Regular or Hi-Test, Sir?
Nothing so useless in aviation as the runway behind you, the air above you, and the fuel in the truck
We have all heard how expensive flying is in the world outside the cozy confines of the United States. Or think we have. The truth? You have no idea … I certainly didn’t. But that’s a given. We’ll stipulate that you are, on the whole, going to pay many multiples of what we think of already as too much in the U.S. In Egypt, at 6th of October Airport, we paid the equivalent of $22 a gallon for fuel. There were some circumstances — to our surprise we had to call out the fuel guy on his day off — but out here there are always circumstances. By the time we added up all the fees — there are also always fees — the rough estimate came out to something like that $22 a gallon. I never wanted to do the calculation again. Not sure Adam did either. At future refuelings, I just watched him start to peel off sheaves of U.S. dollars — everyone wants dollars — and I turned my head and thought how generous of him to let me ride sidecar on his grand adventure. And then I tried to go to my happy place. I hope Adam has one.
So, we stipulate that if you have to ask how much it is going to cost, it is too much. But what I did not anticipate, even having heard the stories many times from other Earthrounders, was how difficult it could be fueling in this part of the world. Well, in almost every other part of the world. (Let’s also stipulate that if you are flying a jet, it is much easier, in fact, other than the cost, it is not much different from fueling your jet in Teterboro or West Palm.) Avgas is a rare thing in most of the countries we pass through. There is just very little general aviation and very little market for it. Chicken or the egg? I don’t know if more avgas would make possible more general aviation or if more general aviation would create a market for avgas. My guess is that there are so many other reasons why GA is grim out here that the dearth of avgas is more a result than a cause.
Finding Avgas
So, if you are burning 100LL, your options for airports are already very limited. India is a big country with its share of airports. We have been told from reliable sources that avgas is reliably available at only four airports in the entire country: Ahmanabad, Nagpur, two of our stops, and Mumbai and Kolkata, neither of which are particularly friendly to GA. That leaves a lot of dry territory. (Our new friend Jaimesh tells us that he can arrange to have avgas shipped to other airports and I don’t doubt that he can. But that is new information to us and I don’t think that could happen through regular channels.) My point is just that there are so many places we would like to visit — and that tourists and travelers do visit — that are off the table for us because we can’t get fuel there.
So we start with the understanding that you have to pick your route based on where you can get avgas. (If you are bringing your jet, this doesn’t apply. Lucky you.) Add that to the ruinous cost and you may already be realizing that this could be a tough slog. But it gets more interesting.
There is also the issue of language. At Heraklion on Crete, we had to fuel from a stationary pump and the woman fueling us spoke absolutely no English. We needed a specific amount of fuel put in specific tanks — this airplane has four tanks. We tried to convey to her how much we needed, but the confusion was rampant. All we had to do was watch the meter, eh? Well, I did, but the meter seemed to be moving very fast, even for liters. We finally figured out that it metered tenths of a liter. More math to get the right amount in each tank. We came close.
Multiply by 3.785 or Multipy by .264
And the question of units. Avgas outside the U.S. is mostly measured in liters. 3.785 liters to a liquid gallon. So we are forever calculating our fuel load in gallons and translating our numbers into liters for the actual fueling. It’s simple arithmetic, but there is something about airplanes that makes simple arithmetic harder than it should be. I have seen bright young people with PhD’s in applied math get into an airplane and add three and three and get seven. Or worse, sixty. And we have made our errors. The problem is that too much fuel or too little fuel can be fatal in an airplane. Every calculation is one more possible point of error, one more place where the accident chain can take us off in a different direction.
See the Gimli Glider for a great aviation story and a cautionary tale with a happy ending. You can find the details on Wikipedia, of course. Look here for a dramatization, complete with the believable profanity of the pilots.
Never trust the gauges
And then there is the question of knowing how much fuel is in your airplane at any given moment. In N5831R we have four tanks. Two main wing tanks, just as Beechcraft built the airplane in the 1980s. We also have two huge, special purpose tip tanks purchased by Adam from a gentleman who had already taken them around the world once. These are typically known as Dolly Parton tanks because of their size and shape. They hold more than 80 gallons each, more than the total usable fuel in both wing tanks. They were constructed years ago from old military drop tanks and they are a story in themselves. Again for another time. So we have four different fuel gauges and a fuel totalizer in the airplane. There are errors in the gauges although much effort has been expended to minimize those errors. And the main wing tanks cannot be measured with a dipstick because of the shape of the tanks in Bonanzas and Barons. We know that the totalizer is very accurate, registering how much fuel has flowed to the engine — but it is not a gauge of the tanks and if we use its information to compute the fuel remaining our calculation is only as accurate as our assumption of the fuel with which we began. The possibilities for error are numerous — although many of them would result in relatively minor miscalculation. Some, however, could be calamitous. One of my few real concerns about this many-legged trip has been the possibility of a serious fuel miscalculation. Too many hours over too much water and too many inhospitable countries and too much inhospitable terrain with too few suitable airports. Too many flights that really need to begin where they begin and end up where they are supposed to end up.
We in the U.S. are accustomed to landing, having the fuel truck ease up to our aircraft, having someone fill up our tanks to our specifications — the only question is which tanks and how many gallons. If we have to taxi to a fuel pump, we feel as if we have had to make an extra effort. It gets a little more complicated out here. Some of the airports do have fuel trucks. Biggin Hill outside London, Dubrovnik, Luxor, and a few others had fuel trucks. Other airports had avgas, but only from the barrel, sometimes I suspect because they had very little traffic at all and in other cases because they have a great deal of traffic — jets. For instance, the airport at Abu Dhabi, part of the United Arab Emirates, probably the second wealthiest nation on earth per capita, had avgas only in barrels. When you can fly a Gulfstream, who wants gasoline?
How Many Drums Today?
Not that much of a problem, you say? Just put the barrel in the truck and tote it out to my airplane and pump me some gas. You wish. First of all, at some, maybe most of these airports, you have to pre-order the fuel so it can be brought to the airport for your departure. Most of the time, no one wants to fuel on your arrival, but would rather do it on your departure, which means one more delay on your departure, which is a complicated process at best. And those barrels? It’s not, “How many liters would you like, sir?” It’s “How many barrels?”
The barrels are the equivalent of 55-gallon drums, in several cases shipped in from Poland, I noticed. So you are purchasing something like 205 liters of avgas — whether you need it or not. Need 225 liters? No problem. You just bought two drums. No problem, we’ll use it up eventually. Not unless you want to strap the drum to the wing and carry it with you. (There’s probably a deposit on the drum, like an old-fashioned pop bottle.) You need 225 liters for that leg of your flight to provide the adequate range and reserve you have carefully calculated. Any fewer and you are going in the ocean if you have miscalculated or the winds are not as forecast or you have a fouled plug or any one of the hundred reasons why we always fuel with a reserve — a term that I don’t favor, preferring to think of it as a margin of error — but that’s another discussion that will fall under flight planning for another time. Any more than those 225 liters and you are too heavy, above your maximum takeoff weight or above the weight at which you know your airplane will levitate and fly under the conditions — runway length and grade and winds and density altitude and required climb for the SID and charted obstacles — that you face. So, you buy two 205-liter barrels and you put 225 liters on board your airplane and you leave 185 liters of the most expensive avgas you have ever seen in the barrel on the truck for someone else to enjoy. Just the way it goes.
How do we avoid that calamity? By planning ahead very carefully. We plan two or three legs ahead so that, when we have the opportunity to buy fuel by the liter, we work out a careful calculation that will allow us to buy one or two barrels at each of the next stops and use all of each barrel. Sometimes it even works out that way. Except, the first time we had a series of flights where we were attempting to schedule our fuel such that we could take on full drums at each stop, we learned the hard way at Abu Dhabi that a 55-gallon drum, which should yield at least 205 liters, yielded 178 liters measured by the meter on the pump, which, we would like to believe is calibrated by some Department of Weights and Measures somewhere. We had planned on two drums, each 55 gallons of fuel. How naive. So, suddenly we had enough fuel for our flight leg, but we would be landing with less fuel than expected, putting us in a fuel status much as described in the above paragraph. We would need for our next leg, a little more than one drum, but much less than two drums. An inconvenient shortcoming because we now needed to call ahead, or rather have Eddie and Ahmed call ahead, and arrange for a second barrel to be trucked in to Ahmanabad, which would take a day. And a very expensive miscalculation because we would leave much of that second barrel behind — paid for. It further complicated the fuel situation at our next stop, Nagpur, where the fuel was also from the drum, but where our fuelers worked diligently to shake every last drop out of the drums. Much of this seems to come down to how hard we are all willing to work to get the fuel that we’ve paid for.
It’s now Tuesday morning. Adam and I spent the rest of the evening doing just the sort of forward fuel scheduling I have just described. Much more to say about all of this but it must wait. We are in the MJets lounge at the Bangkok airport, the Don Mueang airport, waiting for the mx director to get us a small part we need, and any moment we will, we hope, be aloft en route to Kuala Lumpur. I’ll go ahead and post what we have said so far and conclude the first opportunity. If this “pilot stuff” is of interest, please check back. Otherwise, we’ll move on.
So, we are together again. Now I am writing from the Dorsett Grand Hotel in Subang, essentially Kuala Lumpur. It is Wednesday evening. Much has transpired since Tuesday morning of the last paragraph, but let’s get back to the fuel planning challenge. Our flight yesterday and those next two legs to come are a perfect example Warning, you may find this cryptic and really boring so be advised we are going to continue to talk about pilot stuff for a while here.
Flight Planning is Flight Planning
Here is a thought that has occurred to me many times on this journey. Our flight planning is a little more complicated and the costs are higher and the quantities are larger, but the flight planning we do to get around the world without running out of fuel is no different than the flight planning that we teach our primary students planning a 50-mile student pilot cross country in a simple Cessna 152. We take into consideration a host of factors, plot out a route, calculate our ground speed and our fuel burn, add a reserve — I choose to think of it as a margin of error — and we fuel the airplane according to those calculations. Furthermore, we teach students to carefully monitor in flight any deviations from those initial calculations, primarily changes in their time between known and calculated checkpoints to confirm that all of the assumptions built into those calculations are holding true — and to make adjustments as necessary, up to and including landing early. We may be flying a thousand miles in a foreign country IFR at higher altitudes burning much more fuel and flying faster and higher with more instrumentation, but the principle and the process is the same. There are eternal verities in flying. The numbers may be bigger or smaller but out of gas is out of gas.
Warning: Arithmetic ahead
VTBD 108-82=26 WMSA 26+154=180-140=40 WADD 40+100=140-80=60 YBRM
Let me translate. This is my own personal notation. It is how for years how I have scheduled fuel on multi-leg flights where the options on the high and low side were limited for reasons of weight and range. Here we go … VTBD is Bangkok Don Muang airport. (There is a another Bangkok airport.) We landed at VTBD with 108 gallons, more or less as we expected. We estimated 82 for the flight to Kuala Lumpur (WMSA), landing with 26 gallons, a reserve of approximately two hours, quite adequate given the alternates and the weather. That’s where we are now. Our next leg, an eight-hour flight to Bali (WADD) will consume, we estimate 140 gallons. (Much calculation goes into that estimate, of course: flight time, winds, weather, power settings, mixture settings, best and worst case winds, altitudes, true airspeeds, oxygen availability, terrain, and a few other things. We come out of it with an estimate an the understanding that we would need to adapt and adjust it as we approach the moment of flight and even in flight if events are different than our assumptions — which they usually are, although we have become rather good at it.) So, 140 is our estimate. We would therefore plan to land at WADD (Bali) with 40 gallons, approximately three hours of fuel. Our minimum reserve (margin of error) is always 1 hour, but many factors can affect how much more reserve we require, and this leg is long, with many chances for the weather to change and much of it is over water. In WMSA we can purchase fuel from a truck in any amount, so we are free to take on 154 gallons for a total takeoff fuel load of 180 gallons. Why not take more? We know that 180 gallons keeps us at a weight where the takeoff is normal and we get reliable climb even in the beastly heat and humidity of Southeast Asia. (Yes, humidity also hurts engine and wing performance.) And 180 gives us a safe reserve, so why make the takeoff more challenging and risky if unnecessary? But here’s the rest of it. In Bali, fuel is available only in drums. We buy one. Or we buy two. Or three. Can’t buy a half a drum. We need at least 120 gallons to leave a safe reserve for the flight from WADD to YBRM (Broome Australia). But, here’s the great part, because of decisions we made several thousand miles previously, we can buy two drums and use them all. Remember, we are paying for the two drums, whether all of it goes with us in the airplane or some of it remains in the drum. Assuming 50 gallons out of each drum, we can use both drums fully. (40+100=140-80=60 YBRM) We can take off with an adequate reserve and still at a manageable weight. And, if we manage to reduce our consumption on some of the earlier legs, we can adjust it here at WMSA to make the future calculations come out as intended — or close enough. Which is exactly what happened. We burned only 77 enroute to WMSA, so we can fuel with 149 to bring us up to 180 rather than 154 — because we know we can purchase by the gallon here at WMSA unlike Bali.
So here we stand now after adjusting our equation for the actual fuel burn enroute to WMSA:
VTBD 108-77=31 WMSA 31+149=180-140=40 WADD 40+100=140-80=60 YBRM
We have set up the fuel schedule such that, even if our estimate of 140 for WMSA to WADD is off a little, we will land with an adequate reserve and the addition of two drums will both give us enough for the flight to Broome and keep us at a safe weight for takeoff. We have built in that margin be careful planning.
That said, I am recalling this in a hurry from notes elsewhere, so if you notice any error in my arithmetic, please post a comment or email me before 0400Z when we fuel tomorrow. You are checking the math, right? Oh, and remember, multiply by 3.78541 ….
