Boeing 737 jetliner pilots should be required to take new safety precautions when taking off in icy weather, the National Transportation Safety Board recommended yesterday.
The recommendation, one of 11 the board approved yesterday in wrapping up its investigation into why an Air Florida 737 struck the 14th Street bridge during a snowstorm last Jan. 13, is intended to guard against control problems that 737s have experienced in icy weather.
Pilots should apply all or some of the following steps, the board said: Use wing anti-ice devices while the plane is on the ground to melt any deposits before take-off, increase runway speed beyond current standard levels and employ different wing flap settings to provide extra lift.
On Tuesday, the board ruled that pilot error, including a decision to take off despite the presence of lift-reducing ice or snow on the wings, was the prime cause of the accident, which took 78 lives.
But it cited as a contributing factor the "known inherent . . . characteristics" of the 737, the world's third most common jetliner, to "pitch up" or rise sharply at the nose if "even small amounts of snow or ice" are present on the wings' leading edges.
The board's recommendations, issued under its mandate to prevent accidents, were addressed to the Federal Aviation Administration, which yesterday declined comment pending detailed study. By law, the FAA is required to respond to, but not necessarily adopt, the recommendations.
The board also called on the FAA to:
* Meter traffic more carefully to "minimize airport saturation and extensive traffic delays." The board has cited as a factor in the crash the 49-minute delay between the time ground crews deiced Air Florida Flight 90 and the time it took off, which allowed extra snow and ice to build up on the plane.
* Emphasize to tower controllers that arriving and departing planes using the same runway must be at least two miles apart. The FAA should also tighten procedures to assure that controller errors are reported and investigated, the board said.
The board concluded that a National Airport controller violated regulations by allowing an Eastern Airlines jet approaching from the south to touch down on the southern end of Runway 36 before the Air Florida jet lifted off from the northern end.
* Provide "essential equipment and increased personnel training" for water rescues around National Airport, which the FAA owns and operates, as well as "necessary funding for surrounding communities" that would send rescue units to respond to a crash.
National Airport spokesman Dave Hess said the airport already is acting to improve rescue capabilities. Since the crash, he said, the airport has received two new rescue boats and is expecting a third, has bought two helicopter nets for lifting survivors from the water, has installed direct telephone lines to D.C. police marine and helicopter units and is training a diving team.
In the past, the FAA has argued that it should not pay for heavy equipment that local jurisdictions may want to buy, such as helicopters and Hovercraft.
* Require that airports with flight paths over water have "adequate water rescue capabilities." Current rules do not require any preparation, though large airports or surrounding jurisdictions generally do have plans in place.
* Emphasize to airlines the importance of proper maintenance for ground equipment. The board ruled that a replacement nozzle on a deicing-fluid hose created a mixture more diluted than intended.
* Ensure that ground-service contractors understand maintenance procedures for planes they are working on and know who is in charge. The report found that American Airlines personnel who deiced the Air Florida jet on contract did a "deficient" job.
The proposed safety precautions for 737s at takeoff matched in part steps that Britain's Civil Aviation Authority had already taken for British-operated 737s. The CAA ordered "overspeed" and different flap settings earlier this year.
Shortly after the Jan. 13 crash, Air Florida also implemented steps for foul-weather takeoffs that effectively required higher speeds for its 737s. The airline has argued that uncontrollable "pitch-up" of the Boeing aircraft was the prime cause of the accident.
At least 23 incidents of 737s pitching up suddenly in icy flying conditions have been reported since 1968. Boeing has repeatedly advised airlines on how to counter it. Yesterday, Boeing spokesman Tom Cole noted that the company's advice has included overspeed.
In related developments yesterday, the Air Line Pilots Association (ALPA) contested the board's finding of pilot error.
Testifying during a joint hearing into bad-weather aviation accidents by two subcommittees of the House Science and Technology Committee, Jack D. Howell, executive central air safety chairman for ALPA, said he was "baffled by how the board could say that pilot error was the cause . . . When you say pilot error, period, full stop, then we don't benefit" from lessons the accident might offer, Howell said.
An ALPA official who took part in the board investigation, Jim McWilliams, added yesterday: "When you come out and say a pilot made an error but don't explain why he made an error, you haven't done one thing to relieve the safety problem."