A cockpit blaze aboard a United Airlines jet last month revived a long-running debate over the dangers of potential windshield electrical fires on hundreds of Boeing aircraft.
But now, the incident also has focused attention on a related safety issue: Pilot complaints that emergency cockpit-oxygen systems on many of the same planes aren’t adequate to cope with such hazards.
Starting nearly three years ago, some pilot union leaders have complained that on certain Boeing 757 and 767 aircraft, the hoses for such oxygen systems aren’t long enough to allow pilots to keep the masks on while they retrieve the fire-extinguisher stored at the rear of the cockpit. The hose “may restrict movement to parts of the cockpit where the emergency equipment is stored,” according to a safety alert issued by the Air Line Pilots Association in September 2007. But “removing the mask in a toxic, smoke-filled environment puts the pilot at risk.”
In the fall of 2008, Federal Aviation Administration lawyers supported some of the union’s concerns. An internal agency memo concluded that at least one pilot must be able to reach the cockpit fire extinguisher without removing an oxygen mask.
A spokeswoman for The Federal Aviation Administration said last week that the agency is “looking into the issue” of longer hoses, but it has some concerns about pilots possibly getting distracted or even tangled up if the equipment is modified.
The hose issue was highlighted by the May 16 cockpit fire aboard the United Boeing 757, en route from New York to Los Angeles, which made an emergency diversion to Dulles International Airport near Washington. While cruising at 36,000 feet about 30 minutes into the flight, the captain’s lower front windshield began to smoke. The plane landed safely and none of the 112 people aboard sustained injuries. But investigators have said that flames shot out from the windshield, and the fire was serious enough that the crew eventually had to use two onboard fire extinguishers to put it out.
When one of the pilots attempted to reach the extinguisher stored in the cockpit while the aircraft was airborne, according to one person briefed on the details of the incident, his oxygen mask and smoke goggles were ripped off his face due to the length of the hose attachment
Over the weekend, a Boeing Co. spokesman didn’t have any comment on the matter.
While government and industry officials consider the design of oxygen hoses, underlying windshield hazards remain in the spotlight.
Fire dangers posed by defective electrical connections used on the windshield heating elements of more than 1,000 Boeing 757, 767 and 777 planes have been well documented. From the beginning of 2001 through April 2008, Boeing reported 29 separate incidents world-wide involving windshield smoke or fire. The manufacturer has issued a series of service bulletins urging airlines to ramp up inspections. The most recent revision, released at the end of March, broadens the portions of windshields subject to regular checks. If certain types of damage are detected, Boeing urges replacement of suspect parts or even entire windshields.
The National Transportation Safety Board continues to criticize FAA officials for moving too slowly to mandate precautionary replacement of suspect parts.
In March 2008, the FAA piggy backed on Boeing’s recommended maintenance moves and proposed to mandate stepped-up inspections covering more than 1,200 planes registered in the U.S. Hundreds of additional aircraft would be affected by foreign regulators adopting the U.S. agency’s standards.
Prompted by the United emergency landing, the FAA is now accelerating work on a final safety mandate covering windshields. But it’s not clear whether the FAA ultimately will expand its previous criteria calling for replacement of parts or windshields that show evidence of heat damage or other electrical defects.
With regulators poised to order greater precautions, a number of carriers are taking voluntary steps to reduce windshield smoke and fire hazards
AMR Corp.’s American Airlines, on its own, has replaced 85% of the windshields on its 757 and 767 fleets. A spokesman said Friday that by the spring of 2011, all of them will be replaced with product purchased from a different supplier.
Current precautionary inspection intervals vary at other big carriers, though some have been shortened as a result of the United fire.
US Airways had been conducting routine inspections of Boeing 757 windshields every 1,000 flight hours. Now, according to a spokesman, that has been reduced to 500-hour intervals, which is the timetable proposed by the FAA last year. The spokesman said the airline hasn’t found any damage or improperly installed connections between power wires and heating elements.
Delta Air Lines Inc. initially opted for inspections every 3,000 hours, and a spokesman said Friday that hasn’t changed.
A spokeswoman for UAL Corp.’s United Airlines said last week that the carrier complies with all of Boeing’s recommendations and “has implemented enhancements to our maintenance program” in the wake of the Dulles incident. But over the weekend, she declined to elaborate.
