Pilot Performance - The Right Angle of Attack
by Henry K.

An understanding of the fundamentals is vital, as with flying and in business the ‘intuitively obvious’ and ‘knee jerk’ responses are often incorrect, especially when operating outside of the ‘envelope.’

For an aircraft in flight if you want to climb and gain altitude you pull back on the control column to raise the nose of the aircraft and add power. Conversely, to descend you reduce power and lower the nose to the desired rate of descent and airspeed. The coordinated use of the flight controls becomes automatic with training and generally holds true for most normal operating conditions encountered. The difficulties arise in the more extreme and unusual conditions where these reflex responses are not appropriate. And most unfortunately, these circumstances are the most demanding and perilous if not responded to correctly and decisively.

A few fundamentals:

The angle of attack!

The underlying fundamentals are in the physics of flight and the operating limitations or ‘envelope’ of the aircraft. Lift is achieved through the shape of the airfoil (wing) and the angle of the airfoil in relation to the relative airflow. The angle of the wing vs the relative airflow is ‘the angle of attack.’ Generally (and intuitively), an increase in the angle of attack will translate into greater lift and vice versa. However, increasing the angle of attack to more than approximately 17 degrees (slight variations between aircraft) will cause a separation of airflow from the wing’s upper surface and a loss of lift. A complete loss of lift (or stall) will occur over the threshold of the angle of attack regardless of airspeed, flight attitude or weight, and every aircraft has an angle of attack where maximum lift occurs immediately preceding the stall. The intuitively obvious response, taken beyond the threshold of the fundamental capabilities of the aircraft will be wrong.

A stall or loss of lift is undesirable to say the least. Complete loss of lift means loss of altitude in a rather dramatic fashion - imagine several thousand pounds of metal falling through the sky - the ultimate career limiting move. The untrained reflex response to a stall will also be wrong. A knee jerk reaction to a loss of lift is to pull back on the control column and to reduce power. This increases the angle of attack further and therefore aggravates the stall making the recovery much more difficult. The correct and learned response to a stall is to push the control column forward to lower the nose and add power. The control inputs are designed to decrease the angle of attack to the ‘operating envelope’ below 17 degrees to regain the airfoil’s capability to provide lift.

To complicate matters the knowledge of the fundamentals creates the awareness that it is not solely the angle of the airfoil or attitude of the aircraft that determines lift. It is the relative angle of attack vs the relative airflow that is critical. In more severe weather the angle of attack may change purely through the outside airflow through updrafts, downdrafts, microbursts, wind shear and wind gusts and an aircraft can be ‘stalled’ in almost any attitude or configuration. 

The trained response for stall recovery - nose down add power - is put to a severe test in a stall experienced in a descent. Imagine the conflict between reflex and knowledge - of being in a nose down attitude accelerating towards terra firma and being instructed to push the nose down farther and add power. The intuitive and untrained response to severe or unusual conditions which exist outside of the normal operating range will be wrong, and with very serious consequences.

More of what works within normal circumstances
will not work outside the ‘envelope!’

The knowledge of the fundamental principles and the capabilities of the craft are vital to ensure success. What is often intuitively obvious in normal operating circumstances may not (or likely will not) hold true beyond the operating envelope. More of the same response will therefore degrade performance. The knowledge of the fundamentals in terms of the angle of attack respecting the design features of the craft (airfoil) and the external conditions is vital to deal accurately and decisively with the more severe and challenging circumstances. As in business, more of the same response will seriously degrade performance in more severe ‘weather’.

The angle of attack, in terms of the external relative airflow and the design capabilities of the aircraft must be ‘right’ to execute maneuvers safely, and with precision. A knowledge of the fundamentals is vital for success.

It’s all about attitude and power ... and a knowledge of the fundamentals. 

Pilot Performance TM - Superior Performance and Adventure

"In life you’re either a passenger or pilot ... It’s your choice."

Henry K. is a private pilot, author, artist, actor, whale watcher, fly fisherman, tour guide, seasonal server and surfer residing in Tofino, B.C. Canada, as well as a contributing editor to The CEO Refresher.

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Copyright 1999 by Henry K. All rights reserved.

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