Colgan Air Flight Accident

2.22

Stalls

a stall is a loss of lift and increase in drug that occur when an aircraft is flown at an angle of attack greater than the angle of maximum lift

relative flow: direction of the airflow with respect to an aerofoil in flight

an aircraft may be stalled in practically any attitude and any airspeed.

Q1: Regardless the speed and attitude, an aircraft always stalls when the wings reach the same angle of attack. (critical angle of attack is certain value for each aircraft)

Q2: symptoms of an approaching tall

 airspeed

1. a decrease in the effectiveness of the controls, especially elevator and aileron control.
2. audible or visual stall warning devices fitted in most aircraft are activated prior to the stall
3. buffeting(the beating effect of turbulent airflow on the aircraft’s structure, which can be heard and/or felt) varies in intensity with different types of aircraft
4. loss of height, despite rearward movement of the elevator control

Notes for class

Colgan air flight  accident.

angle of attack negative relationship with airspeed

symptoms

1. decreased effectiveness of control
2. stall waning horn(5 to 10 knots before stall)
3. wing will buffeting
4. loss of height
5. wing drop or nose drop.
6. pulling back on control stick

Recover procedure

1. lower the nose
2. full power (control yaw, press right side pedals)
3. flaps up in stages (attitude) it relates to the lift and drag.
4. when airspeed in safe, pitching nose up to climb

Enter stalls procedure power off

1. power to idle
2. pitch to maintain the level flight
3. hear warning horn (first indication of stall)

Question

slow flight procedure

hazard check

airspeed for stall during turn

departure stall  different power stall

acceleration stall, air speed

2.23

Slow flight

HASELL check

Height; recover more than 2000feet

Airframe: Flaps cruise

Security: baggage net, seat belt

engine: gauges, mixture full rich, fuel pump on

Location: not in town, not in city

Look out: trim both left and right 90 degrees.

procedure of recover from slow flight

1. increase full power, control yaw
2. nose down
3. flaps up in stages (slowly change)
4. reduce power as airspeed to normal range

stalls

acceleration stalls: the aircraft will stall at higher airspeed when it sudden turns, pull-ups or abrupt changes in its flight path.

stalls during the turns

level or descending turn: the inside wing normally stalls first, and the aircraft will roll to the inside of turn

level turn: the inside wing is travelling more slowly than the outside wing and obtains less lift, causing it to sink and increase its angle of attack.

descending turns: downward spiral, the inside wing is meeting the relative airflow at a steeper angle of attack and is the one to stall first and drop lower

climbing turn: the higher wing will normally stall first and drop abruptly when the stalled condition occurs( it has higher angle of attack, so it will close to the critical angle of attack, tend to stall easily)

To avoid conditions that may lead to a stall or near stall, pay particular attention to the following

1. Apply full power, this  is a form of take-off under adverse conditions so nothing less than full power is adequate

2. Application of power plus the nose up trim used during the approach will tend to force the aircraft into a nose-hog attitude. anticipate this and compensate by holding the correct pitch attitude until the trim can be readjusted