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#131
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"B2431" wrote...
On C-130s we had the SPR (single point refuling panel) where they hooked up the nozzel. It had indicators reading pounds for each of the integral tanks. That's a common arrangement. Tactical aircraft with SPR may not have any indicator at the panel; simple lights indicating a full/not full tank (closing a float switch) may be used instead. If a partial fuel load is desired, it must be selected by fully fueling specific tanks and/or monitoring the cockpit fuel gauges. In the case where over-the-wing fueling is used (in the past, commonly done with the wing drop tanks on the A-4), either the tanks are filled completely or a specific quantity in gallons specified. Even though the A-4 fuel system indicated in pounds, the 300-gallon (2000 lb nominal) drop tanks were filled with 150 gallons for a "half drop tanks" load, regardless of fuel type or density. Minor weight discrepancies due to fuel type (JP-4 vs JP-5) or temperature were disregarded, since fuel planning assumed the worst case (low density or weight) and performance effects due to slightly higher gross weight with high-density fuel were negligible. For the SPR systems with indicators on the panels, the person doing the refueling needs to know little more regarding the specific fuel upload than the final total fuel load (or sometimes the load in each tank). By manual or automatic tank selection and shutoff valves, the tanks are fueled until the final load is achieved. The fueler does not need to monitor or convert volume (gallons or liters) to weight or mass (pounds or kilograms) -- he simply uses the indicators in the aircraft fuel system to directly read the fuel on board in the airplane's native units. Sometimes, e.g. when several trucks may be required to refuel a large airplane, an estimate of required fuel may be given to the fuel company dispatcher so [s]he can dispatch the appropriate number of trucks. In commercial aviation this figure is seldom, if ever, used as an "order" for a specific quantity; it is only a planning guideline. For example, when arriving at a station in a 747, I will notify the ops center of the estimated fuel remaining (in Kg) on shutdown. They will then estimate the fuel load required for the next leg and notify the fuel dispatcher. When the refueler comes to the airplane, he never knows the number of gallons/liters required. The airline ramp ops people will tell him the preliminary or final fuel load in Kg, and the fueler will set that figure on the airplane refueling panel (the 747-400 is almost completely automatic; once a total fuel load is set, the airplane system automatically controls the feed to individual tanks). The fueler has no idea how many gallons, liters, or Kg the airplane will require -- only the final load. He records the gallons or liters delivered, after the fact, on the receipt for billing. The bottom line is that conversion of units is seldom a critical problem in refueling modern commercial airplanes. |
#132
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"Pat Norton" wrote in message ... Tarver Engineering wrote: Why change from the units of aerospace to some other arbitrary set of units in the first palce? That question does not parse. The problem is not a 'change' from setA to setB. The problem is multiple units for the same thing. UnitX coexists with unitY (and perhaps unitZ). You may wish to ask: Not at all, in the Western World aerospace has been feet, pounds and clockwise. I will agree that your alternative units have merit, but not in aerospace. |
#133
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"John R Weiss" wrote in message ... "Tarver Engineering" wrote... And you start with pounds as the basis and convert to have the fuel vended, no matter what units of volume are used. Then the weight of the airplane is checked to see if the fuel got onboard. So, the FE begins with a takeoff weight, calculates the fuel to be ordered and leaves the weight on the dash for the pilot to cross check. Nope! It is apparent you don't know at all what you are talking about. In "a high reliability sysetm" such as that in a 777 or 747-400, the fuel vendor is simply told the "final fuel" figure in kilograms My goodness Weiss, you mean what I wrote in the first place is completely correct. No, your fantasy "explanation" of what you think might happen isn't anywhere near "completely correct." No. |
#134
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"Alan Minyard" wrote in message ... snip You are right, when do you intend to start the conversion to the inch?? One tenth of a foot is already an American engineering standard for transportation. |
#135
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I was visiting relatives in Sweden with my uncle. They had a nice 10 acre farm.
My uncle is from Texas and said he had a farm and could get in his car, drive all day and still not be to the other side. The Swedish relative said: "Ya, I had a car like dat vunce too." -- Charlie Springer |
#136
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#137
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Hey you guys. The French System (Now called Metric though any system of
measurements is a metric) was officially adopted by the US Congress in the 1800's. I think that over a hundred years of refusal by the people would convince anybody in business to pull a product. Why do you suppose non-profits and governments still push metric? -- Charlie Springer |
#138
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Michael Williamson wrote:
US military airports now give Terminal Area Forecast visibility in metres. All without a fuss. In some cases they might, but the last time I got ATIS here at Davis Monthan AFB, visibility was in nautical miles You may be thinking of the METAR rather than TAF. In any case, METARS use statute miles not nautical miles. I have just been given the following TAF for Davis Monthan AFB (visibility in meters): KDMA 280505 14006KT 9999 BKN290 QNH2990INS WND VRB06KT AFT 17 T29/23Z T13/13Z Can you check again? |
#139
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Gord Beaman wrote:
"The court heard he had miscalculated the conversion from US gallons to litres Very interesting Pat, thanks. Here are two mo ************************************** The aircraft landed firmly in a steep nose up attitude which caused the tail area to make contact with the runway surface. [...] The Loadchit and Load message form was given to the Commander at Menorca. It was annotated "All weights kilos" ... Total passenger weight 18,251 kg Baggage 3,692 kg On the Loadsheet the Commander had converted the baggage figure into pounds but had entered the passenger weight as '18251', the weight in kilograms recorded on the Loadchit. Using the conversion multiple 2.2046, this figure should have been '40236' ************************************** http://www.dft.gov.uk/stellent/group...ty_500650.hcsp ************************************** The accident occurred when both engines lost power during a ferry flight from Tangiers to Guernsey. The commander ditched the aircraft into the sea near the island of Jersey but he did not survive. [...] The aircraft was not carrying sufficient fuel for the intended flight. The commander apparently ignored pre-flight and in-flight indications that he should land and refuel in France. It is difficult to understand why the commander thought the aircraft could fly for 8 hours unless he miscalculated the endurance. In aviation, the variety of units used (eg fuel quantities can be given in litres, Imperial gallons, US gallons, pounds or kilograms) are a potential trap for the unwary when the need to convert from one to another is overlooked or miscalculated. ************************************** http://www.dft.gov.uk/stellent/group...ty_502535.hcsp |
#140
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