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Aviation History
1963
1963 - 1337.PDF
FLIGHT International, 1 August 1963 m HOP FOR JETS w/iiiwi COiUMH ICAO Panels as a whole have had an indifferent success: those such as Airworthiness and Jet Operations have given real leadership to the industry, while other Panels, such as those on R/T Speech and Vertical Separation, have yielded little or no return. In the circumstances it is understandable that a number of States attending the last Assembly (Rome, September 1962) agi tated for a termination of the "Panel System"; however, some thing will now be taken out of their argument by the unqualified success of the Panel on Holding Procedures (HOP), which recently produced its first report. I am quite sure that the secret of success of Panels is simply adherence to the concept—as has always been intended but not always applied—that the experts meet without a predetermined "national" position but with a willingness to face the consequences of the argument. In the case of HOP, the argument led to a pro tected airspace for holding, larger than had previously been visua lized, and the meeting accepted it; in the case of the Vertical Separa tion Panel, the argument began to point definitely towards a larger vertical interval; but, as this was highly inconvenient to some States, preconceived notions dominated from the start (e.g., that 1,000ft was a safe interval up to 29,000ft), and the Panel waffled away in a mass of over-optimistic assumptions selected to make the notion look respectable. In the matter of holding, of course we all agree that there ought never to be any need for the manoeuvre, especially in the case of the jet; however, only a few international terminals have their radar so developed that this ideal can regularly be achieved; and, even where they have, occasional reversion to procedural control and the traditional holding patterns becomes necessary—as when London Southern Radar suffered from a power failure last Janu ary and took over an hour to transfer to stand-by. New York, for various reasons, has had similar periods without radar. This being so, some provision has to be made for the jet which, if obliged to hold, will often want to hold high in order to conserve fuel and will therefore require larger than normal protected airspace so as to allow both for its higher true airspeed and for the larger area of uncertainty as to the exact overhead position of the holding facility. The HOP group coped with these problems very well. I do not Propose to go into all their recommendations, since these have only just become available as an ICAO document. However, the entry procedures will be of immediate interest to pilots, especially those who have up till now been trying to apply the FAA recom mended patterns, which demand something of the combined genius of Liebnitz, Gauss and Einstein. The no-wind condition forms the basic case and, for holdings above 14,000ft, might be memorized by:— Turn right from quadrants two and one, A minute on the outbound track; Then right again to hit the cone, And you are settled in the stack. Entry from ^ luourant 1 / 70' /0> E S3 m 90* LH 180* 53 90 m Entry from quadrant 2 From quadrant three and quadrant four The system is the same but turn The shortest arc at the VOR And again for the inbound run. SI 270""^ m f 0 m ' \ \ 90' \/ ID ^^-^ 180* Entry from quadrant 3 270'\^ m " m v , J 90* J-N J ,80- @ Entry from quadrant 4 The strong-wind case does indeed complicate the picture some what, but not enough to outstrip my powers of verse, and I do not see why it need cause any difficulty. When outbound see you don't get blown Across the inbound track and mind You make it a procedural turn The first leg being into wind. 270 There are a few other points to bear in mind in connection with timing, speeds and bank angle but a little practice in a simulator or a Link should soon account for these. Further, since the protected area has been increased only from 24.62 X 27.85 n.m. to 24.87 X 33.9 n.m., I do not see why most authorities could not permit these procedures straight away. The HOP report shows just how to apply the geometry involved, which is something of an advance on so many ICAO recommendations. A little weakness intrudes in the matter of holding airspeeds, where some members of the Panel couldn't understand why there might be a question of buffet in a 25° banked turn at 240kt and 25,000ft or above, but the series "Of Margins and Manoeuvr ability"* had not been published at the time of their meeting and the effect of a turn or a gust on an aircraft taking maximum advan tage of le mensonge aironautique could therefore not be easily assessed. A further imperfection may be seen in a little over-optimism in the matter of VORs with 30° cones of confusion and 4° "To-From" segments; and although it would, I suppose, have introduced a discordant note if someone had suggested working out the size of a pattern based on an area-coverage, pictorial-presentation aid, it is interesting to speculate what the answer might have been if they had done so. My estimate is that, bearing in mind the accur acy and flexibility of this type of aid, the patterns could come down to well under half the size recommended by HOP and the protected area varied as necessary to suit the traffic situation. And, with the inherent simplicity of the cockpit guidance, think how easy the verses would be:— Controller: Epsom race-track five miles long; Pilot: Doo-dah, Doo-dah; Controller: Hold fourteen thou' and you can't go wrong: Pilot: Doo-dah, Doo-dah, Dey! This harmonious state of affairs would, I suggest, relieve much of the tension in the terminal area; and, as tunes are recognized to be more memorable than words, it might give a clue to the R/T Speech Panel. • 'Flight International," 18 April 1963, -Margins and Manctvrability, 5."
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