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Aviation History
1957
1957 - 0140.PDF
•-m (Lett) Four - ringed conference at Nairobi (Capt. W. R. Hutche- son on the right). Note the new type of round - tipped D.H. solid alloy - bladed propeller, now being experimentally fitted to Britannias. Touch- ing it on the right is Mr. Ross Hall of de Havilland Propellers. BRITANNIA DRESS REHEARSAL . . . the pleasing proportions of the new terminal building, the modernsurveillance radar mounted high on its slender concrete pillar, the businesslike fuss going on around a CA.A, Viscount and a shinywell kept DC-3 of Hunting Clan's Africargo division. Dispersed over on the south side of the airport are Vampire Trainers andDakotas of the Southern Rhodesian Air Force, sparkling silver and red in the sunshine.Leaving us for 24 hours in the good hands of Paddy Anerne, B.O.A.C.'s Salisbury representative, our Britannia flies on toJohannesburg, terminus of the B.O.A.C. Springbok service. The 5,600-mile journey back to England, via the same sectors, issmooth, unflustered, comfortable. I had flown 40 hours in the Britannia, and in that time had developed an affection for theaeroplane which will, I venture, be shared by all who fly in her. BRITANNIA 102 FLIGHT-PLANNING PROCEDURE All transport aircraft today are operated to a rigid cruise-procedure, and none more so than those powered by turbines. The procedure evolved by B.O.A.C. for the Britannia owes muchto their Comet I experience; in the course of adaptation it has become rather more complex, but no doubt it will become simpli-fied and streamlined with experience. Certainly few of B.O.A.C.'s Britannia passengers would fail to be impressed by the care withwhich every sector of their flight was planned, whether or not they understood the technicalitiesThere are two basic Britannia 102 cruise techniques: (1) "fast and level" and (2) "high-stepped," the first being a constant-height cruise at about 20,000ft, and the second a cruise which begins at this height and finishes—after 2,000ft stepped climbsevery two hours—at about 30,000ft. The choice between these two techniques depends upon sector length—and to a lesserextent upon payload and winds. For sheer economy, of course, a climb cruise, vide the Comet 1, would be best: but this is The Britannia as seen from Salisbury's fine new control tower. vitiated today by air traffic control quadrantal-separation con- siderations In any case it is not, with the Britannia, sufficiency more economical than the "high-stepped" cruise to justify the extra attention it requires in flight. . . . Basis of the flight planning procedure for the Britannia is tfieOperations Manual, a document of tables and graphs devised by the B O.A.C. Britannia Fleet and Operations Development Unit.From these the flight crew extract the fuel requirements by feeding in the five variables of payload to be lifted, sector length,winds, temperature, and altitude. This is what has to be done between each sector.(1) Knowing sector length, read off from the Ops. Manual "minimum sector fuel." This, simplified, comprises (a) normalflight fuel for take-off, climb, cruise, descent and landing; (b) normal reserves: six per cent of cruise fuel; fuel for diversion, andfor holding and landing at the alternate airport; and 450 kg emergency reserve; (c) 315 kg of unusable fuel (this is likely tobe reduced by changes to the tanks) and 225 kg for taxymg. "Minimum sector fuel" can be exceeded, according to the flightplan, but never reduced. (2) Check payload with traffic department.(3) Ascertain zero fuel weight (which varies with basic opera- tional weight) from this payload. (4) Check the forecast winds with met.(5) If winds exceed those allowed for in the minimum sector fuel—which they will do on 85 per cent of occasions—calculatefuel needed. Thus find approximate take-off weight. (6) With this approximate weight enter special tables in theOps. Manual and read off—very easily—the approximate height to fly, as near as possible, to Vn,, (i.e., normal operating speed, or235 kt for the Britannia 102) without exceeding it. (The never- exceed speed V», is 276 kt.) This ensures that cruising speed is asnear to V llo as possible without going too low and having tothrottle—which is uneconomic. (7) Having now got approximate weight and height to fly, andknowing en route temperature deviation, enter further Ops. Manual tables to find the T.A.S. and fuel-flows. Then calculate exact totalflight fuel, and hence exact take-off weight. All the information necessary for a normal flight plan to be prepared has now beenobtained. The above procedure is for a typical "high-speed level" cruise.Other tables are provided in the Operations Manual for the economical long-distance "high-stepped" cruise; for a throttledcruise, should this be necessary; and for both three-engined and two-engined cruising. There is a table also showing fuel flows inthe holding condition. A "Howgozit" chart (of the kind pioneered by the Comet Fleet)is used in flight to keep a check of fuel remaining against distance-to-go. TIMETABLE FOR THE BRITANNIA'S INAUGURAL "SPRINGBOK" SERVICE To Johannesburg Dep. London Arr. Rome Drp. Rome Arr. KhartoumDep. Khartoum Arr. Nairobi Dep. Nairobi ... Arr. Salisbury ... Dep. Salisbury ... Arr. Johannesburg* ... BA115 Tuesdays GMT Local 1200 1200 1570 1620 1605 J705 2310 01102355 O1SS 0405 0705 0450 0750 0855 f055 0940 1140 1150 1350 BA121 Fridays GMT Local 1200 1200 1520 1620 1*05 1705 2310 01102355 0155 0405 0705 0450 0750 —. — — — 1050 1250 BA115 Saturdays GMT Local 1200 1200 1520 1620 1605 1705 2310 01102355 0155 0405 0705 0450 0750 0855 1055 0940 1140 1150 1350 From Johannesburg Dep. Johannesburg Arr. Salisbury ... Dep. Salisbury ... Arr. NairobiDep. Nairobi ... Arr. Khartoum Dep. Khartoum Arr. Rome Dep. Rome Arr. London* ... BA116 Mondays GMT Local 0915 1115 1130 1330 1215 1415 1630 1930 1715 201S 1125 2315 2210 0010 0545 0645 0630 0730 1010 1010 BAt16 Thursdays GMT Ucol 0915 1115 1130 1330 1215 1415 1630 1930 1715 201S 2125 2325 2210 0010 0545 0645 0630 0730 1010 fOJO BA122 Sundays GMT Local 0915 1115 _^_ 1515 1815 1600 1900 2010 2210 2055 2255 0430 0530 0515 0615 0855 0855 •Arrival at Johannesburg and London on the following day.
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