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    Neil Armstrong 1968 Typed Letter Signed Regarding Updates to the Bell H-13 Helicopter Operator's Manual, Directly from The Armstrong Family Collection™, CAG Certified. Two pages, 8" x 10.5" NASA letterhead, February 23, 1968, to "Commanding General, USAAVCOM" at St. Louis. It reads in full:

    "Dear Sir:

    "This letter is forwarded in lieu of Department of the Army Form 2028, which is not available at this activity.

    "As a result of a NASA aircraft accident involving an OH-13H helicopter, the Accident Investigation Board recommended certain changes to the Operator's Manual, TM 55-1520-204-10. These errors are in the description of unusable fuel, fuel quantity, and caution notes in the present handbook. It was determined by the NASA Accident Investigation Board that the actual fuel quantity of the Bell H-13H can vary from 40 to 46 gallons. The unusable fuel in single pilot high speed flight can be as much as 2 to 3 gallons. Further, in single pilot flight, indications between left and right indicating systems can be much in error due to "wing low" attitude of the helicopter. These items are not covered in the present Operator's Manual.

    "It is our recommendation that the following notes be included in the Manual in the appropriate section:
    a. Unusable fuel can be as much as 2 to 3 gallons, depending on helicopter flight attitude (the greater nose down cruise attitude, the greater amount of unusable fuel).
    b. Single pilot operation results in inaccurate readings between left and right tank quantity gaging due to left "wing low" attitude of the helicopter.
    c. Due to tank manufacturing tolerances, actual fuel quantities can vary from 41 to 23 gallons, depending on aircraft.

    "Present Manual indicates .3 gallons total unusable fuel. NASA tests indicated that in level flight unusable fuel is approximately .5 gallons and in single pilot high speed flight, it is 2-1/4 gallons.

    "We suggest that appropriate revisions be made to the Operator's Manual regarding these discrepancies as soon as feasible. Sincerely yours, [signed] Neil A. Armstrong NASA Astronaut"

    Also included with this lot is a Form 2028 stating "See attached letter". A rare and important internal document bearing a full Armstrong signature in his capacity as a test pilot and astronaut. Very fine. Sealed in numbered archival sleeves, CAG 1000104-018, 1000104-019, & 1000104-020. See adjacent lot for the answer to this request. This lot will include Statements of Provenance signed by Neil Armstrong's sons, Rick and Mark.

    Learn more about Collectibles Authentication Guaranty (CAG).

    Auction Info

    Auction Dates
    May, 2019
    9th-11th Thursday-Saturday
    Bids + Registered Phone Bidders: 6
    Lot Tracking Activity: N/A
    Page Views: 445

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