Page:CAB Accident Report, General Airways DC-3 crash on 1 February 1959.pdf/9

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~ and New Orleans, plus a flash advisory issued by Albuquerque.

_ 9 _

1 We relayed this to the distressed aircraft - he reported that the windshield I of his aircraft was iced over and they could not see out.

Several more calls were made to the aircraft with no response then an answer that 'We're busy now

Air Evac.‘ - Then silence."

The "six feet of ice . . .," emphaSis.

an obnous exaggeration, was probably for

A review of weather conditions shows that temperatures over northern Texas were below freezing at all levels with a pronounced temperature inVersion.

‘ At 1800 on February 1. this inversion at Amarillo was approximately 7,000 'feet.

Below this altitude the mean temperature was about 10 degrees Fahrenheit whereas

between 7,000 and 10,000 feet the mean temperature jumPed to a value of about

25 degrees Fahrenheit. A similar inversion existed at San Antonio at this time. Between 1,000 and 3,000 feet, the temperature at San Antonio was close to‘the freezing point whereas above freeZing temperatures existed in the layer from 3,000 to 10,000 feet.

Under these conditions the most adverse icing conditions would have i followed the slope of the inversion from 5,000 feet near San Antonio rising to the le'u'els imediately above and below 10,000 feet over extreme northern Texas.

The briefing from the Weather Bureau at Pueblo was by field interphone between 1635 and 1650. It consisted of a reading of 1600 hourly weather reports for 13 stations along the route to San Antonio, the terminal forecast for San Antonio, pertinent excerpts from the area forecasts issued by Denver, Fort Worth, The briefing con— cluded with the Winds Aloft Analyses for Pueblo, Amarillo, Abilene, and San Antonio. All of the weather data utilized in this briefing clearly indicated wideSpread low ceilings, restricted visibilities, snow, freezing precipitation and. icing conditions existing along the route. Weather Bureau Forecast Offices at Denver, Albuquerque, Fort Worth, El Paso, and San Antonio had covered the conditions accurately and exhaustively in area forecasts, terminal forecasts, and even in flash advisories which had been issued throughout the day by each forecast office.

At the time of first contact with the ground the aircraft was heading about 75 degrees true; left-wing low by about 10 degrees and descending at approx— imately a 10-degree angle. These figures are readily reconciled with COPilot Wittliff's statement and point to the aircraft being about halfway through a turn from downwind to approach and descending.

As the aircraft slid along the ground, numerous parts, including both engines, were torn free before the aircraft came to rest on a heading of about 1:4 degrees true after sliding 208 feet.

There was about a J40-minute lapse between crash and arrival of fire apparatus.

As a consequence a great deal of the physical endence was destroyed by fire, as were all records being carried. It was not possible, for example, to determine the position of the wing flaps, nor was it possible to determine why the wind- shield de-icers were not effective. Wing de—icers apparently were functioning and testimony of the carrier's maintenance personnel indicates that they should have been in good condition. The landing gear was up.