New Pilot

Sometimes you have to question authority.

Pilots sitting around the airport office shooting the breeze will nod in agreement when the comment is made that sometimes, you have to respond to the insistent voice on the air traffic control frequency, or on the telephone back at the home base, with the words "negative" or "unable." No argument will issue forth from the assembled aviators — saying no is tough, but sometimes you've just got to do it.

Now put the same pilots in the left seat of an airplane, with the engine running and the insistent voice directed at them, and a strange transformation often occurs. It seems that many pilots will put themselves in a difficult flight situation before they will say no to that voice of authority coming through the headphones, despite all that common-sense chatter back in the office. It's not a conscious process of surrendering one's judgment to a high authority, but rather a reflexive response to a command from a known and accepted, perhaps feared, power. Such blind compliance may be polite and deferential, but on occasion — such as when the pilot knows more about existing flight conditions than the commanding personage on the ground — it can also be dangerous. What a pilot discovers through experience, however, as confidence rises and the big picture comes more easily into focus, is that the controller is usually a pretty easy fellow or lady to get along with, and that the circumstances that created the problem were probably more flexible than the pilot had originally thought.

Several recent cases in which pilots nearly took on avoidable burdens come to mind. In all cases, save one, intentions were good on all sides, but what one party perceived as being in the other's interests wasn't.

Such was the case at the beginning of an instrument training flight to be conducted in actual instrument weather some weeks ago. The pilot of the privately owned complex single was at the hold line, meticulously performing engine and instrument checks. He was monitoring the tower but had not yet initiated contact. Suddenly, the tower controller called our number and inquired, in a seemingly urgent tone, if we were ready to depart. We weren't, but the radio call stampeded the pilot, who lunged for the throttle, gave it a blast, and rolled forward, mumbling "ready for takeoff" into the radio. We were cleared for takeoff and instructed to fly runway heading, maintain 3,000 feet. At this point, I interceded, motioning him to stop the airplane and pointing to the navigation radios, on which neither the frequency nor radial for our first approach had been set. I radioed the tower, "We will need a couple more minutes, please."

"O.K., no problem," came the reply. "There's a heavy Airbus on final, and I was just trying to save you a wake-turbulence hold." I thanked the man but said we still had some chores to do. We spent the holding time giving the approach procedure one last look.

Another example: The student pilot was returning to the home airport from the practice area on a busy weekday morning, intending to do two touch and goes and then a full-stop landing, when a pair of P-3 Orions from a nearby naval air station showed up on the scene for a session of practice takeoffs and landings. "Cessna One-Six Bravo, bring it straight to the numbers, cleared touch and go, minimum time on the runway, on the go make right closed traffic," barked an overworked voice. In dual sessions, the student and I had made numerous "short approaches" like the one now being requested but usually without a pair of four-engine sub killers swooping onto the scene. Alone in the trainer, the 20-hour student pilot wanted to refuse the clearance, but he also wanted to offer a constructive suggestion. He said he remembered something he had seen me do one day in the pattern and decided to give it a try. "Tower, how about a three-sixty instead?" he said. The controller approved the maneuver — three of them, actually — and when the P-3s were both established on long downwinds, the student came in and landed, full stop.

On another flight, I was on the last leg of a cross-country flight to satisfy the eligibility requirements for a student's instrument rating. We were just below the clouds at 3,000 feet. Darkness was gathering. A few minutes before, a southeast bound Aztec departing an airport in the previous approach control sector had reported light icing when climbing out of 3,400 feet. Very interesting information, considering that the freezing level had been forecast at 6,000 feet or higher. Now the voice on the radio spoke our call sign and commanded, "Climb and maintain four thousand." Bad idea — what made the altitude change seem even more puzzling was that we would soon be on the approach, a procedure that usually calls for a descent to 2,300 feet from our present position. There were no other airplanes flying the procedure that would have caused us to remain higher up. I held out my hand to signal delaying the climb and keyed my microphone to begin the negotiations. "How about a vector instead?" I said. "We heard some talk of ice a few miles back."

In a surprised, almost embarrassed tone, the controller immediately responded, "Bonanza Five Echo Victor, turn left heading 120, vectors around VFR traffic outbound from the airport that will be passing from left to right, 4 miles." It worked just fine. Unaware of icing potential in the area, the controller was performing a routine juggle to preserve aircraft separation, and he had decided upon a climb as the easiest method of getting us past the other aircraft. I thanked him for approving plan B, and a few moments later, we were descending to 2,300 feet to begin the approach.

An authoritative voice on the radio isn't always the reason pilots put themselves in a position they'd rather not be in. Sometimes just the silent presence of an authority figure on the scene upsets a pilot's priorities and threatens the security of the flight if a pilot's self- confidence is still lacking. As an instructor, I see this most often during the landing phase. The student, or pilot, makes a nice landing, but then a strange thing happens. Suddenly, for no apparent reason and regardless of aircraft speed and need for directional control on rollout, the pilot crams on the brakes in a screeching, shuddering effort to clear the runway at the next taxiway. The airplane suffers greatly during such an operation, and I am certain that many "loss of control on landing" incidents have their origins in such attempts, although I have been fortunate not to have witnessed such an outcome to date.

It is one thing to try to get down and off as quickly as possible when the tower controller keys his mike and commands, in rapid-fire ATC- speak, "Turn right next taxiway, contact ground 'point nine' when clear, no delay, traffic a DC-10 on a 3-mile final" — but even then, landing and rollout should be well planned, with a go-around in your pocket if all else fails. When traffic is light and there have been no special requests for an early exit, many pilots still put themselves and their aircraft at risk. The only reason I can think of is that they are reacting to the pressure they feel from knowing that "Big Brother is watching" or are simply afraid to admit that they are "unable" to perform a particular operation.

On the latter point, be honest with the controller about your limitations. He may not be a pilot at all, and some touchy situations have arisen from a controller's having overestimated a pilot's experience level. Honesty can clear things up in a hurry. This scenario was well illustrated by an exchange heard on our departure frequency last summer.

ATC: "Cessna Two Tango Mike, proceed through the area, remain west of the localizer at all times."

2TM: Roger, I don't know what a localizer is."

ATC: "Cessna Two Tango Mike, no problem, fly heading 180, or just fly down the river if you like."

ATC isn't the only Big Brother figure that can cause a new pilot to get himself in over his head. As noted above, flight instructors or fixed-base operators can be just as intimidating, as a 40-hour student discovered one recent day.

On the day in question, as I sat in the terminal, a young fellow approached and asked if there were any flight instructors around. From the charts and logbook in his hand, I surmised that he was a student out on a solo cross country, but I wondered about that because on such a day, with a cold front approaching from the west, the southerly winds gusting ever higher, and reports of low-level wind shear in abundance, there probably wouldn't be any students flying around by themselves.

When I identified myself as an instructor, down he sat in the next chair and out came a tale of anxiety and indecision that caused me to grit my teeth in anger. It seems that the fellow had been sent off that morning from an airport in northern Massachusetts on a solo cross country in a Piper Warrior. He had been tossed around unmercifully in the increasing turbulence and had nearly lost control when landing at our airport in the gusting crosswind. Now, with the winds increasing and darkness near at hand, he was in no mood to point the Warrior's nose into a strong headwind (40 knots at 3,000 feet) and repeat the performance on the way home.

The briefer at our local flight service station, himself a 15,000- hour military pilot, agreed with the student's assessment. But when the student telephoned the home base to announce his decision, he received a stern chewing out, was told he would have to pay the cost of sending another airplane after him, was scolded for getting a new weather briefing — if you can believe that — and was informed that "flight service always says not to go." In the background, he said, he could hear laughter, and people calling him a "wimp" as his instructor yelled at him over the telephone.

"Am I making too much of this weather?" he asked me in anguish. "I don't know what to do. I nearly lost it on final coming in here. But down there, they say it's not that bad."

I reassured him, as did another instructor who had joined the conversation, that his discomfort with the conditions was reason enough to stay on the ground. Neither I nor my colleague would have sent a student on a solo flight this day, we told him, and I put that opinion in writing, inviting him to present it to his FBO in the event it attempted to stick him with ferrying costs. We had a nice chat, and he impressed me as a careful, safety-conscious student who will make a fine pilot someday soon.

His dilemma reminded me of a day many years ago when I refused to fly a Skyhawk that had oil dripping from under the engine compartment. I remembered explaining my decision to the chief pilot, who listened impassively while two young hotshots stood in the background, pointing and giggling. The next day, someone flew the airplane, and the engine quit.

The saddest part of this student's cross-country story is that I feel pretty sure that if a couple of us flight instructors had not been lounging around the terminal this day, he would have ignored his own good instincts, gotten back into his airplane, and flown home, shaken and scared, in conditions forecast to be worse than those he had already encountered. It would have been he, of course — not the people baiting him over the telephone — who would have suffered the consequences if anything had gone wrong.

It's tough to challenge authority — tough, and lonely, too — but like everything else about flying, the only thing that makes it easier is practice, experience, and a keenly developed sense of priorities.

Dan Namowitz is a multiengine-rated commercial pilot and CFII living, flying, and instructing in Maine.

How It Works: Carb Talk

BY MARC E. COOK

Not much is taught in basic training about how an airplane works, at least in the mechanical sense. Sure, you get the basics of aerodynamics and you learn the need for plentiful, clean fuel, but many of an airplane's systems remain to be explained only through cursory discussions in the pilot's operating handbook.

During training, one of the last parts of the simple airplane's systems to be explained is the carburetor, which is unfortunate because it is quite different from any kind of carburetor you may be familiar with. Why do you need to adjust this thing called mixture? Why does the carburetor sometimes need heat?

First, however, let's think about the carburetor's basic function. Simply put, it is to deliver air and fuel to the engine in the correct proportion, about 15 parts of air for every part of fuel. This combination of fuel and air, called, not surprisingly, a mixture, is then pulled into the engine (a result of the piston moving down the cylinder while the intake valve is open), compressed, and fired off with the spark plug on the power or expansion stroke. If you add in the final expulsion of spent gasses during the exhaust stroke, you have just described the basic Otto- cycle engine — yes, your common Lycoming or Continental.

The carburetor itself is a fairly basic device. It consists of a tube, through which the air flows to the engine. This tube, called the throat, is constricted, venturi-fashion, which helps to locally accelerate the airflow through the carburetor. Such acceleration is needed to help the fuel mix well with the incoming air; this fuel is distributed by a small ring or tube located in the middle of the throat. Here is the elegant part of the carburetor: The fuel itself is carried into the air stream by siphon action, proportional to the amount of air being admitted into the engine.

Naturally, you need some means of controlling the airflow; this is accomplished with a throttle plate (also called a butterfly valve), located past the point where the fuel is admitted, very close to where the carburetor is mounted to the engine. (In Lycomings, intake-air tubes run through the bottom of the oil pan to each cylinder; Continentals use an exposed one-into-four spider to separate the fuel/air mixture for each cylinder.) The butterfly valve is connected directly to the throttle control in the cockpit.

Another control in the cockpit is labeled mixture. We don't need variable mixture controls on carbureted cars because they don't have to deal with the altitude extremes airplanes do, and the electronic fuel injection so common in today's cars takes care of such a task — should it even be needed — automatically. But the airplane must work in widely varying air densities, so a mixture control became necessary early on in engine development and remains so today.

The carburetor has a small holding tank of sorts: the float bowl. Gas from the fuel tanks and any external pumps (there are none in a Cessna 150 or 152) comes into the bowl, maintained at a preset level by a float and needle valve arrangement. As you might imagine, there is a port from the bowl to the discharge mechanism in the carburetor. It's a fairly simple matter, then, to restrict this port to control the ratio of fuel admitted to the amount of air flowing through the carb. This is accomplished with a tapered rod moving into and out of a fixed orifice. Move the mixture control to full rich, and the rod retreats completely from the hole, allowing the most fuel to flow. Select idle cutoff on the mixture control, and the rod completely fills the hole.

Now that you understand how the mixture is controlled, you might want to know how and why you must control it. A big part of understanding mixture management is to think like an engine — simply put, it wants a lot of fuel when it's making a lot of power. So it will also want less fuel — sometimes a lot less — when the throttle is pulled back, as it would during descent. Many instructors will teach to lean the mixture on the ground, during taxi; this is more common on certain types of trainers and in the warmer climates. You do this to keep excess fuel from leaving lead deposits on the spark plugs; a rough runup will usually disclose when one or more plugs has become fouled and therefore cannot fire as intended.

When operating out of high-elevation strips, there's an additional step. Lean for best power before attempting the takeoff. Sitting at the end of the runway, apply the brakes and full throttle and slowly lean the mixture until rpm peaks; use this setting for the takeoff unless unusually rough running or high engine temperatures occur, in which case you need to enrichen a bit.

Most POHs recommend leaving the mixture full rich until reaching 3,000 or 5,000 feet. Keep in mind that this refers to density altitude, so plug in those temperatures accordingly. You can and should lean in the climb, once you've reached the recommended altitude; as with the ground operations, slowly pull back the mixture until the rpm peaks. If you leave the mixture full rich during cruise, your carefully calculated fuel consumption figures will be greatly in error. Remember, the numbers in the POH reflect proper leaning.

And what about carb heat? Because the venturi restriction in the carburetor body both accelerates and cools the air, there is the chance for ice crystals to form on the throttle plate, downstream of the venturi. Left unchecked, the icing can completely close off the carb throat and cause engine stoppage. Applying carb heat simply directs air heated by proximity to the exhaust system (no exhaust gases themselves) to the carburetor. Depending on airplane type, you will often use carb heat as a preventative measure at low power settings and before landing to prevent the formation of carb ice. In some types, you will only pull on the carb- heat knob if you suspect icing, which would manifest itself as a rough engine or loss of power.

Practice Area: The Redline

BY WILLIAM K. KERSHNER

One spring morning as I was in my usual position atop a ladder washing one of the Aeronca Champion trainers, I noticed a new postwar retractable enter slowly on the downwind leg and carefully approach and land to the southwest on our grass runway.

It was spring of 1946, and with a total flight experience of 33 hours 20 minutes, I was always willing to stop washing airplanes and watch other pilots' landings with a professional and critical eye.

The airplane bounced twice. I could have done much better. In my later years, I've often wished that I knew as much about flying as I did those first few hours. Apparently as time passed on, all that knowledge gradually slipped my mind.

I recognized the airplane, a low-wing Bellanca Cruisair, unique in lightplanes in those days in that it had a fin on each end of the horizontal stabilizer, giving the appearance of a small Lockheed Constellation. The claim was also made that the airplane cruised at 150 miles per hour with a 150-horsepower (Franklin) engine. No other airplane could get a mile per hour per horsepower at that airspeed.

Before I could get down to the parking area to direct the pilot (again, always willing to forgo the pleasure of airplane washing), he had parked and shakily gotten out and stood leaning with one hand on the aft fuselage.

It was Mr. Dalton (not his real name, of course), all right. He had gotten a surplus Fleet biplane trainer in late 1945 and had flown it for a while, but apparently it wasn't fast enough, and he bought the Bellanca from our local dealer a couple of weeks before.

Dalton was the prime example of people who've flown airplanes for a long calendar time, and perhaps many hours, but who failed to absorb any new knowledge. ("Don't tell me about that — I have more than 10,000 hours." No, he has one hour, 10,000 times.) Apparently the long experience had let him down because he was quite pale.

I walked over and asked if I could help him.

He said that he had narrowly escaped being killed on his trip from Memphis to his home field, about 30 miles northeast of this airport.

The gist was that as he was flying at cruise and making extraordinarily good time, he decided to check his groundspeed (apparently having nothing better to do). To his horror, he found that the groundspeed was 10 mph over the airspeed indicator redline value of 175 mph. He had, of course, slowed the airplane by 30 mph — to be on the safe side — and landed at the nearest airport (ours) to check for possible damage.

The airspeed indicator is a pressure gauge, measuring the dynamic pressure of the air force on the airplane in pounds per square foot. This dynamic pressure is what puts stress on the airplane and is the product of the air density and the velocity (squared) of the molecules passing the airplane, so the airspeed indicator tells the pilot whether he is in trouble in this regard. For example, a satellite in orbit at 18,000 mph at 300 miles' altitude would have no measurable stress on it at that great speed because of the extremely low density of the "air" up there.

The same thing basically applies to groundspeed or the relative speed of the airplane over the ground. If an airplane at sea level on a standard day is indicating 150 mph (assuming the airspeed indicator is accurate) flying due east in a mass of air and that air mass itself is moving 50 mph due east, the airplane will be moving at 200 mph, though the pilot won't know this unless he checks his speed in relation to ground checkpoints.

I tried to explain to Dalton that the airspeed needle told him whether the airplane was in trouble or not. He became quite (more) agitated and stomped into the office, where he told the boss (I found out later) "You'd better do something about that smart-ass kid out there." Because the boss had given me ground school on that very subject, Dalton's diatribe met the same reaction as if he had been caught lobbing elephant droppings in the family swimming pool.

Dalton later stomped out of the office and went back to the airplane, mad as hell, and, without looking at any part of the airplane (preflight checks aren't necessary for old-timers), started it up to continue his adventurous flight homeward.

The airplane did not move to taxi, as I had meanwhile helpfully (honest) tied the tail and wings down and chocked the main wheels. Even full power wouldn't allow the airplane to move.

Based on his verbal expressions after he got out and was untying the airplane, I did not really believe that he was a fundamentalist minister as I had been told.

Three years later, we were to be together once more when I was a flight instructor and the same boss assigned me to fly with Dalton for a review after a layoff of a year. He had sold his Bellanca.

We started with high-work: turns, steep turns, slow flight, and stalls in the Champion. Things went relatively well (though on several occasions, the ball in the slip indicator was hard-put to stay in the cabin, much less in the instrument) until we began the wind correction maneuvers.

After we got back on the ground, he once more stomped into the office and stormed that "that snotty-nosed kid instructor" (among other descriptions) wouldn't let him hold rudder and opposite aileron to correct for a crosswind during the rectangular course practice.

"I've corrected for a crosswind that way since the early 30s." Fortunately for me, the boss had been my flight instructor all along, and I was teaching the way he had taught me (setting up a wind correction angle in coordinated flight with no rudder or ailerons being held once it was set up). Right there we lost a rental customer.

Now, after flying 47 years, when I get into a discussion with younger instructors and pilots, I catch myself about to use the point of "how many years I've done that maneuver" instead of a logical presentation, but I think of Dalton and drop that idea. (Well, not always.)

Dalton was in his late 40s 40 years ago. I sincerely hope he's still flying and that he wasn't killed in a skidding turn onto final somewhere.

William K. Kershner, AOPA 084901, is an aviation writer and flight instructor who has been flying for more than 48 years, has taught 433 students aerobatics, and received the 1992 National Instructor of the Year Award.