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Aviation History
1963
1963 - 0048.PDF
44 FLIGHT International, 10 January 1961 Al R COM M ERCE FLASH IN THE PAN WITH this issue of "Flight International" we begin a new series of commentaries on the subject of flight operations, with safety as the underlying theme. The initials C.C.J, are those of Capt C. C. Jackson, executive secretary of IFALPA, the International Fed eration of Air Line Pilots Associations. Capt Jackson served with RAF Bomber and Transport Commands from 1936-1945, and was with BOAC from 1946-52, first as a line captain and subsequently as assistant flight operations officer and flight simulator instructor. He has played a leading part in the development of IFALPA to the respected status it enjoys today as the voice of pilot opinion in the field of flight safety and efficiency. He has marshalled pilot thought over a period of ten years so that now a substantial body of piloting knowledge on technical subjects has been written down and the world pilot group organized in such a way that collective opinion can be given on almost any operational subject to ICAO or the industry. These new commentaries—initially planned to appear at approxi mately monthly intervals—are an extension of the above process of writing down pilot thought. They will, however, aim princi pally at the "forward areas" of the industry, areas where equip ment specifications are not yet settled and where, perhaps, pilot opinion is also undecided. In this the feature will usually follow the line already dominant in IFALPA; but it is, nevertheless, in tended to be independent in the true sense and may therefore occasionally echo a minority view. It will be directed towards a wide readership, including sections of the industry who may not have a piloting background. At the risk of occasionally boring the experienced pilot the intention is to keep the material readable to the layman. IN the United States a little while ago a pilot was taking off in Itt oppose slnse to the approach lights in weather o 200f. and half a mile; the strobe flashers were on and, looking at then, "rough one propeller, he thought that the prop was stationary he Tothought that he was in a 30° bank. On reference to the j instruments, however, he found that the engme revs were norma; | and he had no bank. _ This and one or two other incidents have caused me to revise m> opinions about flashers in the very-low-visibility ranges. Of course Mr Ted Calvert has always been cool towards them, and would probably oppose them outright for any minima below 200/i. 1 know a number of pilots who would agree with him. However, the majority of American domestic pilots have been consistent^ enthusiastic about strobe centreline approach lights and, before taking up any rigid position, it would seem as well to look into the advantages of the lights as well as into the disadvantages. After all these lights are now installed at Orly, Hamburg, Copenhagen and Cologne and seem likely to spread over Europe in the very near future. Pilots, operators and airport authorities need to know: are they going to do good or harm? On the credit side I think there is little doubt that the high-inten- tensity incandescent strobe penetrates the fog better than does the lower-powered standard approach light. Reports indicate periods of between 3sec and lOsec in which the flashers are picked up ahead of the fixed approach-lights. This is comforting to the pilot ap proaching through the murk; it confirms that the runway is definitely somewhere ahead and, if he is lined up with the direction of the flash sequence, he can just keep going on down. This in fact also applies to the non-aligned case provided that cloudbase is above about 200ft or the runway visual range above 1,000yd. With this kind of limit there is enough ground-plane information for the pilot to judge his attitude from external references and, with the present-day approach speeds of propeller-driven aircraft (we will leave the 200/4 debate on the jets for another day), there is just enough time to make a minor jog into the centreline. With regard to the position below 200/J very little data exist. Indeed, the main weakness of the enthusiastic reports on flashers is that when they are closely examined, they nearly all relate to weather minima very much above 200/i. However, one or two reliable cases exist ia the low-minima brackets; the best of these is the series of tests carried out some five years ago in the United States by Ace Robson (in a Convair 240) and Bob Gates (in a DC-3). Both pilots commented very favourably on the flashers. I haven't the reports in front of me now, but I believe that the great virtue found with the flashers was the fact that they showed through the fog some five seconds before the fixed approach-lights. On the other hand, my recollection of the films taken during these approaches is that all of them showed in good alignment with the runway in the first place and that there was no example of a "jog in" during the five seconds in which the strobes were visible and the fixed lights were not. Now that, to my mind, is the critical phase in these low visibility approaches and it is here that we pick up the debit side of a line of flashers. By way of illustration, here is an extract from the report of the Cessna crash at Luxembourg on January 9,1962:— "G-ARNUflew over the first Calvert bar at 1726 and arrived to the right of the centreline in line with the runway threshold. "At 1736, i.e., 10 minutes later, the pilot of an Aero Commander, who was attempting an ILS landing, also arrived at the Calvert lights to the right of the centreline. He attributed this displacement to a question of pilotage. He came down to 200ft and saw the moving glow of the EFAS (Electronic Flash Approach System) but was unable to distinguish the Calvert cross-bars, which were merely a weak halo. He carried out the normal missed approach procedure and was able to land ten minutes later, the meteorological conditions having slightly improved. The evidence gives reason to assume that the pilot ofG-ARNU, also arriving in a similar position, saw the moving glow of the EFAS. He probably abandoned his instrument flight in order to look out to the left, then to turn to the left, so as to locate the lights visually." Here we seem to have clear evidence that the Cessna pilot picked up the line of flashers well ahead of the fixed lights but that he was not in the groove for a landing and so was making a course correc tion or overshoot on the visual cues from the single line of lights Now this cannot be done. Mr Calvert explaiaed it all about 15
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