Narrative:

I completed a standard preflight on a cessna C150 with a 180 hp engine. The instrument panel was covered with a new security shield over the avionics which I removed during the preflight. After engine start, contacts with ATIS, clearance delivery, and ground control were normal. A clearance was read back correctly in the run-up area and it was then that I realized the transponder was missing. We previously had the DME out of the airplane for repairs so the empty slot didn't look unusual. After I went through an emotional verbiage of disgust on what I thought was the intercom, ground control advised me that I had a stuck microphone. After an apology to the tower folks, I found the source of that problem which was the push to talk switch on the yoke. Next I asked the tower if I could go IFR without the transponder and they said they were trying to coordinate it. The reply from approach was that I couldn't go IFR in the class B without a transponder (that made sense and relieved me of the mental burden of having filed an equipment code as a slant a with transponder). The tower said I would have to remain clear of the class B airspace. The tower asked if I wanted a downwind departure (it was VFR) and I accepted. We took off VFR and stayed clear of the class B airspace. Unable to even squawk 1200, I was grateful for the VFR departure. My first problem was not realizing the transponder was missing during preflight. Interestingly, the preflight was not rushed. It was pretty complete but complicated by the new non-standard security panel and by me being used to a 'hole' in the panel when the DME was being repaired. The second problem was the stuck microphone (mechanical). The third problem was having to fly within the 30 mi veil without mode C even though coordinated with ATC. Approach control doesn't need any additional challenges even when there is little traffic. All this could have been prevented. A better preflight before engine start would have recognized the transponder problem. Seeing the small 'T' on the radio might have made me realize the push to talk button was stuck.

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Original NASA ASRS Text

Title: SMA PLT HAD STUCK MIKE AND DISCOVERED NO XPONDER IN THE ACFT. HE HAD FILED AN IFR FLT PLAN.

Narrative: I COMPLETED A STANDARD PREFLT ON A CESSNA C150 WITH A 180 HP ENG. THE INST PANEL WAS COVERED WITH A NEW SECURITY SHIELD OVER THE AVIONICS WHICH I REMOVED DURING THE PREFLT. AFTER ENG START, CONTACTS WITH ATIS, CLRNC DELIVERY, AND GND CTL WERE NORMAL. A CLRNC WAS READ BACK CORRECTLY IN THE RUN-UP AREA AND IT WAS THEN THAT I REALIZED THE XPONDER WAS MISSING. WE PREVIOUSLY HAD THE DME OUT OF THE AIRPLANE FOR REPAIRS SO THE EMPTY SLOT DIDN'T LOOK UNUSUAL. AFTER I WENT THROUGH AN EMOTIONAL VERBIAGE OF DISGUST ON WHAT I THOUGHT WAS THE INTERCOM, GND CTL ADVISED ME THAT I HAD A STUCK MIKE. AFTER AN APOLOGY TO THE TWR FOLKS, I FOUND THE SOURCE OF THAT PROB WHICH WAS THE PUSH TO TALK SWITCH ON THE YOKE. NEXT I ASKED THE TWR IF I COULD GO IFR WITHOUT THE XPONDER AND THEY SAID THEY WERE TRYING TO COORDINATE IT. THE REPLY FROM APCH WAS THAT I COULDN'T GO IFR IN THE CLASS B WITHOUT A XPONDER (THAT MADE SENSE AND RELIEVED ME OF THE MENTAL BURDEN OF HAVING FILED AN EQUIP CODE AS A SLANT A WITH XPONDER). THE TWR SAID I WOULD HAVE TO REMAIN CLR OF THE CLASS B AIRSPACE. THE TWR ASKED IF I WANTED A DOWNWIND DEP (IT WAS VFR) AND I ACCEPTED. WE TOOK OFF VFR AND STAYED CLR OF THE CLASS B AIRSPACE. UNABLE TO EVEN SQUAWK 1200, I WAS GRATEFUL FOR THE VFR DEP. MY FIRST PROB WAS NOT REALIZING THE XPONDER WAS MISSING DURING PREFLT. INTERESTINGLY, THE PREFLT WAS NOT RUSHED. IT WAS PRETTY COMPLETE BUT COMPLICATED BY THE NEW NON-STANDARD SECURITY PANEL AND BY ME BEING USED TO A 'HOLE' IN THE PANEL WHEN THE DME WAS BEING REPAIRED. THE SECOND PROB WAS THE STUCK MIKE (MECHANICAL). THE THIRD PROB WAS HAVING TO FLY WITHIN THE 30 MI VEIL WITHOUT MODE C EVEN THOUGH COORDINATED WITH ATC. APCH CTL DOESN'T NEED ANY ADDITIONAL CHALLENGES EVEN WHEN THERE IS LITTLE TFC. ALL THIS COULD HAVE BEEN PREVENTED. A BETTER PREFLT BEFORE ENG START WOULD HAVE RECOGNIZED THE XPONDER PROB. SEEING THE SMALL 'T' ON THE RADIO MIGHT HAVE MADE ME REALIZE THE PUSH TO TALK BUTTON WAS STUCK.

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.