Eddie sez:

There are many lessons from this mishap, most of them so obvious it is stunning they happened at all:
I understood all of this back then in 1982, even with just two years experience with jet throttles. Now, thirty years later, I am usually the oldest pilot in the cockpit. Whenever ever I hear one of the youngsters say "I don't think that's right," I immediately say, "explain." Maybe he or she sees something I don't. Sometimes the safest thing you can do on the ground is set the parking brake and think things through.
Everything here is from the references shown below, with a few comments in an alternate color.
Photo: Air Florida 90, from washingtonpost.com.
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Figure: Flight path and witness locations, from NTSB Aircraft Accident Report, Figure 1.
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[NTSB Aircraft Accident Report, AAR-82-8, §1.1]
The aircraft was deiced about 50 minutes prior to its eventual takeoff. The report, page 56, notes: "The Safety Board is concerned that pilots may erroneously believe that there is a positive protection provided for a period following the application of deicing/anti-icing solution which eliminates the need to closely monitor the aircraft for contaminants during ground and takeoff operations. The Safety Board concludes that the only way to assure that the deicing process has been effective and that the aircraft is clean of adhering ice, snow, or frost, is by observation by the flight crew just before takeoff roll." Of course we have made a lot of progress since this mishap, but don't think you can always use the holdover tables or that they remove the obligation for a pretakeoff contamination check.
More about this: Cold Weather Operations.
Boeing warns against the use of reverse thrust in this situation because of occurrences of takeoff pitch control anomalies with the B-737 after ground operation in freezing conditions. This warning was incorporated into Air Florida flight manuals.
The flight manual required the use of engine anti-ice under these circumstances and there were no restrictions against its use. Furthermore, there was no significant performance penalty for its use during takeoff and climb.
It appears the captain was attempting to use the jet blast from the aircraft in front of him to deice his airplane, varying his position in the taxiway to get various portions of his aircraft.
Figure: JT-8D Exhaust pattern, from NTSB Aircraft Accident Report, AAR-82-8, figure 7.
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Of course taxiing closely behind another aircraft in these conditions would have the opposite effect from what was intended. From page 61: "The Safety Board believes the heat of the exhaust gases may have turned snow, which otherwise might have blown off during takeoff, into a slushy mixture. The mixture then froze on the wing leading edges and the engine inlet nose cone. The flight manual states: "Maintain a greater distance than normal between airplanes when taxiing on ice or snow covered areas. Engine exhaust may form ice on the ramp and takeoff areas of the runway and blow snow and slush which freezes on surfaces it contacts.
Figure: Engine sensor locations, from NTSB Aircraft Accident Report, Figure 5.
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Post accident simulator tests led the investigators to conclude that the left engine Pt2 engine probe was blocked, causing the anomaly the first officer spotted.
Most of the engine instruments were damaged from the impact or the water, but simulator tests show the flight path could be approximated with an engine EPR setting of 1.70, versus the 2.04 target. Tests of the engine EPR system also showed that with a blocked Pt2 probe, the probe senses vent pressure and will indicate 2.04 EPR with the engine actually operating at 1.70. Had they activated the engine anti-ice system, they would have "immediately notice a substantial drop in the indicated EPR."
The aircraft pitched higher than normal during the rotation because of contamination on the wing.
Simulator tests verify that had they increased thrust at any point from after liftoff until about 15 seconds, they could have pulled out of the descent and continued the climb.
[NTSB Aircraft Accident Report, AAR-82-8, ¶2.3]
[NTSB Aircraft Accident Report, AAR-82-8, page ii.] The National Transportation Safety Board determines that the probable cause of this accident was the flightcrew's failure to use engine anti-ice during ground operation and takeoff, their decision to take off with snow/ice on the airfoil surfaces of the aircraft, and the captain’s failure to reject the takeoff during the early stage when his attention was called to anomalous engine instrument readings. Contributing to the accident were the prolonged ground delay between de-icing and the receipt of ATC takeoff clearance during which the airplane 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.
NTSB Aircraft Accident Report, AAR-82-8, Air Florida, Inc., Boeing 737-222, N62AF, Collision with 14th Street Bridge Near Washington National Airport, Washington, D.C., January 13, 1982
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