Kurt Sensenich, from philly.com takes a helicopter lesson from Eagle II Aeronautics

Flight planning. Because of the internet, it’s easy to flight plan properly. There are several excellent weather sources. I use NOAA’s ADDS. NOTAMS should be checked—they can be consulted in seconds at the FAA’s website. Nowadays, we need to check for TFR’s, which is easily done at AOPA’s site.

Aircraft pre-flight. Get in the habit of doing this slowly and methodically. The pre-flight is also called a “walk-around”—for good reason. Always begin in the same place and make your way around the aircraft. If you are interrupted, be sure re-start where you left off. If you’re not sure where you left off, start over.

Checklists. We emphasize the use of checklists at our flight school. In Part 91 operations, you can make up your own checklists. You’ll want to begin with those supplied by the manufacturer in the operating handbook or flight manual, but you can change these due to modifications or equipment additions to your aircraft. Checklists aren’t just for beginners. In fact, as you acquire more experience it is likely that you’ll be qualified on multiple aircraft, and this is when you really need checklists.

Clearing on the ground. Before you move an aircraft, clear visually. In an airplane, this includes looking at where your wingtips are going. In a helicopter it means checking that the skids are free to move—and clearing all around and overhead before picking up into a hover. Also in helicopters, always clear the tail before making a pedal turn. I tell my students that someday in their career they’re going to look before moving the tail, and there is going to be a human being beside the tailrotor.

Clearing in the air. Before making a turn, habitually look in the direction of the turn. Sounds like common sense, but I’ve flown with people who don’t look.

Pre-landing checks. These will depend upon what you’re flying. Obviously, retractable gear aircraft have a lot potential for embarrassment. Airplane pilots use the time-honored “GUMP” check: gas, undercarriage, mixture, prop. At the airline, in addition to completing the official landing checklist, I recite four “landings” to myself on every approach: “landing gear”, “landing flaps”, “landing runway” (as in the correct one), and “landing clearance.” This isn’t found in any airline checklist or policy; I made it up.

Ignition switch – “off and out”. So many people have been killed or maimed by propellers attached to piston engines whose magnetos were thought to turned off. If you make a habit of removing the key from the ignition switch after shut-down (and incorporate this in your written checklist), you will have insured that the mags aren’t hot. (Well, not exactly—the mag switch could fail hot. So don’t ever place yourself, or let others put themselves, in the propeller arc.)

This is only a partial list of good habits. The continuous discipline of building good habits is a halmark of the professional aviator. If you’ve been flying for any length of time, you’ve probably already developed some of your own. (Please share them in the Comments below.) 

Economics. Avgas production peaked during World War II and was robust into the 1950’s, when airline fleets still consisted primarily of piston-powered airplanes. However, avgas now comprises less than 0.5% of the production of all transportation fuels and comes from only about a half dozen producers world-wide. In addition to poor economies of scale, aviation gasoline requires a dedicated transportation and delivery infrastructure—at no point in the supply chain can it be contaminated with any other type of gasoline.

Whereas avgas formerly was produced in multiple grades, according to octane rating, there remains only one available grade, 100 Low Lead. “Low Lead” is a relative term, as the tetraethyl lead (TEL) content—2 grams per gallon—is about four times the amount which was in leaded automotive gasoline before it was phased out. TEL is still used in automotive gasoline in a few countries and was used in NASCAR racers until 2007. Today only one firm in the entire world—Octal—produces tetraethyl lead.

Environment. In October, 2006, Friends of the Earth petitioned the EPA to require the elimination or reduction of lead from avgas. And in October of 2008, the EPA issued new standards which reduce allowable lead in the air to 1/10th of that allowed previously. Industrial processes probably emit much more lead than the exhaust from piston aircraft, but the possibility of high concentrations of lead in the air around busy airports opens another front on which environmentalists may attack the use of leaded avgas.

General aviation lobbies are arguing for a rational perspective on the leaded avgas issue. They point out:

• that the gross amount of aircraft lead emissions is small,
• that there still exists no replacement gasoline which can be used by the entire piston aircraft fleet,
• and that the sudden banning of leaded fuel will severely damage an industry that employs hundred of thousands of persons.

Nevertheless, it appears that the elimination of leaded avgas is not a matter of if—but when. How will general aviation respond? By convincing gasoline producers to replace 100 Low Lead with a product that is basically premium auto gas, without ethanol, and with strict quality control. Operators of low performance and high performance piston engines will be affected differently.

Low performance. Aircraft with low-compression, non-turbocharged motors probably will be able to use this fuel without modification to airframe or engine. It will require Supplemental Type Certificates for both engine and airframe, and the respective  manufacturers will have to get on-board with this if they want to stay in business. Lycoming already has indicated that this is a solution they want to support. Presumably, Continental will follow suit.

High performance. The solution for high-compression or turbocharged installations probably will involve electronic management of mixture strength, spark timing, and manifold pressure. Obviously, retrofitting this kind of system will be very expensive.

I plan to post another article on aviation fuels next week. Meanwhile, something I’ve experienced …

MY STORY: Years ago when I was a research engineer at Lycoming, my boss walked into my cubicle and said, “I’ve got something for you on the loading dock.” What he had were two 55-gallon drums of Soviet aviation gasoline. Piper was selling Navajo Chieftains to the Poles and told them that it would necessary to qualify the engines on their fuel—and that Piper would need some of that fuel for testing.

Well this was during the Cold War, and no Communist functionary was going to risk his neck by giving out samples of, or even information about, aviation gasoline. But Piper knew that the results of running highly-turbocharged engines on what was probably a lower-octane fuel could be disastrous.

What to do? Smuggle it! And that’s what they did—sort of. In the course of negotiating the sale, Piper made several trips from West Germany into Poland. They flew in Navajos, which have two fuel tanks in each wing. They would arrive at their destination with empty outboard tanks, purchase fuel, and have it pumped into those tanks. In several trips they accumulated about 100 gallons, which made its way to our loading dock in Williamsport, PA.

Our main concern with this fuel was detonation, or “knock”, and we suspected we would need to modify the operating limitations to run on Soviet fuel. We put a Navajo engine on a dynamometer with detonation sensors and two fuel supply systems—one for 100 Low Lead and one for the Soviet gas. We would warm up the engine on the 100LL and make it detonate by increasing manifold pressure, switch over to the other fuel, and make it detonate again.

We did this many times, at various simulated flight conditions (always with an eye on the Soviet fuel remaining). The result was a modification to the flight manual with lower manifold pressure limits. I also wrote an SAE Technical Paper about it.

Use of automotive gasoline. Auto gas can be used in many low-performance aircraft engine installations. This is done through the process of obtaining a Supplemental Type Certificate, or “STC”, for both the engine and the aircraft model. Such STC’s have been granted by the FAA, but the major engine manufacturers, Lycoming and Continental, both have issued statements recommending against the use of auto gas in their engines. In addition, a current trend is making the use of auto gas in aircraft very problematical—the inclusion of ethyl alcohol, which can damage current fuel systems and engines. Many states are requiring ethanol to be added to auto gas, and general aviation lobbies are seeking legislation requiring the availability of at least one grade of auto gas which remains alcohol-free.

Development of an ethanol/gasoline avgas. Despite the problems with using alcohol in aircraft, the University of North Dakota, with funding from the South Dakota Corn Utilization Council and the U.S. Department of Agriculture, by 1999 had developed AGE 85, an unleaded aircraft fuel consisting of 85% ethanol. In 2002, Cessna Aircraft issued a service bulletin warning the owners of many of its aircraft models against using ethanol-based fuels—for several good technical reasons.

Development of 82UL. This is an unleaded fuel made from the same basic stocks as low-octane auto gas, but with higher quality control and without ethanol. It can be used only in low-performance engines and has not yet been placed in production. Like any aviation fuel, it would required a dedicated distribution system.

Lycoming’s Auto Gas Approval Program. Lycoming is the largest manufacturer of piston aircraft engines and is developing a process to approve their products to use a fuel based on unleaded premium automotive gasoline. It would not contain ethanol, would have high quality control, and would have its own distribution system. So far, this program is only for 360 cubic-inch engines of up to 8.5:1 compression ratios. Lycoming has not said what provisions will be made for engines with higher compression ratios.

This fuel issue will have a tremendous impact on aircraft operators. Right now I am considering the purchase of another helicopter for our flight school. One model under consideration uses a high-compression Lycoming engine, the other a low-compression version. I probably won’t buy the high-compression variant because I don’t know whether I’ll be able to obtain fuel for it.

Next week: more on aviation fuels.

This is the first of several articles I’d like to post on aircraft engines and fuels.

Turbine engines have become dominant in aviation because of their high power, low weight, and remarkable reliability. However, piston aircraft engines stubbornly retain a niche at the lower end of the power spectrum—below about 400 horsepower—and the reasons are less initial cost and relative fuel economy.

All engines produce power by doing three things to air (called the “working fluid” in thermodynamics): compression, heating, and expansion. In a turbine engine, compression is accomplished by a centrifugal or axial compressor, ignition occurs in a continuous flow in a combustion chamber, and expansion is through a turbine. In all cases, the turbine supplies power to drive the compressor. In the turboshaft engines used in helicopters and in turboprop installations in airplanes, designers try to extract as much energy as possible from the turbine—to turn a shaft.

In pure turbojet engines the turbine takes only enough energy to power the compressor and accessories; the rest is used to accelerate the working fluid and produce thrust. In a turbofan, such as this CFM56, much of the energy captured by the turbine powers a fan, which accelerates air that hasn’t gone through the combustion process. Today’s turbofans have very high “bypass” ratios—the proportion of fan air to combustion air.

Gasoline-fueled piston engines achieve compression in a cylinder, and heat is added at the top of the piston stroke by the combustion of a fuel/air mixture—initiated by a spark plug. Then expansion moves the piston, transferring power to a crankshaft. Diesel engines differ in that ignition is achieved through high temperatures produced by high compression (they are also called “compression-ignition” engines).

I believe that diesel engines, which can run on jet fuel, are the future for aircraft engines below 500 horsepower. The diesel is simpler, more reliable, and more efficient, but the issue which will really drive diesel development is the fact that the fuel on which most piston aircraft engines run has become so problematical. Our 100-octane, leaded aviation gasoline is going to disappear.

While the diesel may be the aviation piston engine of the future, there remains a worldwide installed base of about 300,000 gasoline-burning aircraft engines. Unlike automobiles, which are produced by the millions annually and last only about a decade, general aviation aircraft are produced in small numbers* and can last almost indefinitely. So we must resolve the issue of how to supply fuel for existing gasoline-burning aircraft engines. Let’s look at that subject next week.

*In 2005 only 2,465 piston airplanes were produced worldwide. (source: General Aviation Manufacturers Association Statistical Databook)

I have a personal interest in Pennsylvania’s aviation history and have learned that our Commonwealth has contributed much to the advancement of aeronautics. Here are some of the high points:

BEN FRANKLIN. Perhaps it should not surprise us that Benjamin Franklin was involved in the first aeronautics. On November 21, 1783, he was present for humankind’s first aerial voyage, when two Frenchmen cast off from Paris in the Montgolfier brothers’ hot-air balloon. Franklin’s enthusiastic correspondence with friends in Philadelphia helped make that city the ballooning capital of the New World; indeed the first recorded balloon flight in America occurred there in May, 1784.

JOHN WISE. In the first half of the 19th century, balloonists were known as “professors”, and preeminent among them was John Wise, born in Lancaster in 1808.  Wise’s career spanned 44 years and included one 20-hour flight of more than 800 miles—an astounding feat in the 19th century.

SAMUEL PIERPONT LANGLEY was Professor of Astronomy & Physics at what is now the University of Pittsburgh. He was avidly interested in the possibility of heavier-than-air flight and  researched, among other subjects, fluid mechanics, propulsion, and aerodynamic control.  In fact Langley was wrong about a lot of things, but he was a role model to the Wright brothers, who admired and emulated his methodical, scientific approach—which paid off for the men from Dayton. 

LYCOMING. In 1908 the Lycoming Foundry and Machine Company was founded in Williamsport. They began building automobile engines and by the 1920’s were supplying them for Cord and Auburn. During WWI Lycoming supplied aircraft engine components and by 1929 had developed their own complete aircraft engine, which was an immediate success. Today, Lycoming is the largest builder of piston aircraft engines in the world.

NC-4. When asked who was the first to fly across the Atlantic, most people would say “Lindbergh”. But this is not true; he was the first to fly it solo. The first to fly the Atlantic were a Navy crew in the Navy/Curtiss flying boat, in May, 1919. The Navy/Curtiss design was a cooperative effort between Curtiss Aircraft and the Naval Aircraft Factory outside of Philadelphia. 

STANDARD PROPELLER. In 1919, two Westinghouse tool designers, Thomas Dicks and James Luttrell, designed a new steel propeller and founded the Dicks-Luttrell Propeller Company in Pittsburgh. This became Standard Propeller and then Hamilton-Standard, which developed into the largest propeller maker in the world. Today it is part of United Technologies. 

PIPER. Perhaps the best-known Pennsylvania aircraft manufacturer is Piper. In 1929 residents of Bradford, PA, enticed the three-year-old Taylor Brothers Aircraft Company to move from Rochester, New York, to Bradford. In 1930 William T. Piper, a successful oil-man who served as the corporate treasurer, bought out the struggling company. It was re-named Piper and moved to Lock Haven, growing and prospering under Piper’s leadership—even through the Depression. The company continues to produce aircraft today in Florida. So successful was Piper in bringing airplane ownership to thousands of pilots that even now the generic name many people use for a light airplane is the “Piper Cub”.

SENSENICH PROPELLER. Harry and Martin Sensenich, two Lancaster County farm boys, got into the propeller business after they cracked up their airplane-engine-powered ice sled and had to make their own replacement propeller.  In 1932 they formed Sensenich Brothers to manufacture propellers, and employment at the company during WWII peaked at 400 persons. Sensenich still produces propellers in Lititz. 

FRANK PIASECKI, a University of Pennsylvania engineering grad, in 1943 organized an engineering firm and designed and built a single-rotor helicopter. However, Piasecki’s real interest lay in the tandem-rotor concept, and by 1945 he had built his first example.  This is an early military model. Tandem-rotor helicopters are manufactured today in Delaware County by the Vertol Division of Boeing, to whom Piasecki sold his company. 

NARCO. In November, 1945, three entrepreneurs formed the National Aeronautical Corporation, or NARCO, to produce aircraft radio equipment. They began in the back room of a store in Collingswood, New Jersey, and shortly thereafter moved across the Delaware River to Philadelphia. Today, NARCO is in Fort Washington, still making reasonably priced avionics for light aircraft.

How can you do this? Perhaps be an unpaid assistant at an aircraft maintenance shop. If they have flight operations, they might even trade some flight instruction for your hours. And if you own an aircraft, try to set up an “owner-assisted annual” with your maintenance provider. Especially with small airplanes, the annual inspection is when most maintenance gets done. “Owner-assisted” means you do the grunt work under the supervision of the mechanic who is administering the inspection. You’ll save money on maintenance and get a great education.

MY STORY: I got interested in aviation through mechanics; airplanes were the next step after fooling around with other machinery. When I was about eleven, my Dad and I acquired a homemade go-kart powered by an old lawn mower engine, and this became my research and development vehicle. Fortunately there was a test track nearby in the form of a dirt turn-around, used by tanker trucks at the local heating-oil company.

One product of this youthful engineering was a motor scooter made from a bicycle frame. Powered by a noisy high-revving 2-stroke lawnmower engine, it had a three-speed gearshift hub from an “English bike” and was frighteningly fast. However, those hubs weren’t designed for that much power, and the lifespan of their innards was about a day. I kept the scooter running because of the kindness of a bicycle-shop owner who let me rummage through his junk bin.  I think he charged me a dime for a hub.

The last version of our go-kart used the same engine, and when my Dad wasn’t looking I would drive it in the road. Well, a junior-high coed named Ellen lived up the street, and one day I passed her as she was walking home. After stopping to talk, I ran the kart up the road and came back at full throttle, hoping to impress her. The 2-stroke engine was really singing, and at the instant I passed her it exploded, spewing metal all over the place. Having built up a lot of speed and being too embarrassed to stop, I just coasted home. Apparently none of the shrapnel hit Ellen, because she never mentioned it, and I certainly wasn’t going to bring it up.

The cockpit of a helicopter may be the ultimate multi-tasking environment. There’s a lot of stuff going on, and I like to think of it in three categories: physical, sequential, and strategic.

Physical-the manipulation of the controls: Hovering a helicopter is an example of a physical activity. No amount of ground school can teach you to hover; you’ve got to find an instructor with calm nerves, climb in, and do it.* There’s no short cut; it just takes a certain number of hours to train your nervous system to hover.

Sequential-the order in which control applications are accomplished: An example of a sequential activity is taking off from a hover. At our flight school, in the Schweizer 300, we teach it as follows:

• Apply gentle forward cyclic until above ETL (effective translational lift).
• Then apply more forward cyclic so that the forward edge of the rotor disc appears to be at the end of the runway.
• Accelerate to 40 knots; then apply aft cyclic to assume the climb attitude.
• Adjust manifold pressure to the value required for hover.
• Adjust pitch attitude to maintain climb speed.

Strategic-the big picture: Approaching a tower-controlled airport is a strategic exercise. Let’s say you’ve listened to the ATIS (Automatic Terminal Information Service) and have made initial radio contact with the tower. Now you’re asking yourself some questions. From what direction are those winds? What kind of traffic pattern did the tower say to enter—and for what runway or landing zone? How will I get to my desired location on the airfield after the approach? How strong are the winds? Will they be a problem if I have to hover downwind? While you’re thinking about all this, you’re accomplishing the physical manipulation of the controls and the sequence of actions required to descend to the airport—but because you practiced these things, they’ve been relegated almost to the sub-conscious.

Chair Flying. This brings us to a technique I’ve used throughout my flying career. Chair flying is the poor man’s simulator and is very useful in preparing for sequential and strategic activities. You literally sit in a chair, close your eyes, and mentally walk through a sequence or scenario. For example, before a lesson which includes taking off from a hover, I’ll ask the student to memorize the steps. If they do, they’ll be able to focus on the physical manipulation of the controls while mastering this task during the flight.

If they don’t memorize the steps beforehand, they’ll try to learn them as we fly—and probably will get way behind the aircraft. Then we’ll have to make several more traffic pattern circuits to learn the sequence. So, the time to learn the sequences is not when you’re paying several hundred dollars per hour in the helicopter; the time to learn them is at home—for free!

Chair flying also works well for the strategic. Before flying to a tower-controlled airport, the student should preview the whole scenario. By anticipating the factors they will have to deal with, they’ll be able to stay ahead of the helicopter—even when thrown a curve by the tower or other air traffic.

*MY STORY: An author and motivational speaker named Charlie Jones has said, “There’s no humility without humiliations.” I first flew helicopters in the Army National Guard, who set up a local helicopter qualification course for former military fixed-wing aviators. All the instructors had a couple of tours in Viet Nam and had been instructor pilots on active duty. It was the best flight training I’ve ever had.

I was in a class of five: two Army pilots, one Navy fighter pilot, another Air Force fighter pilot, and myself. When our instructor, Chip, took us out on our orientation flight—our “dollar ride”—in a UH-1 Huey, the first victim he selected for the pilot’s seat happened to be the least current in flying, but it didn’t matter. Chip picked the thing up into a hover—surrounded closely by other Hueys on their pads—and handed the controls to the student, who promptly got us into an extremely unusual attitude. To our relief, the instructor grabbed the controls, took off, and got far away from the airdrome before letting victim No.1 touch the controls again. (Later Chip said, “I saw parts of the attitude indicator I haven’t seen in years!”)

We all took turns flying in cruise, which was sort of like flying an airplane—not so bad. But then we returned to the base (way out in the grass where we could harm only ourselves), cycled though the hot seat, and tried to hover. Well, we all gained some humility that day.

If you learn to fly helicopters, down the road you’ll wonder what was so hard about hovering, and you’ll do it almost unconsciously—with little more effort than riding a bike. When I started flying helicopters, I thought I was a pretty hot pilot, but I can tell you that it doesn’t matter what you’ve flown or how good you are—trying to hover a helicopter for the first time is a humility builder.

I love instrument flying. The first time I broke out of the clouds on a real instrument approach and saw the runway, it was as thrilling as first solo. Having an instrument rating in your resume is becoming a must as you apply for the better helicopter flying jobs.

The FAA Instrument Rating Practical Test Standards (FAA-S-8081-4E) says, “Examiners should determine that the applicant demonstrates competency in either the PRIMARY and SUPPORTING or the CONTROL and PERFORMACE CONCEPT method of instrument flying.” The FAA Instrument Flying Handbook (FAA-H-8083-15A), in Chapter 4, Section I, describes and recommends both methods.

I’ll admit my bias toward the Control and Performance method. I learned instruments this way in the Air Force and didn’t know there was any other method until I was exposed to Primary and Supporting in general aviation. For a long time I thought that this method, which requires memorizing which flight instruments are “primary” and “supporting” in various regimes of flight, was really nutty. However, the reason for it finally dawned on me: in the past most general aviation airplanes had unreliable, unstable vacuum-driven attitude indicators. Probably for this reason, the Primary and Supporting method has you looking at just about everything but the attitude indicator in most phases of flight.

In contrast, the Control and Performance method teaches us to focus on the attitude indicator most of the time, making only visual excursions to other instruments. It’s a hub-and-spoke concept: the attitude indicator is the hub, and when our eyes go out to another instrument, they should go back to the hub before going out on another spoke to a different instrument. I teach students to look at another instrument only briefly—and then go back to the attitude indicator and think about what they saw.

At our helicopter flight school, we teach Control and Performance for these reasons:

• It’s much easier.
• It produces a safer, more precise instrument pilot.
• It lays a foundation for flying instruments in higher performance aircraft.
• Any helicopter certified for instruments is going to have a quality, stable attitude indicator.
• Our instrument trainer has a quality electric attitude indicator that is very stable.

OK, let’s really define Control and Performance. “Control” means there are two instruments that display our control inputs. One is the attitude indicator, which may be a self-contained gyroscopic instrument or a display that gets information from a remote source. In any case, this instrument displays the pitch and roll inputs we make with the cyclic.

The other Control instrument displays power inputs made with the collective/throttle. This is the manifold pressure gauge in a piston helicopter, or the torque gauge in a turbine. Everything else—airspeed, altitude, vertical speed, heading, and rate of turn—are the results of Control inputs; they are the “Performance”.

The neat thing about Control and Performance is that you don’t have to memorize much. We teach only two pitch attitudes (in degrees relative to the horizon) for all our instrument training—one for climb and another for level flight and descent. (OK, a third for autorotations—a real hoot on instruments!) We teach four manifold pressures: climb, level flight, normal descent, and rapid descent. For example, for a 500 feet-per-minute descent on a non-precision approach we maintain -6 degrees of pitch on the  attitude indicator and set 21 inches of manifold pressure. Our helicopter then performs a stable descent at 68 knots. 

With this method, by memorizing only a few numbers, you can pass every instrument check ride through the ATP. I strongly recommend making Control and Performance the basis of your instrument flying skills. It will help you master instruments in helicopters more quickly and, as you progress in your career as an aviator, will lay the foundation for instrument flying in any aircraft.