Flying by the Numbers (C-172)

P + P = PP

(Pitch + Power = Predictable Performance)

C-172

This concept is sometimes called Flying by the Numbers. It is described in Exercise 6 of the Flight Training Manual (FTM). The numbers for the club’s C-172 are described below under Flight Attitudes and Numbers.

For each phase of flight there is an Attitude and a Power Setting, followed by an airspeed and a vertical speed. You should have them memorized.

Flight Attitudes and Numbers (memorized)

CLIMB

  • Attitude:               Climb (cowl touching horizon)

  • Power:                  Full

  • Airspeed :             91 MPH

  • Rate of Climb:     700-800 fpm

CRUISE

  • Attitude:                 Cruise (cowl 4 inches below horizon)

  • Power :                   24-2500 RPM

  • Airspeed:                110-120 MPH

  • Altitude:         Hold with small attitude changes (Don’t touch throttle!)

APPROACH

  • Attitude: Approach (cowl 4-6 inches below horizon, depending on flap)

  • Power:         1500-1700 RPM

  • Airspeed:    75-80 MPH (maintain with slight changes of attitude)

  • Rate of descent:      400-500 fpm

  • Approach slope:     adjust with slight changes of power

CRUISE DESCENT

  • Attitude:             Descent (cowl 5 inches below horizon)

  • Power:                Reduce to avoid exceeding 2500 RPM

  • Airspeed:            Green Band

  • Rate of descent:  500 fpm (Hold with small attitude changes)

Drills (memorized)

Go-Around

  • Eyes Outside and ahead

  • Power Full Throttle

  • Attitude Climb

  • Carb Heat Off (use right thumb)

  • When positive rate of climb established,

  • Flaps Retract

Touch and Go

  • Eyes Outside and ahead. Track runway centre-line.

  • Aircraft weight on main wheels Retract Flaps (Find flaps handle by feel and flip up)

  • Power Full Throttle

  • Carb Heat Off (use right thumb)

  • At flying speed: Rotate smoothly to climb attitude

Baulked Landing

Note: A baulked landing is a go-around from the flare. It is a tricky maneuver in any airplane – you are close to the stall and close to the ground. Keeping your eyes outside and ahead is more important than ever.

In a C-172 with flap 40 a baulked landing requires considerable flying skill. The following is verbatim from the POH:

  • Throttle FULL

  • Carb Heat COLD

  • Flap 20°

  • Airspeed 65 mph

  • Flaps RETRACT (Slowly)

Note from the POH (section 2-19)

In a baulked landing (go-around) climb, reduce the wing flap setting to 20° immediately after full power is applied. If the flaps were extended to 40°, he reduction to 20° may be approximated by holding the flap switch to retract for 2 seconds and then returning it to neutral.

C172BaulkedLanding

This section of the POH is worth reading carefully and rehearsing in your head, and then practicing a few times under supervision. You will find that if you have to look inside to find the flap switch, your attitude will fluctuate dangerously.

Recommendations:

  • Keep your eyes outside and ahead and practice finding all controls by feel

  • Consider the selection of Flap 40° as a commitment to land

 

Notes on Transitions

These are exercises to help you develop good flying technique by learning to transition quickly and efficiently from one phase of flight to another.

Notice that in each case attitude is held while the aircraft accelerates or decelerates. (In two cases – Climb to Cruise and Cruise to Approach – altitude is held as well.) In all cases trim is last on the list. This means you will be holding considerable pressure on the yoke during the exercise. The purpose is not to develop your arm muscles. It is to learn how trim changes with airspeed/angle of attack, and learn to not to fly the airplane with the trim wheel.

As you get more practice you can anticipate the trim change needed, and trim during the speed change (example Cruise to Approach, two moderate up-trim movements of the wheel). However, you must still hold the required attitude with the yoke until the transition is complete and the aircraft is once more in trim. And you can’t let go then, either.

Other important take-aways are:

  • Attitude is primary. It tells you where the airspeed will be in ten to thirty seconds.

  • Power is constant during climb and cruise.

  • Notice that in Climb to Cruise and Cruise to Approach you are holding altitude. This will require very small changes to pitch attitude while holding a lot of pressure on the yoke. Not easy, but a great piloting exercise!

    Transitions

Climb to Cruise

  • Eyes:          Outside and ahead

  • Attitude:     Move to cruise attitude and hold (airplane accelerates) Keep lowering nose as necessary to hold altitude.

  • Power:       When airspeed reaches 115, reduce by ear (1 musical tone)

  • Trim:          Roll wheel forward to relieve pressure on yoke

Cruise to Approach

  • Eyes:               Outside and ahead

  • Attitude:         Hold cruise attitude

  • Carb Heat:     Hot

  • Power:           Reduce by ear to 1500-1700 RPM (airplane decelerates)

  • Attitude:        Raise nose as necessary to hold altitude. When airspeed reaches 80 MPH, lower nose slightly

  • Trim:             Roll wheel backward to relieve pressure on yoke

  • Airspeed:      Maintain with slight changes of attitude

Cruise to Climb

  • Eyes:       Outside and ahead

  • Power:     Full Throttle

  • Right Rudder :   Watch a point on the horizon. Apply rudder as needed to avoid left yaw

  • Attitude:    Climb attitude and hold (airplane decelerates)

  • Trim          Trim as necessary to relieve pressure on yoke

Cruise to Descent

  • Eyes:        Outside and ahead

  • Attitude:   Nose down to slightly below cruise attitude

  • Power:      Reduce as necessary to avoid exceeding 2500 RPM

  • Rate of descent:     500 fpm (Hold with small attitude changes)

  • Trim:         Optional. (For small altitude changes holding forward pressure will remind you to level off)

  • Airspeed:    In green band

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