Porpoising aircraft is not bouncing. Instead, it occurs if a pilot fails to control the plane after the first bounce. I explained in this post how a pilot could prevent a porpoising aircraft and why it happens.
Being unable to prevent a porpoise from landing can lead to a disaster.
Thus, it would be best if you learned everything about porpoising aircraft on the landing:
- What is a porpoising plane?
- What causes an airplane to porpoise?;
- What to do if you enter a porpoising landing?;
- Best practice to prevent aircraft porpoising;
- Dangers of porpoising on landing.
Imagine you are a private pilot on a cross-country flight. You are about to flare, and a sudden gust of air pushes your aircraft to a continuous oscillation of bounces over the runway. What will you do?
What is a porpoising aircraft?
Imagine an aircraft bouncing off the ground, and you push hard to land the airplane, which may cause repeated bounce of the plane. The plane’s repeating bounce will cycle over the runway until the pilot nose dive and crash land the airplane.
This continuous oscillation resembles a porpoise jumping on the water’s surface.
Porpoising aircraft is a situation that follows if the pilot fails to control an airplane bounce correctly.
Hence it is crucial to know the reason behind a porpoise on landing.
What causes an airplane to porpoise?
To understand a porpoise on landing, we must first understand what causes an airplane to bounce on landing.
Typically newbie pilots bounce in landing. The reason inexperienced pilots bounce on landing is that:
- Either they sink too fast over the runway;
- Or the approach speed of the plane was higher than recommended;
- Not rimming the airplane properly;
- Another reason for a bounce can also be the aircraft’s weight.
As I mentioned, a bounced landing is likely to make aircraft porpoise.
Assuming you, as a pilot, approached the runway with a higher airspeed than recommended. When you flare with a high airspeed, the aircraft will likely float.
When the aircraft floats, the plane loses airspeed quickly and sinks faster, resulting in a bounce.
Naturally, after a bounce, the pilot’s instinct is to push the aircraft yoke for a touchdown.
In this situation, pushing the airplane yoke too hard is a mistake.
If the airplane touches the ground with the nose landing gear first and then the main landing gear later at a high airspeed, the inertia at the aircraft’s rear will make the structure bounce off the ground again.
I believe the main reason for a porpoising aircraft is high approach airspeed.
The repeating bounces will ultimately go out of the pilot’s control and crash-land the aircraft.
In another instance, while you were about to touchdown, you first touched the ground with the nose landing gear.
This situation can also lead to a porpoise from the first bounce. Once the nose landing gear touches the ground first, the inertia on the aircraft’s tail pushes the plane off the ground and gains altitude. Gaining a very high altitude at this stage also can be the beginning of a porpoising landing.
What to do if you enter a porpoising landing?
Going around is the best thing to do when you enter a porpoising landing. It’s as simple as that.
An aircraft porpoises after a bounce. Once a pilot thinks he can’t control the aircraft anymore after the second bounce, it is best to go around.
After the first bounce, if the airspeed is too slow, the aircraft will touch the ground, but the touchdown impact will be immense.
If the aircraft did not stop the second time, instead it gained more altitude after the second bounce, the only thing you should do is go around. Pilots unaware of the porpoising situation might try to force the aircraft.
If you have gained altitude after the second bounce, immediately add full power and go around.
On the second approach, ensure your approach airspeed is correct and your sink rate is between 500 to 600 feet per minute on the final.
Trying to stop a porpoise on landing will make the situation worse. It is better to save yourself and the aircraft and attempt a dock again.
Best practice to prevent aircraft porpoising.
To prevent an airplane from porpoising, you have to master controlling the airplane’s speed.
Practice slow flights and maintain airspeed.
Also, learn to trim your aircraft early in your flight training. Many student pilots avoid cutting planes.
Finally, practice practice and practice landing touch and go.
No pilot can claim that they never had a bounced landing. It’s common for all pilots.
However, a porpoising aircraft is a situation that follows uncontrolled bounces.
An untrained pilot will fail to control a bounce correctly and enter a porpoise.
To prevent porpoises on landing, a pilot must maintain airspeed from the beginning of the landing phase.
VFR pilots have rules to follow and airspeed to maintain when they enter downwind. The airspeed is variable for different aircraft, but the technique is always the same.
The pilot must maintain airspeed on all legs of the approach.
Failure to maintain recommended speed on the final can be critical.
Typically the approach speed on the final is 1.3x VSO of the aircraft you are flying.
Maintain this airspeed with a descending rate of 500/600 feet per minute.
Once you are over the runway, you can break the glide and allow the airplane to sink slowly.
Another problem among student pilots is to flare too early. Remember to pull the yoke gently and not abruptly.
Pilots tend to pull the yoke abruptly if they do not trim the aircraft properly.
The reason for aircraft floating is abrupt back pressure on the yoke resulting in lift and aircraft gain altitude.
Another reason an airplane can float is the ground effect or a sudden gust of air that generates lift over the wings.
Therefore even if you perform flawlessly, the ground effect can result in the airplane bouncing.
The best practice to recover from floating is adding a little power and not allowing the airplane to sink fast. Even at 10 feet, a high sink rate will cause a harsh impact.
Your aircraft’s landing gears will bounce with that hard impact on the ground.
Prevention of a porpoising aircraft begins from the downwind leg and how you react after your plane’s first bounce.
If you think the aircraft is going for a second bounce, don’t allow it to have a nosedive. Instead, go around for a second attempt at landing.
Dangers of porpoising on landing.
Porpoising on landing and failure to recover will induce the airplane to nose dive. A nosedive at high airspeed indicates a severe impact on the ground, breaking the landing gears and propeller leaving the pilots and passengers injured.
As a pilot, don’t wait until you enter a porpoise landing, or never try too hard to bring the airplane to the ground. If the situation comes to that, the only thing you can do is to go around.