Narrative:

The aircraft involved in the incident was an small aircraft pressurized. After departing scranton international airport, 5 mins into the climb, I started to notice an electrical smoke within the cockpit. I turned off all electrical switches and looked for any open (popped) cbs, but none were found. Since the aircraft started pressurizing, I emergency depressurized the aircraft to open the side window for ventilation. I contacted the departure facility of my situation, and made a 180 degree turn back towards the field. ATC told me to contact the tower and I did so. By the time I had entered downwind the smoke started to dissipate and I started the 'before landing checklist' but the landing gear would not come down. I then emergency extended the gear with the appropriate checklist. I was assured that the gear was down and locked, and landed. The maintenance personnel jacked the aircraft to determine the problem and found that the motor/pump assembly had not developed enough pressure to turn the motor 'off' with the pressure sensing switch. The motor had continued to run against a load causing the smoke. I feel that this situation should be brought to the attention of owners and operators, and further investigation should be accomplished with this incident. The motor which burned up had been installed in 1988, which means it could be a recurring problem. I encourage NASA to call me for any questions they might have and contact the maintenance personnel of (FBO) for a detailed description of the work performed. Callback conversation with reporter revealed the following information. Unable to contact reporter. Analyst checked with mechanic who indicated the micro switch and pump are checked as normal part of the 100 hour or annual inspection. The switch may get out of adjustment or just suffer 'wear and tear'. Pressure within pump is checked also and loss of pressure may be due to piston wear or not enough fluid.

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Original NASA ASRS Text

Title: SMA PLT HAS SMOKE IN COCKPIT DURING INITIAL CLIMB. RETURN TO LAND. NEEDS EMERGENCY GEAR EXTENSION.

Narrative: THE ACFT INVOLVED IN THE INCIDENT WAS AN SMA PRESSURIZED. AFTER DEPARTING SCRANTON INTL ARPT, 5 MINS INTO THE CLB, I STARTED TO NOTICE AN ELECTRICAL SMOKE WITHIN THE COCKPIT. I TURNED OFF ALL ELECTRICAL SWITCHES AND LOOKED FOR ANY OPEN (POPPED) CBS, BUT NONE WERE FOUND. SINCE THE ACFT STARTED PRESSURIZING, I EMER DEPRESSURIZED THE ACFT TO OPEN THE SIDE WINDOW FOR VENTILATION. I CONTACTED THE DEP FAC OF MY SITUATION, AND MADE A 180 DEG TURN BACK TOWARDS THE FIELD. ATC TOLD ME TO CONTACT THE TWR AND I DID SO. BY THE TIME I HAD ENTERED DOWNWIND THE SMOKE STARTED TO DISSIPATE AND I STARTED THE 'BEFORE LNDG CHKLIST' BUT THE LNDG GEAR WOULD NOT COME DOWN. I THEN EMER EXTENDED THE GEAR WITH THE APPROPRIATE CHKLIST. I WAS ASSURED THAT THE GEAR WAS DOWN AND LOCKED, AND LANDED. THE MAINT PERSONNEL JACKED THE ACFT TO DETERMINE THE PROBLEM AND FOUND THAT THE MOTOR/PUMP ASSEMBLY HAD NOT DEVELOPED ENOUGH PRESSURE TO TURN THE MOTOR 'OFF' WITH THE PRESSURE SENSING SWITCH. THE MOTOR HAD CONTINUED TO RUN AGAINST A LOAD CAUSING THE SMOKE. I FEEL THAT THIS SITUATION SHOULD BE BROUGHT TO THE ATTN OF OWNERS AND OPERATORS, AND FURTHER INVESTIGATION SHOULD BE ACCOMPLISHED WITH THIS INCIDENT. THE MOTOR WHICH BURNED UP HAD BEEN INSTALLED IN 1988, WHICH MEANS IT COULD BE A RECURRING PROBLEM. I ENCOURAGE NASA TO CALL ME FOR ANY QUESTIONS THEY MIGHT HAVE AND CONTACT THE MAINT PERSONNEL OF (FBO) FOR A DETAILED DESCRIPTION OF THE WORK PERFORMED. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO. UNABLE TO CONTACT RPTR. ANALYST CHKED WITH MECH WHO INDICATED THE MICRO SWITCH AND PUMP ARE CHKED AS NORMAL PART OF THE 100 HR OR ANNUAL INSPECTION. THE SWITCH MAY GET OUT OF ADJUSTMENT OR JUST SUFFER 'WEAR AND TEAR'. PRESSURE WITHIN PUMP IS CHKED ALSO AND LOSS OF PRESSURE MAY BE DUE TO PISTON WEAR OR NOT ENOUGH FLUID.

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.