Small transport crew declares an emergency after a shower of sparks is caused by propeller heat.

Attributes
ACN	147484
Time
Date	199006
Day	Sun
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : hto airport : hpn
State Reference	NY
Altitude	msl bound lower : 15000 msl bound upper : 15000
Environment
Flight Conditions	Mixed
Light	Night
Aircraft 1
Controlling Facilities	artcc : zny
Operator	general aviation : corporate
Make Model Name	Small Transport, Low Wing, 2 Recip Eng
Flight Phase	climbout : intermediate altitude cruise other
Route In Use	enroute : direct enroute other
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : atp pilot : cfi
Experience	flight time last 90 days : 100 flight time total : 4200 flight time type : 42
ASRS Report	147484
Person 2
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Events
Anomaly	aircraft equipment problem : less severe
Independent Detector	other flight crewa
Resolutory Action	flight crew : declared emergency flight crew : overcame equipment problem other
Consequence	Other
Supplementary
Primary Problem	Aircraft

Narrative:

Approximately 3 mins prior to leveling at 15000' from a climb, I turned the propeller heat switch to the on position. A short time after leveling off, a series of very bright flashes (lighting up the cockpit) appeared through the pilot's left side window. At first I thought it was a massive lightning display, but when I looked outside, I saw a stream of sparks coming form behind my left engine propeller. I assessed the situation and turned off the propeller heat switch. The sparks ceased. I declared an emergency and turned directly for hpn. I landed west/O incident. Due to the WX and my position (approximately 30 NM over water), declaring an emergency to an airport for a landing west/O delay was what I felt to be necessary in order to ensure a safe outcome. The problem was caused by worn brushes on the left propeller plate. I believe that I acted properly and effectively. I had just completed the small transport initial training course on 5/fri/90. The brushes are being replaced today during routing 50 phase inspection. Brushes on both propellers are being changed.

Original NASA ASRS Text

Title: SMT CREW DECLARES AN EMER AFTER A SHOWER OF SPARKS IS CAUSED BY PROPELLER HEAT.

Narrative: APPROX 3 MINS PRIOR TO LEVELING AT 15000' FROM A CLB, I TURNED THE PROP HEAT SWITCH TO THE ON POS. A SHORT TIME AFTER LEVELING OFF, A SERIES OF VERY BRIGHT FLASHES (LIGHTING UP THE COCKPIT) APPEARED THROUGH THE PLT'S LEFT SIDE WINDOW. AT FIRST I THOUGHT IT WAS A MASSIVE LIGHTNING DISPLAY, BUT WHEN I LOOKED OUTSIDE, I SAW A STREAM OF SPARKS COMING FORM BEHIND MY LEFT ENG PROP. I ASSESSED THE SITUATION AND TURNED OFF THE PROP HEAT SWITCH. THE SPARKS CEASED. I DECLARED AN EMER AND TURNED DIRECTLY FOR HPN. I LANDED W/O INCIDENT. DUE TO THE WX AND MY POS (APPROX 30 NM OVER WATER), DECLARING AN EMER TO AN ARPT FOR A LNDG W/O DELAY WAS WHAT I FELT TO BE NECESSARY IN ORDER TO ENSURE A SAFE OUTCOME. THE PROB WAS CAUSED BY WORN BRUSHES ON THE LEFT PROP PLATE. I BELIEVE THAT I ACTED PROPERLY AND EFFECTIVELY. I HAD JUST COMPLETED THE SMT INITIAL TRNING COURSE ON 5/FRI/90. THE BRUSHES ARE BEING REPLACED TODAY DURING RTING 50 PHASE INSPECTION. BRUSHES ON BOTH PROPS ARE BEING CHANGED.

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.