FORT WORTH, Texas (CNN) -- Regulators have largely ignored a series of dangerous incidents in which cockpit windshields in commercial airliners shattered in midflight, sometimes forcing emergency landings, according to an American Airlines pilots' group.
A pilot who spoke to CNN said the cockpit window on his plane two years ago "shattered like a spider web."
Since 2004, at least 10 windshields have had problems on Boeing 757s, mostly the result of wiring problems with windshield heaters that cause smoke to fill the cockpit and sometimes make those windshields crack, according to the National Transportation Safety Board. Four incidents have been on American Airlines planes, the NTSB says.
An American Airlines flight from San Juan, Puerto Rico, to Philadelphia, Pennsylvania, made an emergency landing January 30 after the cockpit filled with smoke.
The inner pane of the co-pilot's window shattered as the plane came in to land in Palm Beach, Florida. One of the crewmembers was injured by glass, and six passengers were treated for smoke inhalation.
Another pilot said he had a similar experience on a 757 more than two years ago but did not want to be identified for fear of retaliation. Watch a report on the pilots' claims »
"Our entire windshield shattered like a spider web, and at that point in time, my other pilot and I donned our smoke goggles and oxygen masks for fear that the pane on the window was going to fail," he said.
Members of the Allied Pilots Association, which represents American Airlines pilots, say the company and the FAA have known for four years of this problem and done nothing.
"In 2004, there were two 757 incidents," said Todd Wissing, a pilot and APA safety committee member. "The NTSB investigated and made safety recommendations to the FAA."
But he said those recommendations were not acted upon, and he charged that safety lapses are occurring because the FAA is too close to the airlines.
"We depend on the FAA to have oversight of our company's operation and, in fact, the whole operation," he said.
"And we're disappointed when we see evidence that they haven't."
The evidence they point to is a February 1 e-mail from an American Airlines executive saying the January incident was the first he knew of involving an "internal window pane failure." Read the whole e-mail »
"We should gather the FACTS of how many failures we had and in how many flights very quickly to counter the NTSB and give us and the FAA some ammo to counter this,'' Robert W. Reding, executive vice-president of operations at American, wrote in the e-mail in response to an alert by then-spokesman John Hotard entitled "PBI incident to be NTSB poster child."
But American Airlines spokesman Tim Wagner said the e-mail simply meant: "Let's get our facts together. We [American] believe this way and it appears the FAA believes this way too."
Wagner said the union is complaining publicly because it is in contract negotiations. The pilots say that safety should come first and that any repairs would probably be costly, so there is no financial incentive for them to blow the whistle.
He said it is still unclear whether windshield incidents before the January Palm Beach emergency were caused by the same problem with the windshield heater.
"American is intent on providing information to ensure that the precise cause of the incident, which may differ from other similar events on other 757s, can be addressed and remedied appropriately. When the FAA has determined a remedy, we will comply with its directive."
The FAA, only now, has issued a proposed airworthiness directive for inspection and corrections to windshield heaters, not just on 757s but also on Boeing 767s and 777s.
"We will work with the manufacturer to provide a solution for operators, if the existing solution is not adequate," the FAA said in a statement to CNN.
But the FAA did not address why it has taken this long to address the problem since Boeing flagged it as an issue as early as 2004, the first time the NTSB also took notice.
A safety recommendation sent by the NTSB to the FAA in September gives details of the problems, many linked to the wiring of the windshield heaters. The recommendation also mentions promises by Boeing to send out service bulletins and pledges by the FAA to make the Boeing suggestions mandatory.
But NTSB Chairman Mark Rosenker wrote, "The Safety Board is very concerned that the [directives] originally scheduled to be issued as early as September 2004 still have not been issued. The Board considers any kind of fire and/or smoke in the cockpit to be a serious issue that could affect other aircraft systems, lead to a loss of visibility, provide a distraction, or incapacitate the crew and possibly lead to an accident."
Boeing said it was looking in to the matter. "It sounds like a maintenance item," a spokeswoman said. Efforts by CNN to get additional clarity on Boeing's statement were unsuccessful.
Critics in Congress have claimed that the FAA is too cozy with the industry and too confrontational with the NTSB.
The latest concerns about planes follow a CNN report last month that an FAA supervisor allowed Southwest Airlines to postpone required safety inspections. After that report, Rep. James Oberstar, D-Minnesota, questioned whether FAA had changed from a watchdog to a lapdog.
He said there was "a pendulum swing away from vigorous enforcement of regulatory compliance, toward a carrier-friendly, cozy relationship with the airlines."
Oberstar is holding a hearing on FAA oversight Thursday. E-mail to a friend
CNN's Todd Schwarzschild contributed to this report.