Page:CAB Accident Report, Pennsylvania Central Airlines Flight 19.pdf/87



The possible effects of lightning upon aircraft should be the subject of continued research. The difficulties of direct research upon a natural phenomenon occurring unpredictably as to time and location, and only at considerable intervals in any particular area, are obvious. Nevertheless, much has been accomplished in the last twenty years in a number of laboratories. The National Advisory Committee for Aeronautics has for some time had a special subcommittee on Lightning Hazards to Aircraft, on which interested Government departments and airlines and industrial laboratories having given special attention to lightning are represented, and some specialized researches have already been conducted. We recommend that further attention be given to such research, and that there be included among other matters the study of the optical quality of lightning flashes, the nature of their blinding effect, and the extent to which protection can be given against blinding by the use of windshield materials of various light-transmission characteristics; the possibility of acoustic shock through radio earphones, and the extent to which the liability of such shock would vary with the particular characteristics of the earphones used and of other parts of the radio installation; and the possible mechanical effects of lightning on aircraft in flights.

A continuation and accentuation of research on atmospheric turbulence. Here again, as in the case of lightning, direct research is difficult, but a substantial amount has already been accomplished. We believe it important that the existing store of knowledge of the nature of atmospheric turbulence, of its structure when its severity is at a maximum, and of its effect on the flight performance and the control of the aircraft should be extended as 