BLIND FLYING

Evening Post, Volume CXX, Issue 129, 27 November 1935, Page 10

BLIND FLYING

AERO CLUB ADVANCE

RELIANCE ON INSTRUMENTS

TUITION TO BE GIVEX

In deciding to give facilities to its members to train in blind flying, the Wellington Aero Club is taking a lead in aero club instruction in New Zealand, for hitherto blind flying instruction could be had only at the Air Force stations at Wigram and Hobsonville, j and has been practically beyond amateur pilots. The absence of facilities has handiI capped New Zealand club pilots very 1 greatly, and if one goes over the list of flying tragedies in this country one [will and that the great majority followed on flying in cloud or fog without suitable instruments and because of lack of knowledge of blind flying technique. None but a superman can fly blind for any .time without special instruments,' for, in the blank of fog or storm of rain, the pilot cannot, with only standard instruments before him, know whether he is flying level and on a straight course, or is flying on a fatal curve as so many have done. Particularly in New Zealand, where high hills are seldom far from air travel lines, is blind flying essential to safe flying. A knowledge and practical experience of blind flying is, of course, insisted upon for pilots who will operate the commercial air services to be commenced within the next few weeks. Light machines are not as a rule fitted with special instruments, but commercial machines today carry them as standard equipment. No doubt they will become standard equipment on all machines in the future, in spite of their rather high cost and of the fact that their practical use is not at all a simple matter. Theory is all very well, but blind flying efficiency is gained only after hours of practice. | THE GYRO PRINCIPLE. There are several types of blind flying instruments, but all depend upon the gyroscope in one form or another. The Wellington Aero Club has decided to install the Reid and Sigrist turn and bank indicators, which are largely used in instrument flying training in England. A spinning gyroscope resists attempts to move it from the particular plane in which it lies. In the case of instruments which indicate the swing (as from level flight) the gyro axis remains in its original position, and the displacement angles are shown on the instrument board dial. In the case of turn indicators, where a rate of turn must be given, the indication is obtained from the fact that the gyro, with its axis lying across the direction of travel, tends to process away from the direction of the turn, with more or less force, depending on the rate of turn. Automatic pilots, installed in many commercial aircraft, merely carry the action further by transmitting the forces to the controls, so correcting the various deviations. Just why the standard compass fitted on all aircraft, light and commercial, fails to keep the pilot on a true course in blank-out weather would require a technical explanation, but in blind weather, when the natural horizon is utterly blotted out and the spirit level may be indicating level flight or a bank (if the bank is correct for the type and speed of machine the bubble will be dead centred, as in level flight, and centrifugal forces confuse gravity, the compass may go crazy and move madly while the aeroplane, as far as sensory impressions tell the pilot, is flying truly on a straight and level course. The great problem before the training pilot, so those who know the way through blind weather have said over and over again, is to learn to put aside all his own impressions, no matter how positive he may be that he is right, and to depend with absolute faith in the instrument board before him". And that must take a lot of doing. MISERY UNDER THE HOOD. In practice the blind flying student is not taken up in the filthiest weather of the year, but is hooded over with only the illuminated instruments in front of him. The instructor sits elsewhere and sees that things go right. It does not sound a particularly happy way of spending a bright sunshiny afternoon, but those pilots who look to advancement in serious work have no option but to go through with it. "Few sensations are more physically disturbing than one"s first spin under the hood," wrote an English writer in "Flight" recently. "Although a pilot may be accustomed to the sensation of spinning and be undisturbed by them, even when cut off from the outside world, the human balancing organs cause great mental and physical havoc ■at the moment of recovery. AVhen the j machine has actually stopped spinning and is in a vertical or near-vertical dive one has the strongest possible sensation of continued spinning, though in the opposite direction. Hence the absolute necessity for plenty of practice and for an unmistakable technique of recovery. ... So quick and complete is a normal recovery . . . that there is danger of a second stall. The pilot opens the hood and breaths a little slipstream before continuing his selfimposed torture. He becomes used to it in time."

All the pilots engaged for the commercial services to be operated by Union Airways and Cook Strait Airways have gone through their courses in "blind flying, and Squadron-Leader G. L. Stedman, pilot instructor to the Wellington Aero Club, will go down to Christchurch shortly to enjoy his thirty or forty hours of happiness beneath the hood.