The Pilot’s Lounge #135: Think You Fly IFR? Meet Dave Hertel and Friends at the Hump


In the Pilot’s Lounge here at the virtual airport, the weather has been just plain foul. Our instrument-rated pilots have had the chance to shoot approaches pretty close to minimums. Talk has been an interesting juxtaposition of IFR procedures tied in somehow with the exploits of World War II bomber and fighter pilots who got the press and glory. It got me to thinking about the fact that weather in World War II would regularly get every bit as rotten as it does now and that the vast majority of daytime combat missions would be launched only if the weather forecast for the target area and the return was suitable for visual flight, especially as many of the fighters did not have the capability of making an instrument approach back at base. Yet, unsung and often ignored, those who were flying the transports to supply the glory boys in the fighters and bombers were routinely flying in the weather that grounded combat operations. And I thought of my good friend, Dave Hertel, of Grand Rapids, Michigan, now in his 80s, and compared his instrument operations in the 1940s to that of today, for I am afraid we have become complacent … .Today we rise from the earth in our machines, navigate using some of the most sophisticated technology known, and let down to a point 200 feet above the ground, when visibility is merely a half mile, spy a runway and alight upon it. Almost without exception, we then congratulate ourselves for our skill and daring without considering that the boxes on the panel will take us by the nose and lead us to the runway, and that any failure to arrive at the desired location is, in truth, probably because we err. To top it off, most of us proceed to pat ourselves on the back the moment the mains touch, because our machines have the steering gear in the front so, even on a windy day, it takes a feckless dolt to lose control once rolling along the ground.We may have become proud and thus perhaps test the patience of the gods aeronautical. I suggest we remember those who preceded us in the skies and maybe acquire a bit of humility in the process.Dave Hertel and his Army Air Force compatriots based in India provide sterling examples of members of our fraternity flying regularly in truly awful instrument conditions every single day while sometimes being shot at. As humble seekers of knowledge it might do us well to tread among those giants of a prior generation and listen to what sort of instrument flying they did, and learn from it.World War II was well under way, and events and a determined enemy had conspired so successfully that the Allies fighting in China found themselves in the position of having to obtain virtually all of their supplies via airplanes if they wished to continue hostilities. Despite the remarkable advances in load-carrying ability of airplanes since the days of the Wrights, supplying a military operation via airlift had never been successful. The logistics of supplying a large group of people who both desired to eat and hurl mechanical invective at an opponent were simply staggering. Needed material was measured in thousands of tons per day in a time when few of the transports in existence could even carry ten tons of payload. The Army pilots also faced an additional, niggling variable: they would have to cart all of the needed bits and pieces over the highest mountain range in the world, itself a generator of some of the meanest weather imaginable.In almost British understatement, the air supply line to China became known as the "Hump." Peaks forced enroute operations to take place at a very minimum of 15,500 feet above sea level. The sheer magnitude of material to be carried required that airplanes arrive at each of four Chinese airfields every few minutes, around the clock, month after month. Air Force General Tunner organized and commanded this aeronautical nightmare with such success that he would be called upon a few years later to do it all again when he set up the Berlin Airlift, a virtually identical operation that received far more publicity yet operated in less taxing circumstances.Imagine, if you will, that you are Dave Hertel, or one of the other pilots who, as did Dave, spent most of 1945 and 1946 coaxing massive Curtiss-Wright C-46 Commandos over and between the giant rock piles of the Hump. Take a long moment to start your consideration by recognizing that the C-46 was the largest piston twin ever, bigger even than a number of four-engine airplanes, such as the B-17 Flying Fortress. Then let it sink into your aeronautical soul that you had yet to turn 21 when you ferried a brand new C-46 from the U.S. to Mohanbari, in the Brahmaputra River valley of eastern India, via the Caribbean Sea, South America, the Atlantic Ocean, with a fuel stop at Ascension Island, and thence across Africa and a big slice of Asia. Mohanbari was one of several air bases set up as cargo hubs where surface transport brought the multitude of things to be stuffed inside C-46s, C-54s (which later in civilian life became the DC-4) and bastard variants of the very fine B-24 Liberator bomber known as the C-87 and C-One-Oh-Boom (C-109 aviation fuel tanker). A bit more than 500 miles to the east, on the Yunnan Plateau of China, were the four bases to be supplied.On this summer evening, you get the call to haul some 20 hours since your last endeavor. You mutter a bit because 16 hours is about the average interval between flights, so the weather in this monsoon season must be especially foul for things to have gotten backed up enough to give you some extra sack time. You get a weather briefing, on which you rely because it comes from reports of pilots who are right in it, and a load manifest, which you consider cheap fiction. You are probably going to be well over gross because cargo weights are estimates and, in your experience, lousy ones. In monsoon season, with its broiling heat and thunderstorms, the preferred cargo is avgas. While it can prove pyrotechnical if a Japanese fighter takes an interest in you, at least a 55-gallon drum of avgas always weighs 330 pounds, the ground crews have been given orders as to the maximum number of drums they can shove into the airplane, and most can count, so, carrying avgas, you will only be at gross weight. You learn that your cargo is not avgas so you and your copilot make some not so funny jokes about how good the loaders are at stuffing 10 pounds of, ahem, stuff, into a 5 pound bucket. As usual, you have full tanks, 1,400 gallons, because you won’t be given any fuel in China and, if the weather is good enough, some of your fuel load will be considered part of what you are supplying your comrades in arms and drained while on the ground at your destination.Tonight you are going to Kunming where there are clouds reported at 1,000 feet with about two miles visibility. That makes things marginal, for 1,000 feet just happens to be the minimum descent altitude due to the mountains near the airport. You take a moment to consider the fact that Kunming is at about 6,000 feet MSL, so even with 3 hours of fuel burned, a missed approach in the heat of a summer night means doing everything right to avoid the tall stuff, despite the initial part of the procedure being over a large lake. Here at home plate, it is raining torrents. The cloud base is high, but visibility is only about a half-mile. Technically that’s less than minimums for the NDB approach, but you’ve heard a half dozen Commandos land just since you got the call for your trip. At the Hump, if you can’t track 2.5 miles outbound from an NDB in a crosswind and find a runway during heavy rain, you need to go fly something easy, like fighters.Once in the airplane you start engines and immediately check to see that the ADF is pointing in the correct direction, as it is your sole navigation radio. When you, the copilot and radio operator are satisfied with everything, you feel your way to the runway. Though it’s not long since you were a teen-ager, you know the Commando’s foibles and taxi the beast with differential power and very occasional taps on brakes you consider hopelessly inadequate. You take a moment to again curse the engineer who decided not to put a steerable tailwheel on the world’s largest twin-engine airplane. Your friends flying the smaller B-17 at least have an aircraft that is easy to handle on the ground.The Army guys in the tower confirm your route clearance and your altitude, which is dictated by your destination. There are four Chinese bases and four altitudes eastbound for C-46s, a thousand feet apart, from 15,500 through 18,500 feet. You wouldn’t mind being in a C-54 because they get the next 4 altitudes with more breathing room above the boulders, and they are heavenly flying airplanes; however, you are very glad you aren’t in those pig Liberator conversions that get assigned to the high 20s for cruising altitudes as they take forever to get there and fly as poorly as they look. Precisely on the appointed minute, tower clears you to roll; something you and your loaded steed proceed to do for quite some time. Eventually you wallow noisily into the air, and transition immediately to instruments while being mildly curious as to how far over gross you are tonight as you tell the co-pilot to retract the gear and set max continuous power. You are thankful that this time at least the c.g. is probably close to the published range because you are not wildly out of trim as you settle in and thunder upward through the fire-hose intensity rain.As captain, you will do all the flying, unless the autopilot decides to crap out. If it does, you’ll let the aeronautical child in the right seat fly some during cruise, but never on takeoff, approach or landing. It is Army policy that you in the left seat are the brains of this operation, will do the flying and the kid (even if he is older than you) will sit there, be quiet and do as he’s told.You point the airplane at the first NDB, Moran Beacon, and climb for all you are worth. Occupying a prominent place on the panel before you, the Bendix ADF needle will point unerringly at Moran unless there are thunderstorms in the area, such as there are tonight. As usual, they are just past the beacon, piled up along that first ridge of the Himalayas, dumping moisture and promising you blinding lightning and hard work for the first 20 or 30 minutes after you pass Moran and have no choice but to get in among them. However, that is in the future, right now you are nearing the beacon and it’s time to be thinking about setting up the racetrack climb pattern you will have to use, because you don’t dare proceed further until you have attained no less than 14,500 feet. Drifting away from the climb pattern is not conducive to longevity as that first ridge alone tops out at some 13,000 feet.Passing through 14,500 feet you confirm that the ship is still climbing in a satisfactory manner even though you have already begun collecting that gift of summertime on the Hump – ice. The lapse rate means you will get ice so long as you are in the clouds and, based on your knowledge of the route, you figure you’ll be in the soup another 30 minutes, so you’ll get several inches of material you would much rather be putting in drinks. With the boots and everything working, you’ll be okay if the downdrafts in the thunderstorms are not too persistent. You tell the radio operator to report Moran to ATC, because each NDB on the Hump is a mandatory reporting point, and to give your estimate to the next one. The thunderstorms are there, big as life, so you crank up the cockpit lights to full bright to reduce the time you can’t see anything following a nearby bolt of lightning and slug it out with the hammering turbulence while confirming that the boots are keeping the ice under control. In winter ice isn’t much of a problem at the altitudes at which you operate, but summer means the icing level will have moved upwards to where you are to cruise. Add the soaked-sponge moisture of monsoon season and the recipe couldn’t be better for serious clear and rime ice. Tonight the boots handle the wings, but the alcohol on the windshield is worthless, as usual; it’s going to be opaque until well into the descent for Kunming.At 17,500 feet you level off and have the co-pilot set cruise power. Everyone flies the same power setting for cruise, which generates more or less the same TAS, depending on how heavy each airplane is and how badly it has been twisted and beat up. There is a C-46 ten minutes ahead of you at this altitude and another 10 minutes behind. Even with some discrepancies in cruise speed, it has proven to be adequate separation.The next NDB is over 100 miles ahead, so you will track outbound from Moran for some time before tuning in the next and proceeding to track it inbound. You consider heading something to be held within a degree or so, as only a very few degrees of error can put you into the rocks. You have become a master of mental arithmetic when tracking to or from an NDB, while somehow accounting for the erratic needle swings due to lightning. The science of navigation sometimes becomes art, but Dave Hertel and others on the Hump can conduct this symphony as well as any instrument pilot in the world.Past the boomers the ride smoothes out and you emerge from the side of the last cumulonimbus to look down on a solid stratus deck. In the moonlight the haunting vision of rocky peaks appear to each side of you, many going far above your altitude and you wonder if anyone will ever climb that peak well to the northwest of you called Everest, which you know is over 28,000 feet high.Approaching Kunming you let down to 10,000 feet and report the beacon outbound to Kunming tower. You then get cleared for the approach, descending to about 9,000 feet before starting the procedure turn. You’ll need to get down to 7,500 feet on the way back to the beacon, and be ready to lose the last 500 feet in the roughly 2.5 miles to the airport. You don’t wonder why they didn’t put the beacon on the airport; in fact, you can’t imagine such a thing. You’ve know that you need a solid final approach fix within a few miles of the airport so that you know precisely where you are before letting down, briefly, yes, briefly, to the minimum descent altitude.At 7,000 feet you see some lights on the ground, the ADF and directional gyro advise that you’re on course, and you know the area very well, so you decide to cheat a hundred feet. You’d rather not miss the approach; there is another airplane letting down about two minutes or so behind you, and you aren’t allowed another chance. If you do miss, you get to slog all the way home with the cargo still on board. Your copilot calls the runway lights and confirms that the gear and flaps are down, good lad, and you scrub off the altitude. You three-point the monster right on the numbers and feel your tension level rise because the airborne pussycat manners of the C-46 instantly turn sour once the tires start rolling. You don’t relax a bit until the aircraft is into the chocks and secured.After a visit to the latrine, some coffee and a chat with the weather folks, you head back out to the airplane. They, whoever "they" are, have defueled it to 600 gallons, total. You’re not crazy about that, because you suspect fog will be a problem when you get to Mohanbari about dawn, which means holding. You should have said something when you first walked into ops but it’s too late now, you are required to be in the air before an hour has passed.The return leg is longer than the outbound leg; it’s offset to the north, making a long, arc. It also has minimum altitudes that are 500 feet higher, but that is okay, as your Commando is a few tons lighter than it was an hour ago. Luckily, it’s not winter when you’ve personally experienced more than 100 knot headwinds on the return leg and can recall once taking exactly one hour and twenty minutes to fly the 120 miles between two NDBs.Over India, the eastern sky is getting lighter out your left window and you find that the monsoon thunderstorms have dissipated for a little while, something that gives you no joy whatsoever. You won’t have to wrestle your way through them, but it means Mohanbari is probably covered in ground fog. Sure enough, your radio operator hands you a note, the base is far below minimums, so it’s time to pull the power way back and mentally kick yourself for not hanging on to that extra gas. You enter a holding stack with a dozen other C-46s, orbiting and wondering when things will open up. Sunrise reveals a cloud deck barely 50 feet thick, right on the ground, as far as you can see. After about 15 minutes a C-46 with a qualified operations officer aboard arrives in the stack above you. He confers with the tower and then, exercising his prerogative, takes command of local air traffic control, something you hoped he would do.The airborne operations officer gets the tail numbers of everyone in the stack. He tells the lowest guy to shoot the approach and level off right on top of the cloud deck. From your perch, you watch the wingtip vortices of the olive drab C-46 make a furrow across the cloud before until the pilot starts a climb back to the stack . The ops officer already has the next Commando on the approach. That ship deepens the furrow. The guys in the tower have stepped outside and confirm that they can hear the airplanes going right over the runway. Two more airplanes make the approach. You can see the furrow widen and deepen as you work your way down the stack. Number five spots the runway and lands. That’s all it takes. Tower clears one of the waiting airplanes for takeoff and the ops officer runs the lot of you in just as fast as he can. The combination of landings and takeoffs keeps the air stirred up enough that the fog never closes back over the runway, and eventually burns off altogether. By that time you’ve parked the behemoth for which you are responsible. Before you can even get out, the fuel truck is there and the loaders have the first forklift up to the doors.You will keep doing this, in all weather, into 1946 because the end of the war doesn’t end the demand for supplies, it takes time to spool it all down. You will successfully navigate to landings in visibility as low as a half mile using only that Bendix ADF, which you trust with your life. Its loop antenna, over a foot in diameter, is in a teardrop shaped housing that looks like a cancerous growth on the airplane. There is but one ADF in the airplane. If it fails when you are in the clag, you are absolutely, totally and completely hosed. Yet, at a time when your buddy flying Curtiss P-40s is putting up with an engine that often gets only 15 hours between overhauls, and you can never count on the heater or the autopilot working on a Commando, that Bendix ADF is the essence of reliability. It is so accurate that you are comfortable holding a course line through the mountains when tracking an NDB that is 100 miles away.You survive this adventure, unlike some of your friends. In the year 2002, you will read of the recovery, that year, of four men from the wreckage of a C-46 at the 15,650-foot level and wonder if you knew them. Later in your life you will fly using GPS for navigation and sometimes be curious just how you did what you did over the Hump and whether pilots who think of an NDB approach as an emergency procedure can ever be referred to as accomplished.

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