THE ONE BOUNCE RULE

Acknowledgements: Thomas P. Turner (Mastery Flight Training Inc.)

The pilot of a Mooney M20J “bounced multiple times during landing, then experienced landing gear collapse,” according to an FAA preliminary accident report this week.
The pilot, alone in the airplane, was not hurt. The extent of damage to the airplane is not yet reported; however, high performance retractable-gear airplanes rarely fare well following a gear collapse.

Pilot-induced oscillation (PIO) occurs when the airplane begins a departure from the desired flight path, and the pilot applies inappropriate, excessive or mis-timed corrections that result in ever-increasing excursions which threaten to force the airplane out of control. In short, the pilot is “behind the airplane” and his/her attempts at regaining control only make matters worse.

PIO can occur in any phase of flight, but it is usually associated with pitch excursions on landing and can rapidly develop to catastrophic proportions, even in the hands of an experienced test pilot. Airline pilots can enter a PIO; even test pilots flying the first glide tests of the Space Shuttle bounced and entered a PIO (at least I doubt that it was a pre-programmed flight test manoeuvre!).

Stresses can rapidly damage landing gear and other airplane structures. It can force the airplane off the runway, or out of control in roll or in a stall. Propeller strikes are common in propeller-driven aircraft.

Bounce a landing and PIO becomes a real possibility. Once a PIO begins your best option is to power up and go around (well, not in the Space Shuttle!). So:
  •        Add go-arounds after the main gear touches the ground to your recurrent training regimen.
  •        Be well-practiced in establishing the right pitch and angle of attack, while firmly  holding the proper attitude to prevent PIO.

There are two kinds of go-around, but some instructors only teach one. It’s comparatively easy to power up, pitch up and clean up from a point a couple of hundred feet above the runway lights. It’s quite another task to go around once the mains have touched, the speed is low, and the angle of attack is very near a stall.

My first instructors presented touch-and-goes as pseudo go-arounds; it wasn’t considered a touch-and-go if the nose-wheel of the Cessna touched the ground. We were learning the skill of aerodynamic braking, because some of us would go on to fly Air Force fighters.

But we were also learning the art of the on-runway go-around, with a lift-off in a condition that necessitated a firm push forward on the controls with power application, then finesse as flaps were retracted and flying speed restored. In short, we learned how to recover from PIO.

After my Air Force experience, and after seeing what my early students did after a bounced landing, even on a very long runway, I developed what I call The One Bounce Rule. Basically, The One Bounce Rule is this:
  •          If you bounce a landing, make a snap decision
  •         Immediately decide whether you have the speed (no less than five knots below your final approach “VREF” speed) and angle to attack to recover into a second flare
  •          Immediately decide whether there is sufficient runway remaining to come to a stop from the point you’ll touch down a second time, given the airplane and environmental conditions that exist at the time
  •       If the answer to either is “NO” or you have any doubt, go around immediately. PUSH and HOLD to acquire the proper airspeed, angle of attack and coordinated wings-level heading
  •          If the answer to both is “YES” and you elect to do so, PUSH and HOLD into a second flare
  •         If you bounce a second time, go around immediately. No hesitation, no questions asked. PUSH and HOLD to acquire the proper airspeed, angle of attack and coordinated wings-level heading

If a propeller strikes the surface it’s another story. Prop strikes can cause immediate, catastrophic engine damage or propeller damage that makes a go-around incredibly risky. They can also cause internal over-stresses that will become a catastrophic failure at some point in the future, usually without warning.

Most engine manufacturers recommend engine tear-down inspections after a propeller strike. One manufacturer considers a tear-down mandatory if the propeller speed is seen to drop any amount at all when the strike occurs, and even if a prop strike occurs when the propeller isn’t turning (for example, a towing accident).  If the damage is substantial enough the propeller must be removed from the airplane for repairs.

Attitude is everything, at least where PIO recovery is concerned. Practice so that you are proficient at hitting the proper attitude required to fly out of a bounced landing into a second flare if it’s advisable, or to initiate a go around as you add power and gradually clean up the airframe (retract flaps and landing gear consistent with type-specific considerations).

if you’ve bounced a second time, or if there is any doubt about being able to re-flare and land on the remaining runway after the first bounce, FOLLOW THE ONE BOUNCE RULE!


FLY SAFE!
Tony BirthComment