Windshear 15

Windshear Reporting

If you encounter a windshear on an approach or departure, you are urged to promptly report it to the controller. An advanced warning of this information can assist other pilots in avoiding or coping with a windshear on approach or departure. The recommended method for windshear reporting is to state the loss or gain of airspeed and the altitudes at which it was encountered. If you are unable to report windshear in specific terms, you are encouraged to make reports in terms of the effect upon your aircraft.

Visual Clues

You can see thunderstorms and hence receive a mental trigger to ‘think windshear’. Once alerted, look out for tell-tale signs such as:

•Divergent wind sleeves or smoke.

•Strong shafts of rain or hail, also ‘virga’ (intense precipitation which falls in shafts below a cumulonimbus cloud and evaporates in the dry air beneath).

•Divergent wind patterns indicated by grass, crops or trees being beaten down or lashed.

•Rising dust or sand.

To observe and recognize any of the above will suggest that windshear danger is very close, if not imminent; nevertheless, a few seconds of advance warning may make all the difference, if the warning is heeded and those seconds put to good use.

Conclusions

Most pilots will experience windshear in some form or other; for most it may be no more than a very firm landing or a swing on take-off or landing requiring momentary use of, perhaps, full rudder for correction; they will probably put it down to ‘gusts’. Some few pilots will experience more authentic examples of windshear which will stretch their skills to the limit. A very small number may find their skills inadequate. There is no sure way of knowing in advance the severity of windshear which will be encountered, so it is better not to put one’s skills to the test, rather than find them inadequate. Windshear, particularly when linked with thunderstorms, has caused disaster in the past and may well cause disaster again, but it will not harm those who understand its power and have the good sense to avoid it. An inadvertent encounter on the approach is most likely to destabilize it to such an extent that a missed approach is the only safe course, and the sooner that decision is made, the safer it is likely to be. Other encounters must be treated on their merits, but any hint of ‘energy loss’ should be met with a firm and positive response in line with the guidance put forward.

Recognize	-	that windshear is a hazard.
and
Recognize	-	the signs which may indicate its presence.
Avoid	-	windshear by delay or diversion.
Prepare	-	for the inadvertent encounter by a speed ‘margin’ if ‘energy loss’
		windshear is suspected.
Recover	-	know the techniques recommended for your aircraft and use them
		without hesitation if windshear is encountered.

Windshear 15

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15 Questions

Questions

		1.	Take-off EPR is being delivered by all engines and the take-off is proceeding
			normally, the undercarriage has just retracted. Which initial indications may be
			observed when a headwind shears to a downdraught?
			a.	Indicated Airspeed: constant. Vertical Speed: decreases. Pitch Attitude:
				decreases.
			b.	Indicated Airspeed: increases. Vertical Speed: decreases. Pitch Attitude:
				constant.
			c.	Indicated Airspeed: decreases. Vertical Speed: constant. Pitch Attitude:
				constant.
			d.	Indicated Airspeed: decreases. Vertical Speed: decreases. Pitch Attitude:
				decreases.
		2.	Maximum downdraughts in a microburst encounter may be as strong as:
			a.	6000 ft/min.
			b.	7000 ft/min.
			c.	8000 ft/min.
			d.	10 000 ft/min.
		3.	An aircraft that encounters a headwind of 45 knots, within a microburst, may
			expect a total shear across the microburst of:
			a.	80 kt.
	15		b.	40 kt.
			c.	90 kt.
	Questions		d.	45 kt.
		4.	What is the expected duration of an individual micro burst?
			a.	Two minutes with maximum winds lasting approximately 1 minute.
			b.	Seldom longer than 15 minutes from the time the burst strikes the ground
				until dissipation.
			c.	One microburst may continue for as long as 2 to 4 hours.
			d.	For as long as 1 hour.
		5.	Which windshear condition results in a loss of airspeed?
			a.	Decreasing headwind or tailwind.
			b.	Increasing headwind and decreasing tailwind.
			c.	Decreasing headwind and increasing tailwind.
			d.	Increasing headwind or tailwind.
		6.	Which performance characteristics should be recognized during take-off when
			encountering a tailwind shear that increases in intensity?
			a.	Loss of, or diminished climb ability.
			b.	Increased climb performance immediately after take-off.
			c.	Decreased take-off distance.
			d.	Improved ability to climb.

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			Questions		15
	7.	Which condition would INITIALLY cause the indicated airspeed and pitch to
		increase and the sink rate to decrease?
		a.	Tailwind which suddenly increases in velocity.
		b.	Sudden decrease in a headwind component.
		c.	Sudden increase in a headwind component.
		d.	Calm wind which suddenly shears to a tailwind.
	8.	Which INITIAL cockpit indications should a pilot be aware of when a constant
		tailwind shears to a calm wind?
		a.	Altitude increases; pitch and indicated airspeed decrease.
		b.	Altitude, pitch, and indicated airspeed increase.
		c.	Altitude, pitch, and indicated airspeed decrease.
		d.	Altitude decreases; pitch and indicated airspeed increase.
	9.	What is the recommended technique to counter the loss of airspeed and resultant
		lift from windshear?
		a.	Maintain, or increase, pitch attitude and accept the lower than normal
			airspeed indications.
		b.	Lower the pitch attitude and regain lost airspeed.
		c.	Avoid overstressing the aircraft, pitch to stick shaker, and apply maximum
			power.
		d.	Accelerate the aircraft to prevent a stall by sacrificing altitude.
	10.	Which of the following would be acceptable techniques to minimize the effects of a		15
		windshear encounter?
		1.	To prevent damage to the engines, avoid the use of maximum available		Questions
			thrust.
		2.	Increase the pitch angle until the stick shaker activates, then decrease back-
			pressure to maintain that angle of pitch.
		3.	Maintain a constant airspeed.
		4.	Use maximum power available as soon as possible.
		5.	Keep to noise abatement procedures.
		6.	Wait until the situation resolves itself before taking any action.
		a.	1, 3, 5 and 6.
		b.	2, 3 and 5.
		c.	2, 3, 4, 5 and 6.
		d.	2 and 4.

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15 Questions

11.Which of the following statements about windshear is true?

1.Windshear can subject your aircraft to sudden updraughts, downdraughts, or extreme horizontal wind components.

2.Windshear will cause abrupt displacement from the flight path and require substantial control action to counteract it.

3.Windshear only affects small single and twin engine aircraft. Large, modern, powerful, fast gas turbine engine powered aircraft will not suffer from the worst effects of a microburst.

4.Microbursts are associated with cumulonimbus clouds.

5.Windshear can strike suddenly and with devastating effect which has been beyond the recovery powers of experienced pilots flying modern and powerful aircraft.

		a.	1, 2, 3, 4 and 5.
		b.	1, 2 and 4.
		c.	1, 2, 4 and 5.
		d.	2, 3, 4 and 5.
12.		A microburst is one of the most dangerous sources of windshear associated with
		thunderstorms. They are:
		a.	small-scale intense updraughts, which suck warm moist air into the
			cumulonimbus cloud.
		b.	small-scale shafts of violent rain, which can cause severe problems to gas
			turbine engines.
		c.	large-scale, violent air, associated with air descending from the ‘anvil’ of a
15		d.	thunder cloud.
Questions			small-scale (typically less than 1 mile in diameter) intense downdraughts
			which, on reaching the surface, spread outward in all directions from the
			downdraught centre.
13.		Thrust is being managed to maintain desired indicated airspeed and the glide slope
		is being flown. Which of the following is the recommended procedure when you
		observe a 30 kt loss of airspeed and the descent rate increases from 750 ft/min to
		2000 ft/min?
		a.	Increase power to regain lost airspeed and pitch-up to regain the glide slope -
			continue the approach and continue to monitor your flight instruments.
		b.	Decrease the pitch attitude to regain airspeed and then fly-up to regain the
			glide slope.
		c.	Apply full power and execute a go-around; report windshear to ATC as soon
			as practicable.
		d.	Wait until the airspeed stabilizes and the rate of descent decreases, because
			microbursts are quite small and you will soon fly out of it.
14.		Which of the following statements are correct?
		1.	A rapid increase in headwind is an ‘energy gain’.
		2.	A rapid loss of tailwind is an ‘energy gain’.
		3.	A shear from a tailwind to calm is an ‘energy gain’.
		4.	A shear from calm to a headwind is an ‘energy gain’.
		5.	A shear from headwind to calm is an ‘energy loss’.
		a.	1, 2 and 4.
		b.	1, 2, 3, 4 and 5.
		c.	1, 4 and 5.
		d.	4 and 5 only.

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Questions

15.Which of the following statements are correct? 1. A downdraught is an ‘energy gain’.

2.A rapid loss of tailwind is an ‘energy loss’.

3.A shear from a tailwind to calm is an ‘energy loss’.

4.A shear from calm to a headwind is an ‘energy gain’.

5.A downdraught is an ‘energy loss’.

a.1, 3 and 4.

b.1, 2, 3 and 5.

c.1, 4 and 5.

d.4 and 5 only.

16.Which of the following sequences might be encountered when flying into a microburst?

a.Increased headwind, followed by downdraught, followed by increased tailwind on the approach, or following take-off.

b.Increased headwind, followed by downdraught, followed by increased tailwind on the approach. Increased tailwind, followed by downdraught, followed by increased headwind following take-off.

c.Increased headwind, followed by downdraught, followed by increased tailwind on take-off. Increased tailwind, followed by downdraught, followed by increased headwind on the approach.

d.Increased tailwind, followed by downdraught, followed by increased headwind on take-off. Increased headwind, followed by downdraught, followed by increased tailwind on the approach.

17.Which of the following statements is correct when considering windshear?

1.Recognize that windshear is a hazard to all sizes and types of aircraft.

2.Recognize the signs which may indicate its presence.

3.Avoid windshear by delaying departure or by diverting if airborne.

4.Prepare for the inadvertent encounter by a speed ‘margin’ if ‘energy loss’ windshear is suspected.

5.Know the techniques for recovery recommended for your aircraft and use them without any hesitation if windshear is encountered.

a.2, 4 and 5.

b.3, 4 and 5.

c.1, 2, and 5.

d.1, 2, 3, 4 and 5.

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