In the days before the arrival of the Boeing 757 and Airbus A 320, with their glass cockpits, full-feature autopilots and autothrottles, most airline pilots flew their aircraft by hand from takeoff until reaching the flight levels and then all the way back down again. Even though we’re talking big and complicated systems, they could do it with great precision. How? They knew their configuration settings down cold.
A few years back, a good friend and experienced former B-52 instructor returned to the cockpit after a four-year absence while he was busy flying a desk. During his first takeoff, flap retraction, and climb to FL 310, the airspeed was never more than plus or minus 5 knots, the altitude plus or minus 25 feet, and the heading right on the mark. The same for the descent, approach and landing.
Now, the “BUFF” is not the easiest aircraft to fly precisely due to its 1940s design features, quadricycle landing gear and huge fowler flaps. Watching this demonstration of aviation precision, the young copilot asked if this accuracy was due to the pilot’s “experience.” The pilot replied, “Maybe a little, but more likely because the night before I computed each pitch, power and trim change required to fly the airplane precisely.” You see, airplanes are not aware of the experience, or inexperience, of the pilot, but each aircraft is very aware of the laws of aerodynamics and physics.
So, which is primary, establishing the correct pitch, power settings and trim, or responding to the altimeter, airspeed and heading indications? Thanks to Mr. Jacob Bernoulli, Sir Isaac Newton, George Cayley and, of course, Mr. Charles Taylor, who gave practical aircraft propulsion its start, our aircraft follow a set of clearly defined rules. Their work created aircraft that comply with the laws of physics and are balanced in flight due to setting of precise pitch, power and configurations. The flight instruments are simply, to borrow a term from economics and business speak, a “lagging indicator” of where the aircraft is or has just been. Add in the additional time it takes the average busy pilot to see and process the indications on the panel while performing a multitude of other required tasks, and the term “chasing the gauges” becomes easier to understand.
So back to the B-52. As it turned out, there were only a couple power settings worth remembering. Takeoff and climb power are computed from the flight manual. Then, amazingly, a single total fuel flow value of a bit less than 20,000 pounds of total fuel flow per hour allowed the aircraft to either cruise at altitude in a clean configuration, fly downwind in the pattern with the flaps in the down position, or fly a 3-degree ILS final approach with both the flaps down and the landing gear extended.
And each configuration change required a specific trim change value. The landing gear was worth one trim unit, the flaps three-and-a-half units, and the airbrakes another unit or so. So as the aircraft was changing configuration, this pilot simultaneously set the appropriate power and trim settings. Remember back to the student pilot days, when the flight instructor covered up the airspeed indication to allow a pilot to land without it. The usual, counterintuitive result was that airspeed control immediately improved.
In our modest general aviation contraptions, power is usually set by RPM (for fixed-pitch prop power systems) or manifold pressure (when there’s a constant-speed prop). The settings are usually given for takeoff/climb power, cruise and traffic pattern/descent/ approach setting. The flaps and retractable landing gear each have their own specific trim requirement, on some airplanes more than on others.
So why wait to see what develops? As the aircraft slows and configures, we can simultaneously set the appropriate pitch power and trim setting. Many of our aircraft require a modest power increase and trim change as the last 10 degrees of flaps are employed. Anticipating this change (adding power while decelerating) with an appropriate power increase and trim response allows the aircraft to stop its deceleration and find the “sweet spot” on the ILS or visual final. Once the pitch, power and trim are set, check the instruments, and they will likely show on course, on glide slope and on speed. For VFR flying, this means more time to get your head (and your eyes!) out of the cockpit! For IFR, it means fewer distractions and more time spent navigating and communicating.
We human pilots have our work cut out for us. Autopilots don’t have to scan for traffic, talk on the radio, answer questions from the passengers (“are we there yet?”) or decide if the weather is okay for landing. Those of us flying single pilot, IFR, in a legacy aircraft need to do all that and more. We’ve got our work cut out for us.
So, what to do? Help your airplane fly the way it wants to. Think about the most-often-used pitch/power/configuration combinations and simplify the task at hand. Anticipate the required settings for each situation or configuration and be confident that when you check the gauges, the cockpit indications will be what you expect.
Concentrate on fewer and more precise throttle and control inputs rather than many more reactive ones. If the gauges and the windscreen picture do not agree, rethink your inputs. Remember, each time we make a control input, our aircraft will check in with the usual suspects (Bernoulli, good old Sir Isaac, Cayley and Mr. Taylor) to make sure it follows all the rules. You can make your flying more efficient and precise by making your plane’s job easier. PP
Frank Ayers has been flying for over 45 years. He is an experienced military instructor pilot with over 4,000 hours in the Boeing B-52 and holds both ATP/B757/767 and CFI certificates with over 2,300 additional hours in a wide variety of general aviation aircraft. He enjoys teaching young people about the art and sci- ence of aviation and flight safety at Embry-Riddle Aeronautical University.