Potential In-Flight Fire Events Occur Daily; Many in Inaccessible Areas

Air Safety Week, April 24, 2000

He dismissed the fear often expressed by airline industry officials that the water mist would foul the functioning of vital electronics. On the Shadwell, Lawson said, "A 30-minute exposure posed little or no hazard to energized switchboards, motor controllers or electric motors."

Adams believes the existing potable water supplies on an airliner may be more than adequate for a water-mist fire suppression system to protect the presently unprotected cabin area. A full-up system of detection and suppression would weigh on the order of 200 pounds. The Navy will be testing a prototype water-mist system in the cabin of a retired B737 early next month (system performance will be duly reported in this publication).

Better access. Adams pointed out that fires can propagate behind panels. Indeed, one such fire occurred behind the flight engineer's panel on a Delta Airlines [DAL] L-1011 enroute from Hawaii to California in late 1998 (see ASW, July 12, 1999). The flight crew could see the flames behind the narrow seam of the metal cover but could not squirt fire-suppressing chemical from the hand extinguisher into the interior. Adams believes that access ports to insert extinguishers could be installed, enabling crews to apply extinguishing agent without having to waste time with screwdrivers or fire axes opening panels.

The need for such emergency fire extinguishing ports is growing, Adams maintained. More electrical components are migrating into the cabin area "Little closets with avionics stuffed in them," he said. Adams recalled the recent case of a 767 on a Trans-Atlantic flight where the electronics in one of these closets overheated, and the crew was forced to divert to a precautionary landing in Ireland.

Better procedures. According to Holoviak, instances of in-flight smoke and fire need to be treated "as equal to the complete loss of one engine on a twinjet." The procedures, he said, should be designed to "get the aircraft pointed in the right direction immediately" for landing.

Emergency checklists, Adams declared, "should be designed to relieve the crew of troubleshooting, focus on emergency diversion, depower to essential items, and land as soon as possible." As an example, the first three items on the Delta 767-400 smoke/fire emergency checklist consist of: (1) don masks, (2) establish communications, (3) begin the divert.

With respect to depowering flight essential systems, Bill Sell, an engineer with German circuit breaker (CB) manufacturer E-T-A Elektrotechnische Apparate GmbH, suggested a simple system of standardized color-coding. The breakers for critical circuits, he suggested, could be colored red. "If it pops, you know immediately a flight essential circuit is affected," he said.

"You could put a colored cap over the button, or use a simple insert, e.g., color code the rating label" on the CB, Sell explained. In other words, the red-coded CBs would help pilots to "sweat the red stuff," as it were. The color-coding, Sell believes, would be a boon to pilots, who are "under pressure anyway" when the CBs start popping.