Page:CAB Accident Report, Eastern Air Lines Flight 663.pdf/18

Rh was on a northeast heading at the time. The reduction in distance would be insignificant and reduce the required speed to approximately 400 knots to reach the indicated positions at 1825:21.

Even if the handoff location is considered to be a mile east of the JFK 160, degree radial, and the EAL 663 position a mile west of the place stated by the controllers, which certainly is the most optimistic and favorable condition possible in light of their testimony, it still would be necessary for EAL 663 to cover the distance of four miles in 51 seconds, or in other words, to proceed frost one point to the other at a groundspeed of 282 knots. This would be approximately 80 knots greater than the normal operating speed for the aircraft under the existing conditions. One flightpath for EAL 663 has been projected on the basis of the testimony of the PAA 212 captain, first officer, and RR-7 (center) controller. This flight. path was plotted with that developed for PAA 212 and is pictorially displayed on Attachment #4. The following factors were used in the projection of the EAL 663 flightpath: The captain of PAL 212 estimated that 40 to 45 seconds elapsed from the start of EAL 663's turn toward them until it passed them. He also estimated that had the traffic in sight for a minute and 15 to 20 seconds from the first observation to the time of passing. PAA 212 acknowledged the traffic call at 1825:00, 1:26 minutes prior to the passing. The PAA first officer estimated the elapsed time from the start of EAL 663's turn toward them until it passed to be 40 to 50 seconds. The RR-7 controller testified that the turn was accomplished in two to three sweeps of his radar, and the target proceeded on a southerly course for an additional two sweeps before the targets merged. The time interval between sweep on the radar used by him is ten seconds. The time interval of target observation could be as little as 11 seconds and as much as 29 seconds for two sweeps, 21 to 39 seconds for three sweeps, and 31 to 49 seconds for four sweeps. The average of these three times resulting from the foregoing testimony and computations is 43 seconds from the start of the turn until the time EAL 663 passed abeam PAA 212.

The turn was described by the PAA 212 crew as faster than normal but not abrupt. Based on these observations and the testimony of RR-7 controller we calculated that the turn took 20 seconds, since on the next sweep the target was southbound, and was observed for two additional sweeps. A four-degree per minute average rate of turn would be consistent with this testimony and result in the turn being accomplished in 20 seconds. According the flightpath shown from point of passage was plotted on the basis that EAL 663 had completed the turn to the assigned heading of 170 degrees; that it was on the heading for approximately 23 seconds prior to passing PAA 212 and that it was proceeding at a groundspeed of 206 knots. This groundspeed is based upon the normal performance characteristics of a DC-7B operated generally in consonance will the instructions in EAL's DC-7B Airplane Flight Manual, and under the wind and temperature conditions shown in the data in Attachment #3. The average rate of turn of four degrees per second requires an average 35-degree bank angle, which is within five degrees of the 30-degree bank angle