King Air C90 E90
Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Flight Instructor
Flight Crew Last 90 Days 30; Flight Crew Total 4200; Flight Crew Type 110
Troubleshooting; Workload; Physiological - Other; Time Pressure
Aircraft Equipment Problem Critical; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Flight Crew FLC complied w / Automation / Advisory; Flight Crew Took Evasive Action; Flight Crew Landed in Emergency Condition; General Maintenance Action
Aircraft; Procedure
I was enroute to pick up a passenger and bring them back to home base. It was a short flight so I cruised at 13;000 FT. A few moments before top of descent I noticed a light haze in the cockpit and an odd smell. Not super strong; not acrid; hard to describe but unpleasant and smelly. My eyes and lungs were slightly irritated but it was not as irritating as getting a blast of wood smoke in the face. The smoke/fumes were light gray/whitish maybe sort of purple. The smoke/fumes began to billow out of the copilot side upper wemac vent (maybe from other sources but none that I could determine). I donned my O2 mask (not quick-donning type); ran the emergency checklist; and dumped the cabin all while in the descent talking to ATC and getting vectored onto the approach. During this sequence I discovered that my O2 mask was not delivering O2 and the autopilot was malfunctioning due to an electric trim issue. I began hand-flying the aircraft at this point. The arrival airport was IFR. During the descent; with the power pulled back; the smoke/fumes were improving/dissipating/not continuing. The smoke/fumes at no time obscured my vision of the instrument panel; nor inhibited me from seeing outside (still IMC at this point). The engine instruments were indicating within normal parameters; no circuit breakers popped; and I did not lose any systems (avionics etc). The landing was uneventful. I taxied off the runway and shutdown at the nearest parking spot. Upon exiting the aircraft I noticed an intense stink; like burnt oil/rubber; in the aircraft vicinity. A visual walk around of the aircraft did not reveal any other information (no oil streaks; no soot; just smell). A maintenance inspection revealed that 2 of the oxygen masks onboard were plugged and that greasing the electric trim motor resolved the autopilot issue. Maintenance is still trying to isolate the source of the smoke/fumes and think that it is a problem with an oil seal in the right engine. About 90 flight hours before this occurrence; the cold section of the right engine was repaired due to excessive vibration caused by a cracked compressor blade. The engine has around 350 hours before overhaul. In hindsight; I would definitely have declared an emergency. I was very busy during the descent and the situation seemed to be improving. The airspace was not busy and it sounded like I was number one on approach. I was also too busy to locate and test another O2 mask; as I was hand-flying the aircraft. The O2 bottle was indicating slightly less than full upon departure. I regularly check the O2 masks and had not checked them prior to this particular flight. The aircraft checklist does not specify checking the masks before flight. The O2 masks on this aircraft are continuous flow type without any communication capability and not quick-donning; which strikes me as potential safety concern and a pain in the butt for single pilot operations at altitude with a smoke/fume event.
A BE9L developed cockpit smoke and fumes during cruise flight so the pilot descended; depressurized; and while donning the O2 mask found it inoperable. Because the autopilot malfunctioned; the pilot was hand flying the IMC approach while troubleshooting the smoke/fume problem.