The possibility of any airplane crash is ''very remote'' and the possibility of an airplane crash into water is ''even more remote,'' the Federal Aviation Administration (FAA) said in 1980 when asked to improve water safety equipment.
Nonetheless, since 1960 more than 40 passenger planes (an average of two a year) have crashed into water. One of the most recent - Air Florida's Flight 90 that plunged into the icy Potomac River Jan. 13 in Washington, D.C., with a loss of 78 lives - has renewed the controversial debate over airline safety.
The Aviation Consumer Action Project (ACAP), a group founded by consumer advocate Ralph Nader, called on the FAA this week to require all airlines to carry life vests that can be put on in no more than 15 seconds. Passenger planes now are allowed to fly as far as 50 miles from land with only floatable seat cushions.
''Floatable seat cushions are very dangerous and basically absurd,'' asserts Matthew Finucane, the director of ACAP. The Coast Guard does not approve these cushions for children and nonswimmers. To use one properly, a person must hold it across his chest while floating in the water on his back. Most airlines don't tell you this on the pocket safety card, nor do they tell you that some cushions lose their buoyancy after 10 minutes. Manufacturers of the floatable seat cushions say that providing more buoyancy would make the cushions flammable during fire conditions.
There were life vests aboard the fatal Air Florida flight. But the National Transportation Safety Board says these vests have not been upgraded since World War II, are too difficult to put on, and often are stored under seats that collapse on impact with water. The Air Line Pilots Association wants upgraded life vests to be placed in seat backs so they can be retrieved faster. That location, where vests could easily be seen by flight attendants, may also prevent pilferage - 600 life vests a month are stolen on some air carriers.
Life rafts offer the best way to keep a person out of water and maintain the body temperature essential to survival, according to Wayne E. Williams, director of the Institute for Survival Technology in Dania, Fla. But air carriers are allowed to fly as far as 162 miles from land without rafts. Some carriers, including Air Florida, want that limit extended to 400 miles because the added weight of rafts increases fuel costs.
Removal of four 42-person rafts from a 727-200 makes the plane 500 pounds lighter and results in savings of 10,000 gallons of fuel a year, the FAA says. Any modern aircraft, the agency says, can fly 162 miles to shore on a single engine.
But what happens if a raftless plane crashes in water - no matter how many engines are working?
''The majority of airline accidents have little to do with engine problems,'' Mr. Williams explains. ''They are caused by human error, weather-systems failures, and fuel contamination,'' he says.
Nearly all airline crashes in water are less than 162 miles out to sea. Ninety-five percent occur on landing and takeoff at the 200 US airports situated near large bodies of water, according to the Air Line Pilots Association. It estimates that on-board safety equipment could save lives in 70 percent of such accidents.
A life raft may not have saved lives in the Air Florida crash, but in two accidents - one near Los Angeles and one near San Francisco - life rafts have kept passengers afloat until rescuers reached them. In 1978, however, when a National Airlines plane that had removed its rafts only days before, went down near the Pensacola, Fla., airport, three people drowned in warm water because of inadequate water-safety equipment.
Under its current administrator, J. Lynn Helms, a Reagan appointee, the FAA has begun to reject proposed safety rules instead of adding to existing ones. Although a new life vest that is easy to don has been designed by Air Cruisers, an aerospace manufacturing company, airlines estimate that vests and rafts on all flights would cost $40 million to install. The safety measures would cost an additional $38 million in jet fuel due to increased weight.
The FAA is required by law to ensure the ''highest possible safety standards'' in the air.
In the meantime, the Aviation Consumer Action Project has asked the FAA to improve airline water safety equipment within six months. There is little chance of action that soon. Safety proposals written and submitted 10 years ago are still pending before the FAA.