The NTSB is investigating crew-duty times, crew performance, crew training and aircraft maintenance issues in connection with the February 20 accident in which a Skylink Jets Learjet 25B, N24RZ, overran the runway and hit a building while landing at Fort Lauderdale Executive Airport, Fla. Of the four people on board, only the two pilots received injuries. The twinjet had departed from San Juan, Puerto Rico, about 90 minutes before the accident. ATC personnel said that during the approach the crew reported low fuel and requested priority handling. The airplane touched down about midway down the 6,000-foot runway, according to controllers. The pilots said there were problems with the hydraulic system, including complete loss of brakes, and they also said that the emergency drag chute failed to deploy. The crew did not attempt to use the emergency brake system, according to the NTSB.