Understanding Air Safety in the Jet Age/Air Florida Flight 90
On a freezing night in Washington in 1982 Captain Larry M. Wheaton, aged 34, climbed into the cockpit of Air Florida Flight 90. He was an experienced pilot with 8,300 total flight hours, with 2,322 hours of commercial jet experience, all logged at Air Florida. In the seat next to him was first officer, Roger A. Pettit, aged 31, a former US Air Force fighter pilot, and instructor, with 3,353 flight hours. Wheaton was described by fellow pilots as a quiet person, with good operational skills and knowledge, who had operated well in high-workload flying situations. His leadership style was described as similar to those of other pilots. However, on 8 May 1980 he was suspended after failing a Boeing 737 company line check and was found to be unsatisfactory in several areas including adherence to regulations, checklist usage, flight procedures such as departures and cruise control, and approaches and landings. He resumed his duties after passing a retest on 27 August 1980. On April 24, 1981 he received another unsatisfactory grade, this time on the company recurrent proficiency check, when he showed deficiencies in memory items, knowledge of aircraft systems, and aircraft limitations. Three days later, he satisfactorily passed a proficiency recheck. Failure to follow procedures was a critical factor in what was to come.
In contrast, there were no concerns about Pettit. He was described by friends and pilots as a witty, bright, outgoing individual with an excellent command of physical and mental skills in aircraft piloting. Those who had flown with him during stressful flight operations said that during those times, he remained the same witty, sharp individual, "who knew his limitations." Several persons said that he was the type of pilot who would not hesitate to speak up if he knew something specific was wrong with flight operations.
The flight was scheduled to depart on 13 January 1982 from Washington National Airport (now Ronald Reagan Washington National Airport) to Fort Lauderdale–Hollywood International Airport with an intermediate stopover at Tampa International Airport. That morning the airport was closed by a heavy snowstorm that produced 6.5 inches of snow. It reopened at noon under marginal conditions as the snowfall began to slacken. Nearly two hours late, as the plane readied for departure, a moderate snowfall continued and the air temperature was well below freezing.
In these conditions, icing was the main concern. Multiple critical instruments can be affected by ice, and ice on the wings can quite literally stop a plane flying by changing the shape of the wings. Every airline and airport has procedures to deal with ice on the ground and in the air. Unfortunately the captain of this plane wasn't great at following procedures. At the gate, Flight 90 was de-iced with a mixture of heated water and monopropylene glycol by American Airlines, under a ground-service agreement with Air Florida. That agreement specified that covers for the pitot tubes, static ports, and engine inlets had to be used, but the American Airlines employees did not comply with those rules. One de-icing vehicle was used by two different operators, who chose widely different mixture percentages to de-ice the left and right sides of the aircraft. Subsequent testing of the de-icing truck showed that "the mixture dispensed differed substantially from the mixture selected" (18% actual vs. 30% selected). The inaccurate mixture was the result of the replacement of the standard nozzle, "...which is specially modified and calibrated, with a non-modified, commercially available nozzle." The operator had no means to determine if the proportioning valves were operating properly because no "mix monitor" was installed on the nozzle. Or put more simply, the de-icing was ineffective due to multiple errors.
The plane had trouble leaving the gate when the ground-services tow motor could not get traction on the ice. For roughly 30 to 90 seconds, the crew attempted to back away from the gate using the reverse thrust of the engines which proved futile. Boeing operations bulletins had warned against using reverse thrust in those kinds of conditions. Eventually, a tug ground unit properly equipped with snow chains was used to push the aircraft back from the gate. After leaving the gate, the aircraft waited in a taxi line with many other aircraft for 49 minutes before reaching the take-off runway. The pilot apparently decided not to return to the gate for reapplication of de-icing, fearing that the flight's departure would be even further delayed. More snow and ice accumulated on the wings during that period, and the crew was aware of that fact when they decided to make the take-off. Heavy snow was still falling during their take-off roll just before 4:00 pm.
The crew then ran through the take-off checklist
Captain Pitot heat?First Officer On.
Captain Engine anti-ice?
First Officer Off.
Despite the icing condition the crew had failed to activate the engine anti-ice systems, which caused the engine pressure ratio thrust indicators to provide false readings. The correct engine power setting for the temperature and airport altitude of Washington National at the time was 2.04 EPR, but it was later determined from analysis of the engine noise recorded on the cockpit voice recorder that the actual power output corresponded with an engine pressure ratio of only 1.70.
Neither pilot had much experience flying in snowy, cold weather. The captain had made only eight take-offs or landings in snowy conditions on the 737, and the first officer had flown in snow only twice.
Adding to the plane's troubles was the pilots' decision to manoeuvre closely behind a DC-9 that was taxiing just ahead of them prior to take-off, due to their mistaken belief that the warmth from the DC-9's engines would melt the snow and ice that had accumulated on Flight 90's wings. This action, which went specifically against flight-manual recommendations for an icing situation, actually contributed to icing on the 737. The exhaust gases from the other aircraft melted the snow on the wings, but during take-off, instead of falling off the plane, this slush mixture froze on the wings' leading edges and the engine inlet nose cone.
As the take-off roll began, the first officer noted several times to the captain that the instrument panel readings he was seeing did not seem to reflect reality (he was referring to the fact that the plane did not appear to have developed as much power as it needed for take-off, despite the instruments indicating otherwise). The captain dismissed these concerns and let the take-off proceed. Investigators determined that plenty of time and space on the runway remained for the captain to have aborted the take-off, and criticised his refusal to listen to his first officer, who was correct that the instrument panel readings were wrong. The pilot was told not to delay because another aircraft was 2.5 miles out on final approach to the same runway. All the pieces were in place for a disaster. The plane began to accelerate down the runway.
15:59:32 First Officer Okay, your throttles.15:59:35 [SOUND OF ENGINE SPOOLUP]
15:59:49 First Officer Holler if you need the wipers.
15:59:51 First Officer It's spooled. Really cold here, real cold.
15:59:58 Captain God, look at that thing. That don't seem right, does it? Ah, that's not right.
16:00:09 First Officer Yes it is, there's eighty.
16:00:10 Captain Naw, I don't think that's right. Ah, maybe it is.
16:00:21 First Officer Hundred and twenty.
16:00:23 Captain I don't know.
16:00:31 First Officer V1. Easy, V2.
As the plane became briefly airborne, the voice recorder picked up the following from the cockpit, with the sound of the stick-shaker (a device that warns that the plane is in danger of stalling) in the background:
16:00:39 [SOUND OF STICKSHAKER STARTS AND CONTINUES UNTIL IMPACT]16:00:41 TWR Palm 90 contact departure control.
16:00:45 First Officer Forward, forward, easy. We only want five hundred.
16:00:48 First Officer Come on forward....forward, just barely climb.
16:00:59 First Officer Stalling, we're falling!
16:01:00 Captain Larry, we're going down, Larry....
16:01:01 First Officer I know!
16:01:01 [SOUND OF IMPACT]
The aircraft travelled almost half a mile farther down the runway than is customary before lift-off was accomplished. Survivors of the crash indicated the trip over the runway was extremely rough, with survivor Joe Stiley – a businessman and private pilot – saying that he believed that they would not get airborne and would "fall off the end of the runway". When the plane became airborne, Stiley told his co-worker (and survivor) Nikki Felch to assume the crash position, with some nearby passengers following their example.
Although the 737 did manage to become airborne, it attained a maximum altitude of just 350 ft before it began losing altitude. Recorders later indicated that the aircraft was airborne for just 30 seconds. It then fell from the sky crashing into the 14th Street Bridge across the Potomac River, less than a mile from the end of the runway. The plane hit six cars and a truck on the bridge, and tore away the bridge's rail and wall. The aircraft then plunged into the freezing Potomac River. It fell between two of the three spans of the bridge, between the I-395 northbound span (the Rochambeau Bridge) and the HOV north- and southbound spans, about 200 ft offshore. All but the tail section quickly became submerged.
Of the people on board all but five died including both pilots. Four motorists on the bridge were also killed. Clinging to the tail section of the broken airliner in the ice-choked Potomac River were flight attendant Kelly Duncan and four passengers: Patricia "Nikki" Felch, Joe Stiley, Arland D. Williams Jr. (strapped and tangled in his seat), and Priscilla Tirado. Duncan inflated the only flotation device they could find, and passed it to the severely injured Felch. Passenger Bert Hamilton, who was floating in the water nearby, was the first to be pulled from the water. Without rapid rescue, their lives would be measured in minutes.
Many federal offices in downtown Washington had closed early that day in response to quickly developing blizzard conditions. Thus, a massive backup of traffic existed on almost all of the city's roads, making reaching the crash site by ambulances very difficult. The Coast Guard's harbour tugboat Capstan (WYTL 65601) and its crew were based nearby; their duties include ice breaking and responding to water rescues. The Capstan was considerably farther downriver on another search-and-rescue mission. Emergency ground response was greatly hampered by ice-covered roads and gridlocked traffic, ambulances dispatched at 4:07 pm took 20 minutes to reach the scene of the crash. Ambulances attempting to reach the scene were even driven down the sidewalk in front of the White House. Rescuers who reached the site were unable to assist survivors in the water because they did not have adequate equipment to reach them. Below-freezing waters and heavy ice made swimming out to them impossible. Multiple attempts to throw a makeshift lifeline (made out of belts and any other things available that could be tied together) out to the survivors proved ineffective. The rescue attempts by emergency officials and witnesses were recorded and broadcast live by area news reporters, and as the accident occurred in the nation's capital, large numbers of media personnel were on hand to provide quick and extensive coverage.
Luckily for the survivors there were heroes nearby. Roger Olian, a sheet-metal foreman at St. Elizabeth's Hospital, a Washington psychiatric hospital, was on his way home across the 14th Street Bridge in his truck when he heard a man yelling that an aircraft was in the water. He was the first to jump into the water to attempt to reach the survivors. At the same time, several military personnel from the Pentagon—Steve Raynes, Aldo De La Cruz, and Steve Bell—ran down to the water's edge to help Olian.
He only traveled a few yards and came back, ice sticking to his body. We asked him to not try again, but he insisted. Someone grabbed some short rope and battery cables and he went out again, maybe only going 30 feet. We pulled him back. Someone had backed up their jeep and we picked him up and put him in there. All anyone could do was tell the survivors was to hold on not to give up hope. There were a few pieces of the plane on shore that were smoldering and you could hear the screams of the survivors. More people arrived near the shore from the bridge, but nobody could do anything. The ice was broken up and there was no way to walk out there. It was so eerie, an entire plane vanished except for a tail section, the survivors, and a few pieces of plane debris. The smell of jet fuel was everywhere, and you could smell it on your clothes. The snow on the banks was easily two feet high and your legs and feet would fall deep into it every time you moved from the water.
At this point, flight controllers were aware only that the plane had disappeared from radar and did not respond to radio calls, but had no idea of either what had happened or the plane's location. About 20 minutes after the crash a United States Park Police Bell 206L-1 Long Ranger helicopter based at the "Eagles Nest" at Anacostia Park in Washington and manned by pilot Donald W. Usher and paramedic Melvin E. Windsor, arrived and began attempting to airlift the survivors to shore. At great risk to themselves, the crew worked close to the water's surface, at one time coming so close to the ice-clogged river that the helicopter's skids dipped beneath the surface.
The helicopter crew lowered a line to survivors to tow them to shore. First to receive the line was Bert Hamilton, who was treading water about 10 ft (3 m) from the plane's floating tail. The pilot pulled him across the ice to shore, while avoiding the sides of the bridge. By then, some fire/rescue personnel had arrived to join the military personnel and civilians who pulled Hamilton (and the next/last three survivors) from the water's edge up to waiting ambulances. The helicopter returned to the aircraft's tail, and this time Arland D. Williams Jr. (sometimes referred to as "the sixth passenger") caught the line. Williams, not able to unstrap himself from the wreckage, passed the line to flight attendant Kelly Duncan, who was towed to shore. On its third trip back to the wreckage, the helicopter lowered two lifelines, fearing that the remaining survivors had only a few minutes before succumbing to hypothermia. Williams, still strapped into the wreckage, passed one line to Joe Stiley, who was holding on to a panic-stricken and blinded (from jet fuel) Priscilla Tirado, who had lost her husband and baby. Stiley's co-worker, Nikki Felch, took the second line. As the helicopter pulled the three through the water and blocks of ice toward shore, both Tirado and Felch lost their grips and fell back into the water.
Priscilla Tirado was too weak to grab the line when the helicopter returned to her. A watching bystander, Congressional Budget Office assistant Lenny Skutnik, stripped off his coat and boots, and in short sleeves, dove into the icy water and swam out to successfully pull her to shore. The helicopter then proceeded to where Felch had fallen, and paramedic Gene Windsor stepped out onto the helicopter skid and grabbed her by the clothing to lift her onto the skid with him, bringing her to shore. When the helicopter crew returned for Williams, the wreckage he was strapped into had rolled slightly, submerging him; according to the coroner Williams was the only passenger to die by drowning. His body and those of the other occupants were later recovered.
The subsequent investigation found that the 737 had broken into several large pieces upon impact - the nose and cockpit section, the cabin up to the wing attachment point, the cabin from behind the wings to the rear airstairs, and the empennage. Although actual impact speeds were low and well within survivability limits, the structural breakup of the fuselage and exposure to freezing water nonetheless proved fatal for all persons aboard the plane except those seated in the tail section. The National Transportation Safety Board concluded that the accident was not survivable. Determining the position of the rudder, slats, elevators, and ailerons was not possible due to impact damage and the majority of the flight control system having been destroyed. The National Transportation Safety Board determined that the probable cause of the crash included the flight crew's failure to enforce a sterile cockpit during the final preflight checklist procedure. The engines' anti-ice heaters were not engaged during the ground operation and take-off. The decision to take off with snow/ice on the airfoil surfaces of the aircraft, and the captain's failure to reject the take-off during the early stage when his attention was called to anomalous engine instrument readings also were erroneous.
The NTSB further stated:
"Contributing to the accident were the prolonged ground delay between de-icing and the receipt of ATC take-off clearance during which the aircraft was exposed to continual precipitation, the known inherent pitch up characteristics of the B-737 aircraft when the leading edge is contaminated with even small amounts of snow or ice, and the limited experience of the flight crew in jet transport winter operations.