Aviation

Flight lesson – Slow flight and stalls

I haven’t flown in a while so here’s another video from my “Learning to Fly” journey. I finally managed to successfully record output from the COMM radio, so you can hear exactly what is going on. I didn’t include a Pre-flight/Take off and steep turns practise, since that was covered in my previous series. In this video I’m performing 3 manoeuvres: Slow flight, Power-On Stall and Power-Off Stall.

screenie

HASEL check

Before performing any of these manoeuvres a short vital-actions check-list: “HASEL check” must be conducted. HASEL is an acronym for Height, Area, Security, Engine, and Lookout. Failure to perform the HASEL check is a serious safety violation and will constitute a failure on the flight test.

Height: Is there an enough altitude to recover from a stall if you enter one (In Markham practise area it’s about 3,500ft ASL).
Area: Make sure there is no city or airport nearby. Also check for antennas or any elevated obstacles.
Security: All seat belts are securely fastened and there are no loose articles.
Engine: Make sure that the engine instruments are reading that the engine is operating normally.
Lookout: Check for traffic and make sure there are no aircraft nearby.

After completing the HASEL check, a 90 Degree turn to either the right or left must be made, followed by another 90 Degree turn, this time in the opposite direction, checking for any aircraft around you.

Slow Flight

During a Slow flight the aim is to grasp the ability to recognize intentional and/or inadvertent entry into the slow-flight speed range maintain flight control within this range, and accomplish prompt recovery to flight in the normal speed range.

To enter Slow flight, power should be gradually decreased until Flight for Endurance level is reached. Then, slightly raise the nose and continue slowing down and correcting any drop in altitude. Next is to add flaps in stages (10, 20, 30) which will cause altitude to drop, so adding a bit of power is necessary to keep the Vertical Speed Indicator neutral. At this point a Stall warning horn will start to sound (As you can see in the video, the stall horn is broken in this plane). To recover from Slow Flight, first step is to add full power and as you begin to accelerate, raise the flaps back up to 0. Reach the initial altitude and set power back to normal cruise setting (2200 RPM on C172R).

Stalls

Stalll

Stall in fixed-wing airplane are often experienced as a sudden reduction in lift as the pilot increases the wing’s angle of attack and exceeds its critical angle of attack, thus when an airplane stalls, it has nothing to do with the engine. Stalls do not derive from airspeed and can occur at any speed – but only if the wings have too high an angle of attack.  A primary objective of stall training is to enhance safety by helping assure inadvertent stall avoidance or prompt stall recovery. It is critical to identify the stall and perform a quick recovery to avoid losing altitude during flight.

stall

Here’s a great video demonstrating stalled wing’s airflow:

Conditions that may cause Power-on stalls:
– Takeoffs and departure climbs, esp. short fields with obstacles
– Go-arounds
– En-route best-angle climbs

Conditions that may cause Power-off stalls:
– Approach and landing
– Turning base to final (may be crossed-control)
– After engine failure
– During glides; attempting to “stretch” a glide

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