Page:CAB Accident Report, Western Air Lines Flight 221.pdf/10

 Note Until the flight crews become accustomed to the changes in procedure in items #4 and #5 the captain should brief his crew prior to takeoff (a) second officer on command will set power, (b) first officer on command will retract and extend gear."

The captain did not. brief the crew for Flight 200/221 regarding these changes in procedures.

Analysis

It was determined that Flight 200/221 was properly dispatched in accordance with company procedures. The crew had been well briefed regarding the weather conditions that were expected at Los Angeles

Observations taken by both tower and UWSB personnel were in accordance with current procedures. It was on the basis of these observations that the airport remained above published minimums throughout the approach. However, it is considered that the prevailing visibility of 1/2 mile, which was reported to the flight, and the RVR value of 5,000 feet were not truly representative of the actual visibility conditions experienced by Flight 221 along runway 25L. Although the RVR (for runway 25L) remained above 5,000 feet throughout the approach of the flight, it must be noted that this value was only representative of the transmissivity of the atmosphere over the 750-fool baseline of the instrumentation which is at the approach end of that runway. It was not representative of the fog-induced non-homogeneous conditions which existed beyond the approach end of the runway. Similarly, the area of thick patchy fog was beyond the visual range (1/2 male) of the observer in the tower and was therefore, not detectable from his location. The pilot's actual "visual range" probably varied from the 5,000 feet reported, to close to zero in patches of fog.

During the approach to runway 25L the crew sighted the runway lights when the aircraft was in the vicinity of the middle marker. The dense fog condition which existed beyond the pilot's forward visibility range would not have been discernible at this point, nor would it have been discernible to the crew subsequently during the flare and landing transition. The weather information received by the flight from approach control as well as the captain's observations of adequate runway visibility indicated that the weather conditions were within the regulatory parameters which permitted landing and warranted continuation of the approach to touchdown.

It is to be noted, in light of these conditions, that the crew's visual acuity would have been enhanced had the landing lights been extinguished at touch down thereby eliminating the resultant glare.

It was indicated by the crew that touchdown was effected approximately 1,000 feet beyond the runway threshold However, computations based on applicable performance data give an average acceleration of 2.2 knots/second and elapsed time of 11.8 seconds, from lift-off (100 knots) to initial impact (126 knots), and result in a lift-off point approximately 3,250 feet beyond the runway threshold Thus, based on this lift-off point and on crew testimony regarding elapsed time between touchdown and the initiation of go-around procedures it is indicated