A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: A-10 Sextant Manual
From: Gary LaPook
Date: 2009 Jun 19, 21:30 -0700
From: Gary LaPook
Date: 2009 Jun 19, 21:30 -0700
I left out a discussion of the minimum fuel reserve for this flight. I have always been under the belief that the only time you have too much fuel on board is when the plane is on fire. Since this flight would be conducted as a general aviation flight, governed by the provisions of Federal Aviation Regulation Part 91, the only requirement is that you have a 45 minute reserve of fuel when you take off. I don't know about you, but a 45 minute reserve for a 21 hour flight seems a little thin, only 3.5%. But due to practical considerations, I think it makes sense to consult the regulations for airline operations which are governed under FAR Part 121. FAR 121.641 states that for a piston powered airliner on an international flight, a "Flag" operation, that it carry 15% more fuel than required to get to the destination and then to the alternate, plus an additional 30 minutes. But this is limited to a maximum requirement of 90 minutes so any flight over 6:20 hits this limit. Another provision of this regulations states that a flight going to an island where no alternate is available must carry an extra three hours of reserve fuel. All of these reserves are after allowing for predicted winds. So using these more reasonable requirements, a 15% reserve on a 21 hour flight is 3:15 which is close to the three hour requirement without an available alternate. So, I think that the 15% requirement or three hours, whichever is GREATER, constitutes a reasonable reserve for an overwater flight. See: http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&sid=8682854bee9ec7c8ef0bbc625461a7d4&rgn=div8&view=text&node=14:184.108.40.206.220.127.116.11&idno=14 gl http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&sid=8682854bee9ec7c8ef0bbc625461a7d4&rgn=div8&view=text&node=14:18.104.22.168.22.214.171.124&idno=14 Gary LaPook wrote: > You can fly there in a Cessna 172. The closest airport is Monterey from > which it is 2012 NM to Hilo on the Big Island. It isn't much farther > from several other California airports, 2041 from San Luis Obispo; 2064 > from Santa Barbara; 2091 from Oxnard and 2096 from Camarillo. I've > heard that from the mainland to Hawaii is the longest non stop leg you > must fly anywhere on earth but I haven't checked this out myself. After > Hawaii you can hop scotch across the Pacific with all the rest of the > legs less than 1500NM. > > A Cessna 172 has a maximum gross weight of 2300 pounds, and an empty > weight of about 1400 pounds leaving a useful load of about 900 pounds. > If the pilot weighs 200 pounds he can then carry 700 pounds of fuel. > Look at the cruise performance table I posted before at: > > http://firstname.lastname@example.org/8.jpg > > This shows that at 10,000 feet you can cruise at 96 knots on 45% power > on a fuel flow of 5.4 gallons per hour which is the same as 32.4 pounds > per hour. This means that you are getting a specific range of 2.96 > NAM/lb (Nautical Air Miles per pound.) 2012 NM divided by 2.96 NAM/lb > gives a required enroute fuel of 679 lbs which means you could make the > flight with a 21 pound fuel reserve and still stay within gross weight > limitations. This would allow you to fly an additional 62 NM. The ETE is > about 21 hours. > > > But, that might be cutting it a little too close.........!! > > and it doesn't allow for taxi and climb fuel or for any headwind > component. Plus the ferry tank would weight about 50 pounds. (You will > need a form 337 for the ferry tank installation.) But still no problem > because it is easy to get a ferry permit from the FAA authorizing you to > fly 10% over gross giving an additional 230 pounds of useful load. Take > away the fifty pounds for the ferry tank and you still get to carry an > additional 180 pounds of fuel giving you a total of 880 pounds of fuel, > 201 pounds of fuel more than the enroute fuel, enough to allow a reserve > of over six hours or for a total drift from a headwind of almost 600 NM. > Since the maximum endurance will be 27 hours, this is enough to > compensate for a 21 knot headwind component (but this would leave no > reserve.) > > So get the tank installed, get a ferry permit and wait for a day when > the winds are forecast to have less than a 10 knot headwind component > and go for it! This will still give you a reserve of 340 NAM and about > 3.6 hours. With a half dozen, hundred dollar hand held GPSs sitting on > top of the instrument panel the navigation is trivial and you will know > your ground speed and position at all times. Compute an ETP and a PNR > and make your decision to continue or to turn around _before_ the point > of no return based on your ground speed and updated wind information > from the weather briefer, oh you will need to rent an HF radio too. You > will also need to make position reports to the FAA every five degrees of > longitude through ARINC on the HF. > > Actually one of the biggest problems is not fuel but oil consumption. > The FARs limit the fuel capacity, and so the endurance of a plane, based > on the allowable oil consumption of the engine type. Since the standard > tanks in a C-172 don't allow an endurance of 27 hours, it is possible > the engine could use up all the oil in the crankcase long before you run > out of fuel. For a flight this long you might need to come up with a > provision to add oil in flight and this is sometimes done with a hand > held pump and a tube going through a hole in the oil filler cap. > > Many, many small airplanes have made this trip and on to Australia so it > is not an unreasonable risk to take. It will cost a whole lot more than > an airline ticket. 100LL fuel is $4.60 at Monterery so the fuel alone, > (21 hours at 5.4 g/h) is $521 to get to Hilo. Gas at Hilo is $5.46 so > $619 for the return fuel. Add to this your engine reserves and it gets > expensive fast. If you could find someone to rent you a plane and allow > you to tank it and take it to Hawaii, the going rate is about $110 per > hour times 21 hours equals $2310 for one person on this one way trip, > $4620 round trip! Hope you have won the lottery! > > > So, send me a postcard from Honolulu. > > gl > > > > > Greg Rudzinski wrote: > >> Gary, >> >> A thrilling first hand story! Glad you survived to tell us ;-) There >> was an episode of Magnum P.I. (TV) from the 1980s that featured one of >> the characters flying a Cessna from Los Angeles to Honolulu. Is this >> possible? Hollywood usually gets things wrong. If you were to fly from >> California to Hawaii in a small airplane what plane could do it and >> would it be an unreasonable risk? >> >> Greg >> >> On Jun 14, 1:56 pm, "glap...@pacbell.net"
wrote: >> >> >>> Mike Burkes ask me to give him more information concerning the engine >>> quitting while I was flying across the Atlantic in a Cessna 172. Since >>> I have already typed it up for him I figure I will bore you guys with >>> the story too. >>> >>> "I was ferrying a new C-172H to the Cessna distributor in Brussels in >>> 1978. That was the model that Cessna switched from using a Continental >>> engine to a Lycoming in the C-172. As in the past, the ferry company >>> equipped the plane with a fifty gallon ferry tank placed on the floor >>> where the co-pilots seat had been, that seat had been folded up and >>> placed in the baggage compartment. The ferry tank was plumbed into a >>> "T-fitting" in the fuel system downstream from the main fuel selector >>> valve and had its own on-off valve. >>> >>> Departed at midnight, IFR out of Newfoundland for the Azores as there >>> was ice in the clouds all the way to Iceland on the northern route. >>> Climbed to FL 100 on the main tanks then turned the main fuel valve >>> off and the ferry valve on. >>> >>> The first land you come to on that route is the island of Flores which >>> is at the northwest end of the Azores chain, 1050 NM from >>> Newfoundland. You can't land there but must continue to the airport on >>> Santa Maria island at the far southeast end of the chain, about 400 NM >>> further. I had flight planned 14 hours enroute with 16 hours of fuel >>> onboard. >>> >>> Shot some fixes during the first few hours to check ground speed and >>> drift. About four or five hours into the flight (I don't have my notes >>> with me) the engine stopped cold. That gets your attention. I lowered >>> the nose to maintain flying speed and then the engine started running >>> again. So I leveled off and the engine quit again. I went through >>> several of these cycles and determined that the engine would run with >>> the nose down but not in level flight so I kept the nose down, DUH! I >>> thought this through and theorized that after the fuel had burned down >>> to a certain point in the ferry tank, sitting next to me on the floor, >>> that it did not supply enough fuel pressure to push the gas through >>> the carburetor in the Lycoming engine although there had never been a >>> problem with this ferry tank arrangement in earlier C-172s. So by >>> lowering the nose I was raising the ferry tank higher above the >>> carburetor supplying a greater head of fuel pressure and this got the >>> engine going again. >>> The only problem with keeping the nose down was that I was descending >>> towards the Atlantic. When I got down to 2,000 feet (actually FL 020 >>> since the altimeter was set to 29.92, the standard practice over the >>> ocean), as low as I dared to go without a local altimeter setting, IFR >>> at night in the middle of the Atlantic, I turned the ferry tank off >>> and the main tanks back on and climbed back up to FL 100. I repeated >>> this cycle three of four times (maybe it was five or six times, I >>> don't remember right now), each time the engine would quit again and I >>> would have to keep getting the nose lower and lower to get the engine >>> to run again. I had to do this to get all of the fuel out of the ferry >>> tank so I could make it to Santa Maria. Finally the engine wouldn't >>> keep running no matter how low I pointed the nose so I went back on >>> the mains and completed the flight. I shot some sun lines as I >>> approached Flores and hit it right on ETA. Then continued on and >>> landed at Santa Maria about fourteen and a half hours after departure. >>> >>> There was no excitement on the 800 NM leg to Porto Portugal or on the >>> leg across the Bay of Biscay to Nantes or on the last leg into >>> Brussels. >>> >>> After this they built a frame to hold the ferry tank about two feet >>> above the floor and no more problems on later flights.." >>> gl >>> >>> On Jun 11, 8:21 am, Gary LaPook wrote: >>> >>> >>> >>>> I guess it all depends on your perspective. I have flown across the >>>> Atlantic in a plane as small as a Cessna 172, single engine, four >>>> seats, (and had the engine quit a number of times in the middle of the >>>> ocean in the middle of the night, whew!) while using my trusty A-10A to >>>> shoot stars and the sun in order to find Flores in the Azores so as to >>>> be able to refuel. >>>> >>>> gl >>>> >>>> douglas.de...@btopenworld.com wrote: >>>> >>>> >>>>> Regarding Sir Francis Chichester: >>>>> >>>>> Dr. Kolbe has it right. >>>>> >>>>> I was referring not his astonishing navigation for which I have the very highest regard indeed, but to the fact he was willing to put his life on the line with an aeroplane that he describes in his book already had various problems such as having fitting floats without checking if they leaked or not, and an engine that had already given him problems, and in the run-up check before leaving for Norfolk Island he says:- >>>>> >>>>> "I could only get 1780 revs, forty less than I expected, and my spirits sank. I should never get off with a full load with a motor like that, but said nothing to the CO about it. The seaplane was launched. I faced her into the wind, and opened the throttle; to my surprise she left the water as easily as a sea bird..... ". >>>>> >>>>> The man must have been mad or very determined, or both. >>>>> >>>>> To cross the Tasman Sea - a nasty stretch of water notorious for bad weather, two thirds the width of the Atlantic, in a single engined float plane with engine in dubious condition is more than reckless. But got away with it. >>>>> >>>>> My impression from reading his books is he was what we would call a "loose cannon" and contemptuous of any advice or authority. From reading about him it seems he must have been a truly remarkable person but not very 'likeable'. >>>>> >>>>> Douglas Denny. >>>>> >>>>> Chichester. England. >>>>> >>>>> >> >> > > > > > > --~--~---------~--~----~------------~-------~--~----~ Navigation List archive: www.fer3.com/arc To post, email NavList@fer3.com To unsubscribe, email NavListemail@example.com -~----------~----~----~----~------~----~------~--~---