly a constant reminder of my inability to talk to anyone while flying close to IMC.

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Original NASA ASRS Text

Title: A C-172 pilot experienced a loss of navigation and communication capability while initiating an instrument approach. He abandoned the approach; remained VFR; squawked 7600 and utilized visible ground checkpoints with which he was familiar to re-establish himself in VMC to return to his departure airport.

Narrative: I was flying the RNAV/GPS Runway 34 approach into ZZZ. My intention was to circle to land Runway 16 and taxi back for a departure back to my base; allowing another flight awaiting release to takeoff in front of me. After switching to the CTAF; I was maintaining 2;000 FT outside of the FAF. The overcast ceiling appeared to be about 100-200 FT below me; and closer in some locations. A few miles from the FAF; my GPS lost its signal; giving a large warning on the screen and freezing the moving map. At nearly the same time a whooping alarm went off; which I attributed to the GPS failure. As I was about to enter IMC; I initiated a climb and turned southward; where the clouds were SCT/BKN and not OVC.When established on a course away from IMC; I changed frequencies back to Approach but my radio was overpowered by the alarm. I turned down the volume of my COM 1; which shares a screen with my GPS; and went to COM 2; which is controlled by the same radio panel; but on a different box. Here; too; the alarm was overpowering and I could not hear any return calls. At this point; I continued my climb to 5;500 to stay well above the clouds--knowing I was flying over a large body of water--and squawked 7600. I also tried calling on my hand-held transceiver but received the same alarm. When I was established southward; I attempted to dial in a VOR; but was unable. VOR 1 was not working at all; even when I cycled the GPS from GPS mode to VLOC mode.I attempted to call Approach from my cell phone; but lost my signal before the call went through. For the first part of this leg; my only visual cue was the mountain; well in the distance; which I knew was the direction I needed to navigate to ZZZ1. I also had the ZZZ1 NDB dialed in; and it appeared to be pointing the correct direction. Through a break in the clouds; I noticed the tip of the port and used that to get a bearing on ZZZ2. With a general idea of how to get to ZZZ2; I attempted to descend below the clouds; but found that doing so would take me to about 1;500 FT; which I decided was unsafe for overwater operations; and I climbed back to 5;500. When I spotted ZZZ2; I opted not to overfly; as they appeared to have a BKN/OVC layer at about 2;500-3;000; and instead elected to start descending over the water to get below the layer. At this point; I was quite familiar with the local area and knew I could navigate visually to ZZZ1. A few miles west of ZZZ2; I retried my radios; and still found the alarm going off. I noticed a faint flashing light next to my ELT reset switch and upon hitting that the alarm stopped. I do not know why the ELT would have gone off during the flight; but likely did not see the light because I was wearing sunglasses and the cockpit was quite bright with direct sunlight. I had earlier dismissed the problem as being an ELT because I believed it only broadcast on 121.5. Hearing the alarm on every frequency; both from my airplane's radios and my handheld; led me to believe something else in the airplane had failed and was giving an alarm that seemingly jammed every frequency. I could not imagine that an emergency frequency would also mask a pilot's ability to hear any frequency; which seems extremely dangerous.Having cut out the alarm; I called Center on a frequency I knew from having flown many practice approaches into ZZZ2. I explained that I was the aircraft on Lost COMM and had re-established radio contact. I switched my squawk to 1200 and flew with flight following back to ZZZ1 for an uneventful visual landing. About 20-30 NM from ZZZ1; I noticed my GPS working again; but don't recall it working when passing ZZZ2.After landing; I was asked to call Approach. Upon doing so; I explained what happened and they confirmed that they had not heard any of my calls when I had first attempted to try them after the alarm went off. I believe the most significant problem during this flight was my not realizing the ELT was going off and the source of the alarm. Nothing during the flight triggered me to think the ELT could have gone off. Additionally; I was confused by the alarm being heard on every frequency; which did not seem to make sense; and rather seemed dangerous as it greatly limited my ability to communicate. Had the light signaling that the ELT was on been more noticeable I likely would have noticed it quickly. I cannot say for sure whether my radios and hand held were actually broken; or if the ELT just effectively disabled them with its alarm. The ear-piercing alarm was certainly very stress-inducing; seemingly a constant reminder of my inability to talk to anyone while flying close to IMC.

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.