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 Without getting into an electrical engineering discussion about joules vs. watts vs. amps vs. the amount of time in use, etc., the bottom line as far as we pilots are concerned is this: Amps (current ‘f low’) and wattage along with voltage (potential for electron ‘move- ment’), wire size and material (alu- minum, copper, gold, etc.) generate varying amounts of heat – enough heat and you get fire. An open circuit is cold (literally, room temperature). An in-use circuit should produce virtually no heat. A circuit that has too much current for the size of wire will get hot – possibly hot enough to start a fire. And fire + airplane = bad. Even more so than an engine failure, an electrical fire will get your attention, so we need to recognize the early signs of an overheat or fire. Ozone, Hot Plastic and Smoke Electrical smell, vapor, smoke and flames will be our indication of a seri- ous electrical problem. And you may notice one or more of these before your carbon monoxide/smoke detec- tor sounds an alarm. When electricity arcs through air, as it sometimes does with a DC electric motor or between a bare wire and ground, it splits oxy- gen and nitrogen into a form of oxy- gen called ozone. This creates a smell – it’s the electric, model train smell. You may also encounter this smell from an electric drill or other electric motor with brushes if it doesn’t have a fan to blow away the smell. In an electrical fire scenario, this “electric motor” smell is followed quickly (or sometimes preceded by) the smell of hot or burning plastic, rubber or insu- lation. Sometimes you may even hear electrical popping, arcing or sizzling. Do not ignore these signs or second guess yourself if that is what you smell or hear. If it’s a developing electrical fire, you may only have a few minutes to find and put out the fire before much worse things happen. Fire! My first inflight electrical fire was aboard my trusty 1959 Cessna 150. I was stationed at MacDill Air Force Base in Tampa while going through initial F-16 training and kept the plane at Peter O. Knight Airport across the bay. One sunny day I took it out for a couple laps around the patch. Just after liftoff, the reverse current relay light came on and I smelled both electrical smell and battery acid. My voltage regula- tor overheated, failed to regulate and allowed 1.21 gigawatts (thereabouts) into my battery, which caused it to “boil over.” I shut off the master, landed immediately and ran into the FBO for a bucket of water to rinse the battery box and belly. I also had an incident where a par- tially bare wire once arced against my pressurization controller in the Duke, causing the electric smell and burn- ing rubber. And there were a couple of incidents with a recirculating fan while on the ground in the MD-80, but nothing like my Northwest/Delta friend Bob Hoffman experienced. He was flying a B-757 en route from JFK to MCO. A recirculating fan overheated inf light causing an electrical fire that filled the cabin with smoke. Bob landed 12 minutes after the checklist began, with no damage and no injuries. Here are some other published reports of electrical incidents. Accidents and Incidents • NorthAmericanAviation,Command Module, Apollo 1 – an electrical short started a fire which was exagger- ated by an O2 saturated environment resulting in loss of the module and crew in just 17 seconds. • MD11 belonging to Swissair – crashed into the sea off Nova Scotia following an inflight electrical fire caused by the inflight entertainment system. • A321 operated by British Midland – during cruise in night IMC had an electrical malfunction accom- panied by intermittent loss of the display on both pilots’ EFIS and an uncommanded change to a left-wing low attitude. • A319 operated by British Airways, London Heathrow to Edinburgh – experienced an electrical malfunc- tion during a night pushback, which blanked the EFIS displays follow- ing the second engine start and      Short N Numbers  SkyALdigdhictHtaAwvikation May 2020 / TWIN & TURBINE • 29 


































































































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