Page:CAB Accident Report, American Airlines Flight 6001.pdf/8

 Special

0404

Closed, indefinite ceiling 400 variable, overcast, 1-3/4 miles, light fog, 1020.3, 51, 49, NNW 3, 30.12, ceiling variable 400 to 600.

Special

0413

Instrument, measured 700, overcast, 2 miles, light fog, 1020.3, 51, 49, NNW 3, 30.12.

In addition to the hourly observations taken by the Leather Bureau and included in the hour]y teletype sequences other observations are made for keeping the weather up to date. These include "Special", "Local Extra" and "Check" observations. The "Special" observations are required to be transmitted by teletype and radio although teletype congestion may delay their transmission. These "Specials" are filed whenever changes of considerable importance occur. The "Check" and Local Extra" observations do not necessarily contain any changes from the previous observations and if they do the changes are of small magnitude. These are not handled by teletype because of the lack of available communication time. When the ceiling or visibility approaches the operating limits of an airline even the small changes contained in the "Local Extra" or "Check" observations may be important to a particular airline. It had been agreed at Burbank between the airline operators and the Weather Bureau that whenever it was important for an airline to be kept advised of all weather changes they would notify the Leather Bureau which would then see that the airline received promptly all changes contained in any type of observation being made. In the particular case of this flight the first observation indicating the lowering of ceiling below the operating minimum was the "Record" observation at 0323 in which a remark was inserted that the ceiling was variable 600 to 700 feet. Following this, at 0345, a "Local Extra" observation showed a measured coiling of 600 feet which was below Burbank Airport's operating minimum. American Airlines had not requested that they be kept advised of all weather changes and, therefore, had not received the report showing that the weather had dropped to below instrument approach minimums. Company personnel indicated by their testimony that they had made a visual observation of their own and assumed that no weather change had taken place.

DISCUSSION AND FINDINGS

The facts disclosed by thus investigation center first around the pilot's action when he found it impossible to maintain visual reference to the ground and second around the failure of company ground personnel to obtain pertinent U. S. Leather Bureau reports and the inadequacy of the weather information winch they furnished to the pilot.

Considerable significance must be attached to the manner in which this flight was handled by ground personnel. Considering the forecasts of both the U. S. Weather Bureau and the company, as well as the actual reports available to the pilot and to the dispatcher, it was evident that conditions at Burbank were varying between below minimums and a marginal condition barely within minimums. While the last report the pilot had at the tine of his approach to the field indicated that weather was within company minimums there were three subsequent observations, at least two of which could have been made available to him, that indicated the ceiling would be below minimums at the Burbank Airport at or about the tine the flight was expected to arrive over the field. Whereas the pilot did establish visual contact with