Page:CAB Accident Report, United Air Lines Flight 823.pdf/31

COPY

Mr. B. R. Allen Director, Bureau of Safety Civil Aeronautics Board Washington, D. C. 20428

Dear Mr. Allen:

This is in reply to your letter of November 17, 1964, regarding discrepancies in the Pyrene fire extinguisher system on the United Air Lines Vickers Viscount aircraft.

Our studies concerning the Viscount CO2 system of which you were advised in our letter of October 19, 1962, have not been completed. For your information, Vickers Armstrong has notified all Viscount operators with cockpit CO2 systems to manually discharge the extinguishing agent into the lower cargo bin

Pending completion of our investigation, as an interim precautionary measure, we are instructing our field personnel to request all Viscount operators with this same system to take the following action:


 * 1) Re-emphasize to their pilots the need to don smoke masks before discharging the lower cargo bin CO2 cylinder.


 * 1) Instruct their pilots to manually discharge CO2 for the lower cargo compartment


 * 1) Notify their pilots that it is possible for CO2 to leak into the cockpit area.

We certainly appreciate your recommendations.