Narrative:

New maps were purchased as soon as I entered the FBO and before I asked for the airplane keys. Normal preflight included wiping oil from transponder antennas. Cleaned both. After front and back passenger loaded/belted, attempted to check rented headset before engine start with front seat passenger. He could hear me but I couldn't hear him. I estimated the radios were at least 15 yrs old. They appeared to be first generation single frequency led displays. Time was 5 mins after scheduled takeoff and 1 hour after (my) arrival at airport. The airplane was due back at FBO in 2 hours. Decided to continue without replacing headset and start flight. Listened to ATIS, contacted ground for clearance and ADIZ transponder code. Normal communication obtaining clearance. Uneventful taxi/tun-up/takeoff at hef. Tower said to contact departure. Acknowledged and switched to second radio for departure frequency (120.82) set before takeoff. Contacted (potomac) departure and received barometer setting. Heard a few communications between departure and other aircraft. Did not climb above MSL 1700 ft due to proximity of class B airspace at iad. Remained outside the aml 12 NM circle. Discussed landmarks as we flew northwest then north then northeast towards house to take pictures. Due to distance from iad and ht of ridges, was below line of sight to iad. Communication became quiet. Attributed this to below line of sight. After a few mins more of sightseeing, young rear seat passenger said stomach hurt. Ended sightseeing and began return trip. Noticed directional gyro had processed 30 degrees. Reset it to magnetic compass. Called departure on 120.82 3 times without success. Heard traffic calls on hef's tower frequency in the backgnd on the first radio. Heard departure's alternate frequency of 134.20 mentioned. Switched to 134.20 and called departure a couple of time before establishing contact. Controller said she tried to contact me for the last 30 mins, said I had a stuck (open) microphone, and had blocked the frequency for a long time. She gave me a phone number to call after landing. (End of stuck microphone problem.) she then asked what I wanted. I replied with radar vectors to hef. Although a heading of 180 degrees (magnetic) would keep me out of the class B airspace, I decided to give a wider margin and flew heading 210 degrees. The ADIZ flight plan indicated hef as both the departure and return locations. She asked me to verify squawk (ADIZ code) and say altitude. I verified squawk and reported 1700 ft MSL. She (must have) thought I was lost. She could not find me on radar and asked to climb to 2500 ft MSL and remain VFR. The transponder reply light was flashing on so many times per second it was almost continuously on. I could not understand why departure couldn't find me so close, within 20 NM of iad. I climbed to 2500 ft and reported this altitude when she asked my heading and altitude a few mins later. The heading was 210 degrees. She still didn't spot me on radar. The pitch of her voice went up a note or two. She sounded nervous. A few mins later, at approximately XA39, after still not finding me on radar, she asked me to climb to 3000 ft, remain VFR, and squawk identify 7700! Flight conditions were 3500 ft scattered, visibility 20+ mi. Although I saw no reason to squawk emergency, I complied with her request. The transponder continued to light up many times per second as it had for the entire flight. I called and said I would stop the climb at 3000 ft to maintain separation from the clouds. 3 mins later I noticed the DME wasn't getting a signal from aml (113.5) and tuned it to csn (116.3). It locked on and showed 8.4 NM. Only after I reported this to departure did she find me on radar, 4 mins after her squawk 7700 request. She said to squawk code and identify. I repeated the code and complied. Another controller then came up on frequency. He said to turn to 040 degrees, maintain 2500 ft, and remain this (134.20) frequency. I descended to 2500 ft, recognized warrenton airport (W66) and pointed it out to the front seat passenger. Departure asked me to report my position because they lost radar contact. I reported 1 NM east of warrenton. He asked me to circle until positive identify could be established (again). I started an immediate left turn (to a heading to west). He called back about 30 seconds later to report radar contact 1 NM north of warrenton and said I could proceed on course. At XA46 I was cleared to enter the class B airspace but should remain this frequency and report manassas (hef) in sight. I made no attempt to use the other radio to listen to the manassas ATIS. I felt it was critical not to change anything dealing with a radio until necessary. I reported manassas in sight less than 1 min later. He said to contact manassas tower on 133.1. He also mentioned an intermittent transponder. I contacted manassas tower and was told to enter left base for runway 34L. I acknowledged left base for runway 34L. All communications were uneventful for the rest of the flight. I heard other communications between aircraft in the pattern and the tower. After a normal landing and taxi, the aircraft was shut down and parked at the FBO ramp. I contacted the chief flight instructor upon entering the FBO office. He knew I was the pilot because he had been in the air and heard my stuck microphone conversations. I told him about the headset problem before takeoff, the stuck microphone problem, the controller perceived lost pilot situation, squawking 7700 at 3000 ft so close to iad, how long it took (departure) to find me, and departure's mention of an intermittent transponder. He grounded the airplane, took his headset and the rented one and tried to recreate the problem. Both headsets worked normally. (End of intermittent transponder problem.) I called departure on the phone and idented myself as the pilot of aircraft X. The supervisor answering the phone was aware of the entire incident. She mentioned the impact a stuck microphone had in the high traffic area of iad. She mentioned I should be aware that any time the communication gets quiet, especially in such a busy area, to check for a stuck microphone. She said no airspace restrs were violated. It was common knowledge at departure that radar coverage near csn was not very good. I relayed the chief flight instructor had grounded the airplane and aware of the other problems. She was glad to hear that.

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Original NASA ASRS Text

Title: C172. THE PLT HAD A SERIES OF AVIONICS AND INST FAILURES IN AN ACFT RENTED FROM AN FBO, NEAR THE DC ADIZ, AND DC CLASS B AIRSPACE.

Narrative: NEW MAPS WERE PURCHASED AS SOON AS I ENTERED THE FBO AND BEFORE I ASKED FOR THE AIRPLANE KEYS. NORMAL PREFLT INCLUDED WIPING OIL FROM XPONDER ANTENNAS. CLEANED BOTH. AFTER FRONT AND BACK PAX LOADED/BELTED, ATTEMPTED TO CHK RENTED HEADSET BEFORE ENG START WITH FRONT SEAT PAX. HE COULD HEAR ME BUT I COULDN'T HEAR HIM. I ESTIMATED THE RADIOS WERE AT LEAST 15 YRS OLD. THEY APPEARED TO BE FIRST GENERATION SINGLE FREQ LED DISPLAYS. TIME WAS 5 MINS AFTER SCHEDULED TKOF AND 1 HR AFTER (MY) ARR AT ARPT. THE AIRPLANE WAS DUE BACK AT FBO IN 2 HRS. DECIDED TO CONTINUE WITHOUT REPLACING HEADSET AND START FLT. LISTENED TO ATIS, CONTACTED GND FOR CLRNC AND ADIZ XPONDER CODE. NORMAL COM OBTAINING CLRNC. UNEVENTFUL TAXI/TUN-UP/TKOF AT HEF. TWR SAID TO CONTACT DEP. ACKNOWLEDGED AND SWITCHED TO SECOND RADIO FOR DEP FREQ (120.82) SET BEFORE TKOF. CONTACTED (POTOMAC) DEP AND RECEIVED BAROMETER SETTING. HEARD A FEW COMS BTWN DEP AND OTHER ACFT. DID NOT CLB ABOVE MSL 1700 FT DUE TO PROX OF CLASS B AIRSPACE AT IAD. REMAINED OUTSIDE THE AML 12 NM CIRCLE. DISCUSSED LANDMARKS AS WE FLEW NW THEN N THEN NE TOWARDS HOUSE TO TAKE PICTURES. DUE TO DISTANCE FROM IAD AND HT OF RIDGES, WAS BELOW LINE OF SIGHT TO IAD. COM BECAME QUIET. ATTRIBUTED THIS TO BELOW LINE OF SIGHT. AFTER A FEW MINS MORE OF SIGHTSEEING, YOUNG REAR SEAT PAX SAID STOMACH HURT. ENDED SIGHTSEEING AND BEGAN RETURN TRIP. NOTICED DIRECTIONAL GYRO HAD PROCESSED 30 DEGS. RESET IT TO MAGNETIC COMPASS. CALLED DEP ON 120.82 3 TIMES WITHOUT SUCCESS. HEARD TFC CALLS ON HEF'S TWR FREQ IN THE BACKGND ON THE FIRST RADIO. HEARD DEP'S ALTERNATE FREQ OF 134.20 MENTIONED. SWITCHED TO 134.20 AND CALLED DEP A COUPLE OF TIME BEFORE ESTABLISHING CONTACT. CTLR SAID SHE TRIED TO CONTACT ME FOR THE LAST 30 MINS, SAID I HAD A STUCK (OPEN) MIKE, AND HAD BLOCKED THE FREQ FOR A LONG TIME. SHE GAVE ME A PHONE NUMBER TO CALL AFTER LNDG. (END OF STUCK MIKE PROB.) SHE THEN ASKED WHAT I WANTED. I REPLIED WITH RADAR VECTORS TO HEF. ALTHOUGH A HDG OF 180 DEGS (MAGNETIC) WOULD KEEP ME OUT OF THE CLASS B AIRSPACE, I DECIDED TO GIVE A WIDER MARGIN AND FLEW HDG 210 DEGS. THE ADIZ FLT PLAN INDICATED HEF AS BOTH THE DEP AND RETURN LOCATIONS. SHE ASKED ME TO VERIFY SQUAWK (ADIZ CODE) AND SAY ALT. I VERIFIED SQUAWK AND RPTED 1700 FT MSL. SHE (MUST HAVE) THOUGHT I WAS LOST. SHE COULD NOT FIND ME ON RADAR AND ASKED TO CLB TO 2500 FT MSL AND REMAIN VFR. THE XPONDER REPLY LIGHT WAS FLASHING ON SO MANY TIMES PER SECOND IT WAS ALMOST CONTINUOUSLY ON. I COULD NOT UNDERSTAND WHY DEP COULDN'T FIND ME SO CLOSE, WITHIN 20 NM OF IAD. I CLBED TO 2500 FT AND RPTED THIS ALT WHEN SHE ASKED MY HDG AND ALT A FEW MINS LATER. THE HDG WAS 210 DEGS. SHE STILL DIDN'T SPOT ME ON RADAR. THE PITCH OF HER VOICE WENT UP A NOTE OR TWO. SHE SOUNDED NERVOUS. A FEW MINS LATER, AT APPROX XA39, AFTER STILL NOT FINDING ME ON RADAR, SHE ASKED ME TO CLB TO 3000 FT, REMAIN VFR, AND SQUAWK IDENT 7700! FLT CONDITIONS WERE 3500 FT SCATTERED, VISIBILITY 20+ MI. ALTHOUGH I SAW NO REASON TO SQUAWK EMER, I COMPLIED WITH HER REQUEST. THE XPONDER CONTINUED TO LIGHT UP MANY TIMES PER SECOND AS IT HAD FOR THE ENTIRE FLT. I CALLED AND SAID I WOULD STOP THE CLB AT 3000 FT TO MAINTAIN SEPARATION FROM THE CLOUDS. 3 MINS LATER I NOTICED THE DME WASN'T GETTING A SIGNAL FROM AML (113.5) AND TUNED IT TO CSN (116.3). IT LOCKED ON AND SHOWED 8.4 NM. ONLY AFTER I RPTED THIS TO DEP DID SHE FIND ME ON RADAR, 4 MINS AFTER HER SQUAWK 7700 REQUEST. SHE SAID TO SQUAWK CODE AND IDENT. I REPEATED THE CODE AND COMPLIED. ANOTHER CTLR THEN CAME UP ON FREQ. HE SAID TO TURN TO 040 DEGS, MAINTAIN 2500 FT, AND REMAIN THIS (134.20) FREQ. I DSNDED TO 2500 FT, RECOGNIZED WARRENTON ARPT (W66) AND POINTED IT OUT TO THE FRONT SEAT PAX. DEP ASKED ME TO RPT MY POS BECAUSE THEY LOST RADAR CONTACT. I RPTED 1 NM E OF WARRENTON. HE ASKED ME TO CIRCLE UNTIL POSITIVE IDENT COULD BE ESTABLISHED (AGAIN). I STARTED AN IMMEDIATE L TURN (TO A HDG TO W). HE CALLED BACK ABOUT 30 SECONDS LATER TO RPT RADAR CONTACT 1 NM N OF WARRENTON AND SAID I COULD PROCEED ON COURSE. AT XA46 I WAS CLRED TO ENTER THE CLASS B AIRSPACE BUT SHOULD REMAIN THIS FREQ AND RPT MANASSAS (HEF) IN SIGHT. I MADE NO ATTEMPT TO USE THE OTHER RADIO TO LISTEN TO THE MANASSAS ATIS. I FELT IT WAS CRITICAL NOT TO CHANGE ANYTHING DEALING WITH A RADIO UNTIL NECESSARY. I RPTED MANASSAS IN SIGHT LESS THAN 1 MIN LATER. HE SAID TO CONTACT MANASSAS TWR ON 133.1. HE ALSO MENTIONED AN INTERMITTENT XPONDER. I CONTACTED MANASSAS TWR AND WAS TOLD TO ENTER L BASE FOR RWY 34L. I ACKNOWLEDGED L BASE FOR RWY 34L. ALL COMS WERE UNEVENTFUL FOR THE REST OF THE FLT. I HEARD OTHER COMS BTWN ACFT IN THE PATTERN AND THE TWR. AFTER A NORMAL LNDG AND TAXI, THE ACFT WAS SHUT DOWN AND PARKED AT THE FBO RAMP. I CONTACTED THE CHIEF FLT INSTRUCTOR UPON ENTERING THE FBO OFFICE. HE KNEW I WAS THE PLT BECAUSE HE HAD BEEN IN THE AIR AND HEARD MY STUCK MIKE CONVERSATIONS. I TOLD HIM ABOUT THE HEADSET PROB BEFORE TKOF, THE STUCK MIKE PROB, THE CTLR PERCEIVED LOST PLT SIT, SQUAWKING 7700 AT 3000 FT SO CLOSE TO IAD, HOW LONG IT TOOK (DEP) TO FIND ME, AND DEP'S MENTION OF AN INTERMITTENT XPONDER. HE GNDED THE AIRPLANE, TOOK HIS HEADSET AND THE RENTED ONE AND TRIED TO RECREATE THE PROB. BOTH HEADSETS WORKED NORMALLY. (END OF INTERMITTENT XPONDER PROB.) I CALLED DEP ON THE PHONE AND IDENTED MYSELF AS THE PLT OF ACFT X. THE SUPVR ANSWERING THE PHONE WAS AWARE OF THE ENTIRE INCIDENT. SHE MENTIONED THE IMPACT A STUCK MIKE HAD IN THE HIGH TFC AREA OF IAD. SHE MENTIONED I SHOULD BE AWARE THAT ANY TIME THE COM GETS QUIET, ESPECIALLY IN SUCH A BUSY AREA, TO CHK FOR A STUCK MIKE. SHE SAID NO AIRSPACE RESTRS WERE VIOLATED. IT WAS COMMON KNOWLEDGE AT DEP THAT RADAR COVERAGE NEAR CSN WAS NOT VERY GOOD. I RELAYED THE CHIEF FLT INSTRUCTOR HAD GNDED THE AIRPLANE AND AWARE OF THE OTHER PROBS. SHE WAS GLAD TO HEAR THAT.

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.