Page:CAB Accident Report, American Airlines Flight 383.pdf/10

– 9 – Runway 18 at Cincinnati is equipped with a transmissometer adjacent to the ILS touchdown point on the approach end of the runway. Examination of the recorder trace revealed that at approximately 1903 a sharp drop in the transmissivity of the atmosphere occurred which reduced runway visibility to 1-1/8 miles. Almost immediately thereafter the transmissivity increased showing runway visibilities in excess of two miles.

Prior to departure from LaGuardia the captain of Flight 383 was provided with a dispatch packet which included the company forecast for the Cincinnati terminal for the period 1600-2000. This forecast called for 1,200 feet broken, 3,500 feet overcast, visibility 4 miles, light rain, fog, variable to 1,000 feet overcast, visibility 2 miles, thunderstorm, moderate rain showers.

A weather information display board is also installed at the LaGuardia American Airlines Operations office. Company employees observed Captain Teelin briefing himself at this board at approximately 1600.

The American Airlines' Briefing Forecaster on duty in the New York Flight Dispatch office at Kennedy International Airport stated that a "pilot" called at approximately 1610 and advised that he was going to Cincinnati and requested weather information. The caller did not identify himself by name or flight number. The forecaster stated that he briefed the pilot to the effect that 35,000 feet would be a good cruising altitude over the intended route and that the flight should be on top of all weather until descent into the Cincinnati area. He also stated that a route over Charleston, West Virginia, should put the flight south of all thunderstorm activity except for what he would find in the Cincinnati area on arrival.

Following the accident a special study was conducted by the USWB in order to determine the possibility of any vertical and/or horizontal wind shear in the Cincinnati area. The study revealed a maximum recorded gustiness of 16-17 knots and a wind shear of about 0.6 knots per hundred feet in the area.

Additionally, the study indicated a headwind component change on the aircraft of approximately five knots per minute during the last minute of flight.

1.8 Aids to Navigation

All components of the ILS serving runway 18, the Cincinnati VOR, and the facility radar were in operation at the time of the accident. These navaids were flight checked shortly after the accident and were found to be operating within prescribed tolerances.

1.9 Communications

The air traffic services provided to Flight 383 from LaGuardia to Cincinnati were examined and found to be in accordance with standard Air Traffic Control (ATC) practices and procedures.

With respect to the flight's arrival in the Cincinnati area it was noted that AA 383 requested a "control VFR" and was cleared by Approach Control for a "visual approach" to runway 18.

It is to be noted that there is no specific definition of the term "control VFR"