Narrative:

The flight was a part 91 trip in my personal plane from my 3 day work week for a part 135 operation. I was on an IFR flight plan from bwi to an uncontrolled field near pittsburgh. I had received my briefing and filed my flight plan via duats just prior to the flight and was aware of the expanded tfr around P-40. When I was ready to depart; I switched from ground to the tower frequency and found that the frequency seemed to be blocked. I made my call anyway but heard no response. I switched back to ground and immediately heard 'mooney cleared for takeoff runway heading.' hearing this; I assumed there was a problem with the tower frequency and not my radio because the communications from ground control were normal. Somewhere around liftoff; I was told to contact the frequency again. When I did; the response from the tower was garbled. That was the last thing I was able to hear. When I thought I should have been handed off to departure; I made a call but was unable to get a response either. I then squawked 7600. Since it was VFR; and I could continue VFR I decided to depart the area per my fpr. If I was unable to re-establish communications; I would find a suitable place to land. I was using a hand microphone because the push-to-talk switch on the yoke had gotten a little loose in the socket and was difficult to depress. The noise or static I could hear from my radios sounded similar to a stuck microphone but not exactly. I didn't think my microphone was stuck because I could hear the audio click when I pressed the switch and also when I released it. This was a very baffling and confusing condition. I have had stuck mikes before but this condition wasn't the same. I was still on runway heading; runway 33R; while trying to sort this out and began to lose my positional awareness. Being that it was a beautiful clear day further diminished my concern for clearly monitoring my position. My clearance was for vectors to V-214 grv; direct ihd; direct. Climb to 4000 ft expect 6000 ft 10 mins after. I executed the climbs as expected and tuned in mrb the first fix in the airway. Instead of turning back to the south and intercepting V-214 like I should have; I went directly to it. I didn't think I was that far north of course; but I lost track of the time I was on runway heading as well. Had I took notice of the heading to the VOR; I would have realized how far off course I was. As it was though; I became too engrossed in solving the problem. As the frustration with the problem increased; clear thinking about what I should be doing decreased. I had the autoplt engaged in heading mode after ctring the needle but was not monitoring my course closely and wound up north of my intended route. Resolving the problem became the focus of my attention instead of navigating. Occasionally the backgnd noise would clear up momentarily. Once when I moved the switch from communication #1 to communication #2 the backgnd noise cleared up momentarily. Upon transmitting; it was back though. This anecdotal evidence of the problem turned out to be coincidental; and it further distraction me from watching my course. Then at one point; I must have inadvertently disconnected heading mode; leaving the autoplt with just the flight director engaged. Due to a heavier fuel load in the right wing; this caused the aircraft to drift north as well. At the expense of tracking the appropriate course; I ultimately discovered the problem. It was the one I should have considered to begin with. I had tried the push-to-talk switch previously and could hear it click to transmit and release so I hadn't given it any further thought. This time I wiggled it side-to-side and could detect a change in the static; almost eliminating it as I held it. I had a small screwdriver within easy reach so I removed the screws from the trim switch base to access the push-to-talk switch and saw that 1 wire had come detached and was shorting with the other. After pulling it away; communications were normal. I re-established contact with potomac approach and was told I was very close to restr airspace and to turn to heading 180 degrees. I was instructed to intercept my fpr and continued to destination. Fatigue has to be considered as well. My duty time the night before began at XA30 and ended about 1 hour before this flight at XJ00. I did not feel overly tired; but fatigue is an insidious thing.

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Original NASA ASRS Text

Title: MOONEY PLT HAS LOST COM DURING DEP AND COMES VERY CLOSE TO P-40 PROHIBITED AREA.

Narrative: THE FLT WAS A PART 91 TRIP IN MY PERSONAL PLANE FROM MY 3 DAY WORK WK FOR A PART 135 OP. I WAS ON AN IFR FLT PLAN FROM BWI TO AN UNCTLED FIELD NEAR PITTSBURGH. I HAD RECEIVED MY BRIEFING AND FILED MY FLT PLAN VIA DUATS JUST PRIOR TO THE FLT AND WAS AWARE OF THE EXPANDED TFR AROUND P-40. WHEN I WAS READY TO DEPART; I SWITCHED FROM GND TO THE TWR FREQ AND FOUND THAT THE FREQ SEEMED TO BE BLOCKED. I MADE MY CALL ANYWAY BUT HEARD NO RESPONSE. I SWITCHED BACK TO GND AND IMMEDIATELY HEARD 'MOONEY CLRED FOR TKOF RWY HDG.' HEARING THIS; I ASSUMED THERE WAS A PROB WITH THE TWR FREQ AND NOT MY RADIO BECAUSE THE COMS FROM GND CTL WERE NORMAL. SOMEWHERE AROUND LIFTOFF; I WAS TOLD TO CONTACT THE FREQ AGAIN. WHEN I DID; THE RESPONSE FROM THE TWR WAS GARBLED. THAT WAS THE LAST THING I WAS ABLE TO HEAR. WHEN I THOUGHT I SHOULD HAVE BEEN HANDED OFF TO DEP; I MADE A CALL BUT WAS UNABLE TO GET A RESPONSE EITHER. I THEN SQUAWKED 7600. SINCE IT WAS VFR; AND I COULD CONTINUE VFR I DECIDED TO DEPART THE AREA PER MY FPR. IF I WAS UNABLE TO RE-ESTABLISH COMS; I WOULD FIND A SUITABLE PLACE TO LAND. I WAS USING A HAND MIKE BECAUSE THE PUSH-TO-TALK SWITCH ON THE YOKE HAD GOTTEN A LITTLE LOOSE IN THE SOCKET AND WAS DIFFICULT TO DEPRESS. THE NOISE OR STATIC I COULD HEAR FROM MY RADIOS SOUNDED SIMILAR TO A STUCK MIKE BUT NOT EXACTLY. I DIDN'T THINK MY MIKE WAS STUCK BECAUSE I COULD HEAR THE AUDIO CLICK WHEN I PRESSED THE SWITCH AND ALSO WHEN I RELEASED IT. THIS WAS A VERY BAFFLING AND CONFUSING CONDITION. I HAVE HAD STUCK MIKES BEFORE BUT THIS CONDITION WASN'T THE SAME. I WAS STILL ON RWY HDG; RWY 33R; WHILE TRYING TO SORT THIS OUT AND BEGAN TO LOSE MY POSITIONAL AWARENESS. BEING THAT IT WAS A BEAUTIFUL CLR DAY FURTHER DIMINISHED MY CONCERN FOR CLRLY MONITORING MY POS. MY CLRNC WAS FOR VECTORS TO V-214 GRV; DIRECT IHD; DIRECT. CLB TO 4000 FT EXPECT 6000 FT 10 MINS AFTER. I EXECUTED THE CLBS AS EXPECTED AND TUNED IN MRB THE FIRST FIX IN THE AIRWAY. INSTEAD OF TURNING BACK TO THE S AND INTERCEPTING V-214 LIKE I SHOULD HAVE; I WENT DIRECTLY TO IT. I DIDN'T THINK I WAS THAT FAR N OF COURSE; BUT I LOST TRACK OF THE TIME I WAS ON RWY HDG AS WELL. HAD I TOOK NOTICE OF THE HDG TO THE VOR; I WOULD HAVE REALIZED HOW FAR OFF COURSE I WAS. AS IT WAS THOUGH; I BECAME TOO ENGROSSED IN SOLVING THE PROB. AS THE FRUSTRATION WITH THE PROB INCREASED; CLR THINKING ABOUT WHAT I SHOULD BE DOING DECREASED. I HAD THE AUTOPLT ENGAGED IN HDG MODE AFTER CTRING THE NEEDLE BUT WAS NOT MONITORING MY COURSE CLOSELY AND WOUND UP N OF MY INTENDED RTE. RESOLVING THE PROB BECAME THE FOCUS OF MY ATTN INSTEAD OF NAVING. OCCASIONALLY THE BACKGND NOISE WOULD CLR UP MOMENTARILY. ONCE WHEN I MOVED THE SWITCH FROM COM #1 TO COM #2 THE BACKGND NOISE CLRED UP MOMENTARILY. UPON XMITTING; IT WAS BACK THOUGH. THIS ANECDOTAL EVIDENCE OF THE PROB TURNED OUT TO BE COINCIDENTAL; AND IT FURTHER DISTR ME FROM WATCHING MY COURSE. THEN AT ONE POINT; I MUST HAVE INADVERTENTLY DISCONNECTED HDG MODE; LEAVING THE AUTOPLT WITH JUST THE FLT DIRECTOR ENGAGED. DUE TO A HEAVIER FUEL LOAD IN THE R WING; THIS CAUSED THE ACFT TO DRIFT N AS WELL. AT THE EXPENSE OF TRACKING THE APPROPRIATE COURSE; I ULTIMATELY DISCOVERED THE PROB. IT WAS THE ONE I SHOULD HAVE CONSIDERED TO BEGIN WITH. I HAD TRIED THE PUSH-TO-TALK SWITCH PREVIOUSLY AND COULD HEAR IT CLICK TO XMIT AND RELEASE SO I HADN'T GIVEN IT ANY FURTHER THOUGHT. THIS TIME I WIGGLED IT SIDE-TO-SIDE AND COULD DETECT A CHANGE IN THE STATIC; ALMOST ELIMINATING IT AS I HELD IT. I HAD A SMALL SCREWDRIVER WITHIN EASY REACH SO I REMOVED THE SCREWS FROM THE TRIM SWITCH BASE TO ACCESS THE PUSH-TO-TALK SWITCH AND SAW THAT 1 WIRE HAD COME DETACHED AND WAS SHORTING WITH THE OTHER. AFTER PULLING IT AWAY; COMS WERE NORMAL. I RE-ESTABLISHED CONTACT WITH POTOMAC APCH AND WAS TOLD I WAS VERY CLOSE TO RESTR AIRSPACE AND TO TURN TO HDG 180 DEGS. I WAS INSTRUCTED TO INTERCEPT MY FPR AND CONTINUED TO DEST. FATIGUE HAS TO BE CONSIDERED AS WELL. MY DUTY TIME THE NIGHT BEFORE BEGAN AT XA30 AND ENDED ABOUT 1 HR BEFORE THIS FLT AT XJ00. I DID NOT FEEL OVERLY TIRED; BUT FATIGUE IS AN INSIDIOUS THING.

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.