Smoke in a plane's cockpit from electrical or other failures is reported an average of four times each month, a USA TODAY analysis finds.
Smoke is an immediate safety concern anywhere in an aircraft and an even greater concern in the cockpit where it could cripple vital systems or obscure navigational instruments.
USA TODAY's analysis, which included data from the Federal Aviation Administration and National Transportation Safety Board, shows more than 650 reports of smoke in jet-plane cockpits since Jan. 1, 2000.
Most involve airline jets; some were corporate jets.
The 650 reports may seem small compared to more than 800,000 flights flown monthly by U.S. airlines. The number of incidents, though, is underreported to the FAA, according to past studies of smoke in aircraft, and a 2004 FAA advisory warns that a small in-flight fire can lead to catastrophe.
In-flight fires left unattended "may lead to catastrophic failure and have resulted in the complete loss of airplanes," the FAA warned. A flight crew "may have as few as 15-20 minutes to get an aircraft on the ground if the crew allows a hidden fire to progress without intervention."
In the 650 reports, there were at least 242 unscheduled or emergency landings, nine emergency descents below 10,000 feet and 16 aborted takeoffs.
USA TODAY's findings show that a system to remove cockpit smoke — which the FAA doesn't require — should be required, says former NTSB chairman Jim Hall.
The need for such systems has "always been a no-brainer," Hall says. "The nearest fire exit doesn't work well at 30,000 feet."
While USA TODAY found hundreds of smoke-in-cockpit incidents, including some involving heavy or dense smoke, the FAA says in a written statement it is aware of no events during the past 10 years of "dense, continuous smoke" in the cockpit. The agency says its data and NTSB data show "there is no safety benefit" to require airlines to install systems to remove cockpit smoke.
A June report by the Government Accountability Office said the FAA receives "several" reports annually of smoke in cockpits, but the FAA and NTSB did not identify any accident or incidents from 2002 through 2012 that involved "dense, continuous smoke."
The report added, however, that the FAA and NTSB have no definition of "dense, continuous smoke," and neither agency tracks such incidents.
The GAO report did not mention hundreds of smoke-in-the-cockpit incidents found by USA TODAY in the FAA's service-difficulty report database.
It also didn't mention that, in 2006, Jim Ballough, the FAA's director of flight standards that year, said "numerous events" of smoke or fumes in the cockpit are "not being reported," or, in a 2000 study for the Society of Automotive Engineers, now SAE International, airline pilot Jim Shaw said the FAA database "has many limitations" and under-reports "significant events."
The GAO report did not mention that pilots reported cockpit smoke before all 110 aboard were killed in a May 1996 crash of a ValuJet DC-9 in the Everglades in 1996 and before all 229 aboard were killed in aSeptember 1998 crash of a Swissair MD-11 into water near Halifax, Canada.
The report also did not mention two UPS cargo plane accidents in 2006 and 2010.
In the 2006 accident in Philadelphia, cockpit smoke "became so thick that the two pilots could not see each other before evacuating the airplane."