1.waketurbulence

1．WAKE TURBULENCE

Wake Turbulence 尾流

These questions are check if pilot familiar with the wake turbulence

avoidance

1. What does the top picture show?

The picture shows that there are 2 parallel runways in the airport机场里有两条平行跑道 and the distance between the 2 runways is less than

760m 两条跑道间的距离小于760米. An aircraft is taking off from one

runway. 一架飞机正从跑道上起飞 Nearly after the rotation point, 在抬轮点之后vortices are generated from it‟s wingtips.从飞机翼尖处产生

涡流 The left vortex rotates clockwise左侧涡流顺时针旋转 and the

right vortex rotates counter-clockwise右侧涡流逆时针旋转.I think the

aircraft is a heavy aircraft because it has 4 engines. 飞机有四发所以我认为是重型机The wake turbulence must be very strong 尾流肯定很强and may affect operations of following aircrafts on the other parallel

RWY.有可能影响到另一条平行跑道上后面飞机的运行 It‟s the

tower‟s responsibility to ensure enough separation between each aircrafts.塔台有责任确保每架飞机间的充分间隔

2. When does the wake turbulence pose the most danger to small

aircraft?

尾流何时对小飞机产生最大的危害

When the temperature is high and wind is calm, 气温高静风时the wake

turbulence will take much more time to dissipate尾流要很长时间才能消散. The wake turbulence‟s effect to small aircraft will be stronger in hot

weather.在热天里尾流对小飞机的影响更强 During the landing and

takeoff phases of flight, 在起飞和着陆阶段wake turbulence can be

especially hazardous.尾流尤其危险 Because during these stages,因为在这些阶段 small aircrafts are close to the ground . 小飞机离地面很近It

will make a recovery from the turbulence more difficult.从尾流中改出更加困难

3. Do large aircraft produce more wake turbulence than small aircraft?

Why?

大飞机比小飞机产生尾流大么？

Yes. Generally speaking, 通常来说， larger aircraft has more powerful

engine大飞机发动机功率大 and can produce more thrust and lift during

operation运行时产生推力升力较大, naturally the wake turbulence will

be stronger.自然尾流更强 Moreover, large airplane has wider wingspan,

so it will affect larger wider area. 此外有了更宽的翼展,大飞机的涡流会影响更广的范围That‟s why they produce more turbulence.因此他们产生更多的尾流。

4. In what circumstance do you need to avoid wake turbulence? What do

you do?

在什么情况下你需要避免尾流？应该怎么做？

When I fly beneath and follow the flight path of a large or heavy aircraft，I need to avoid wake turbulence. 当我在大型机或重型机航迹下后方飞行时，应该避免尾流I should keep communication with ATC and ensure

time or distance separation with preceding/previous traffic. 应与ATC保持联系并确保与前机的时间或距离间隔

5. What are the criteria for the “heavy” call sign designation, except for

the B757?除了B757机型，呼号后加heavy的标准是什么？

According to ICAO documents依据ICAO文件: Aircraft are divided into

the 3 categories by their Maximum Takeoff Weight (MTOW):飞机根据最大起飞重量分为3类 Aircraft with MTOW 136,000 kg or above

belongs to heavy aircraft, MTOW在136,000公斤以上的属于重型机

Such kind of aircraft must add „heavy‟ after their callsigns此类飞机在呼号后必须加上heavy比如… – for example A340, B777, and MD–11.

This can caution ATC and following aircraft to keep separation.这样可以提醒ATC及后面的飞机保持间隔。

These following questions are to see if the pilots can explain how to

avoid wake turbulence

1. You are in an A320, on an ILS approach 15 miles out, wind calm,

established glide path and localizer, following a B757. What is the

safe/minimum distance between you and the B757? Why?

B757/B747 belongs to heavy and produces strong wake turbulence. 属于重型机会产生强烈尾流The following aircrafts will be affected, 后面的飞机会受到影响there must be sufficient/enough separation between

them. 必须与其保持足够间隔

According to ICAO regulations, the

safe/minimum distance is 5 miles.

根据ICAO规章最小安全距离为5海里

2. If the tower tells you that the distance between you and the B757

is 4 miles, what action would you take? Assume you are already at

the minimum approach speed? Please explain

前面理论内容同上。

时刻观察姿态注意操控，且Prepare for go-around.

3. You are in a B737 taking the active runway after the tower has

cleared a B747 for a takeoff on the same runway in front of you. The

wind is from you left at 6 knots. What would you do? Why?

B757/B747 belongs to heavy and produces strong wake turbulence.

According to ICAO regulations, the safe/minimum separation is 2 mins.

I will wait 2 mins and keep separation to avoid wake turbulence.

4. Assuming you were at a busy airport, while you are entering that

runway, the tower clears you for an IMMIDIATE takeoff on that

runway, a Saab 340. You have notice the B747 in front of you lift off

at about 8000 feet down the runway. Now the tower clears you for a

takeoff and you know your aircraft requires a 2500 feet take off

distance. What should you do? Why?

B757/B747 belongs to heavy and produces strong wake turbulence.

According to ICAO regulations, the safe/minimum separation is 2 mins.

Although the separation is not enough, I will follow ATC instruction and

takeoff immediately. But after airborne, I will request left or right turn to

avoid flying beneath the B747‟s flight path. This will reduce the effect of

are in a B757 taking off behind a B747, both have a heavy call

sign designation. What precaution would you take, if any, following

the B747 ahead of you? Please explain why?

During takeoff, plan to liftoff before the rotation point of the

preceding aircraft and to stay upwind of the touchdown point of the

landing aircraft. If you can’t do this, apply the separation standards

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