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The Base to Final Turn

One of the most important and critical turns in the circuit pattern, and in your flight, is when you are ‘low and slow.’  The base to final turn is a critical manoeuvre that when done uncoordinated, can lead to an increased risk of an unrecoverable stall-spin accident. Because we are so low in that phase of flight, recovering from a stall-spin from that altitude is not possible.

When we overshoot this turn is where the problem can become critical. In an attempt to get the airplane back on the proper approach path to make the runway, many pilots add lots of aileron and find this doesn’t get them back on track enough. So, they add rudder in the same direction and though this turns the nose to where the pilot wants to go it also puts them in an uncoordinated flight profile.  Watch what happens here:

Overshooting often the cause

After overshooting the base to final turn, forcing the plane into a normal approach can become tragic.  The airplane can stall without having enough altitude to recover: once the stall spin develops, there is not much that can be done to bring it back.  A lot of the time why this happens is because the pilot turns base, not anticipating a tailwind, and before they know it, the tailwind has blown the plane through base.  So in order to get back on track the pilot will attempt to force the plane back on track using lots of aileron and rudder.

Other times the turn will be too timid, some people only turn 10-15 degrees in the pattern, which often does not get enough to get the plane where it needs to go.  Then people will push to past 30 degrees, but if this is coordinated, there is no need to bank the plane that far.

The problem comes when we use some aileron to get back on track but that doesn’t work, so we use more rudder to tighten the turn. This results in us being uncoordinated.  This increases the bank angle and rate of descent.   Many will use opposite aileron to soften the bank angle and pull back on the yoke to check the rate of descent.

This will increase the angle of attack on the inside wing – a stall and spin on the inside wing can come quickly.

How to avoid

If you notice that you are being blown closer to the runway on the downwind, anticipate that this wind will blow you through your base turn. So, turn early, watch your angle of bank and keep coordinated. If you cannot regain your track in a coordinated fashion, simply overshoot.  There is no shame in a go-around.

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Illustrative example of wing stall using yarn

This video shows what happens to the air flow over a wing as it stalls.  Yarn, placed all over this airplane wing is pushed backward by laminar airflow during regular flight.  When approaching stall speeds,  the laminar layer moves forward more and more until it is all the way at the leading edge of the wing and drops off, causing the wing to stall. The yarn shows the turbulent air moving forward very clearly.

Note where the turbulence starts as the wing starts to stall, and how it reorganizes as the wing recovers from the stall.

This video was made by Harv’s Air in Stenbach, Manitoba, where the pilot taped four rows of 4.5 inch long pieces of yarn over the entire wing of a Diamond DA40. The flight was over Southern Manitoba.

This video does a good job of illustrating what happens to the airflow as it goes over the wing during stall. Read more about stalls and angle of attack here.

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The perfect landing

Normal landing touchdown attitude

The perfect landing technique explained

The most difficult part of learning to fly is, I think, the landing.  It is a precise series of steps that, when individually understood both aerodynamically and intellectually, result in a straight, soft landing no matter the wind conditions.  Since going solo for the first time I have been doing solo circuits, and have really been concentrating on my landing. Unbeknown to me, my landings, though soft are actually not that great.  Once I feel the aircraft sink I have a tendency to let go of the aircraft and let it sink, instead of holding off elevator pressure as long as I can.  This is one of the things that I have really noticed since I began flying solo.

Proper landing procedure

The proper landing procedure always follows a good approach. In the Cessna 172, this is approaching at 70 knots (with zero flaps) or 60 knots (with full flaps).  We can also use different degrees of flaps, such as 10, 20 or 30 depending on the 172 model.  Once we are over the runway threshold, and 2 -3 feet above the ground, we flare – using whatever works for you for knowing when to flare!  – I use the rule of when “the ground starts to come up so fast that something must be done about it.”

Once that is accomplished, you will feel the sink. My issue has been, that once I feel the sink I ‘give up’ and assume the aircraft is ready to land, and let it sink. This can result in a hard landing.  For me, I don’t get the hard landings but  tend to let my nose wheel touch down too soon. This can be dangerous as it can result in wheelbarrowing. The key is to hold the landing attitude as long as possible and bleed off your airspeed slowly.  So once you feel the sink, pull up until you have a very nose high attitude or high angle of attack.  This will cause the aircraft to sink slowly and incrementally. It will allow the main wheels to touch down first, and the landing will be soft.

What are your landings like? Comment below