Delta captains who had flown recently with the first officer describedhimas 'an above average first officer. They stated that he had excellent knowledgejbf‘ the L-1011. For 2 years, beginning in September 1977, the first officer had worked'With "the
company's L—lOll ground school instructors staff to revise completely Books I and II of ' the Delta Air Lines L—1011 Pilot Operating Manual. In October 1973, the FAA de51gnated
the first officer as a line and proficiency check airman in the L-1011 airplane.
Fellow company cockpit personnel described the second officer as observant, alert, and professional. He monitored the operation of the airplane and called attention to items he thought required it. He had a good knowledge of the airplane. He had served as second officer instructor and check airman on the Boeing B-727 airplane. FAA records for eight route inspections since April 1981 indicated satisfactory performance.
Interviews with the three air traffic control (ATCIcontrollersJ’whou'. had provided air traffic services to flight 191, during its descent and final approachfto DFW Airport did not disclose anything either remarkable or out of the ordinary. The three controllers, two radar controllers, and local controller in the airport tower were full performance level (FPL) controllers and were fully qualified to staff their respective positions. (See appendix B.) Only one controller, the AR—l controller had worked any overtime during the 2 weeks preceding the accident. He had worked overtime on"July 30, 1986, and Was off duty the following day. '
1.6 Airplane Information .0
The airplane, a Lockheed L-1011-385-1, N726DA, was owned and operated by Delta. (See appendix C.) The airplane’s maximum takeoff and landing gross weightswere 430,000 pounds and 348,000 pounds, respectivelyn Based on the company'swfinal vae'ight data record contained in flight 191's dispatch documents, its estimated landing weight and center of gravity for landing at the DFW Airport were 324,800 pounds and 21.8 percent MAC (mean aerodynamic chord). The forward and aft center of gravity limits for landing were 17.1 percent MAC and 32.4 percent MAC. Based on the landing weight and with the flaps set at 33°, the calculated approach speed was 137 KIAS. 1_2/ The maximum ' allowable tailwind for takeoff and landing was 10 knots, and the maximum demOnstrated landing crosswind was 35 knots. ‘ ’ "
Flight 191 had about 28,000 pounds of fuel when it began its approach. According to the flight plan, 12,300 pounds plus the required 11,000—pound reserve were required for the flight to the alternate airport, San Antonio, Texas, leaving 4,700pounds of erl for maneuvering in the DFW Airport area. At 3,000 feet, gear andelaps 'up, 4,700 pounds of fuel would have permitted the flight to hold about 20 minutes before departing for San Antonio. ‘
I N726DA was equipped with a Bendix model RDR-lF monochromatic weather radar system. The system loperates on X-band frequency at a 3.2 cm wavelength. y The system is designed to display targets at three range selections--50, 150, and 300'nauticai miles (nmi)--and to display weather in two modes——normal and contour. Initheflnormal mode, any precipitation return exceeding a radar reflectivity of 20 dBZ 1_3/,is displayed as a luminescent green area on the dark background of the plan position indicator .(PPI).'.~The stronger the reflectivity of the precipitation return, the stronger the return displayed on the PPI will be. When the radar system is placed in contour mode, the contour circuitry,
ETAbbiaaéhj‘oi'FéféraEe speed (Vref), is a speed equal to 1.3 times the stall speed-in a _ particular airplane configuration. ' ' ' " _l_3/ dBZ: A measurement of radar reflectivity expressed in decibels.
