91

Practically speaking, the 'heavy' designator ('super' for A380 and An225) is to help enforce separation requirements due to wake turbulence. In case of AF1, it is not as if other aircraft are going to be allowed near it, so the designator is redundant. Regulation wise, FAA JO 7110.65T Section 4. Radio and Interphone Communications, specifically states that ...


46

Ex US Navy pilot here. I flew the S-3 Viking, which refueled via the probe/drogue method, as opposed to the USAF flying boom method. I can confirm that the receiving plane is below the wake turbulence of the tanker, maybe by 8–10 feet. Although, even if you should ride up into the wake, the sensation is perhaps not as violent as you might think....


30

Origin of the vortices Wake turbulence is easy to understand once you know how a wing creates lift: By deflecting the air flowing across it downwards. In this answer, I had used the simplification of just accelerating downwards all the air flowing through a circle with a diameter equal to the wingspan, and leaving all other air unaffected. This helps to ...


29

My understanding, primarily based on this archived NASA document (also linked to on the B757 Wikipedia article), is that there were several issues leading to the decision to make the 757 a special case. First, there were some notable accidents where witnesses seemed to indicate the cause was 757 wake turbulence. Cessna Citation - December 18, 1992 - ...


26

According to ICAO wake turbulence categories, it is a super-heavy aircraft capable of generating correspondingly super-strong wake vortices. Currently the only "super" aircraft are the Airbus A380 and Antonov An-225 (FAA).


26

It is as simple as "tip" vortices, but that is a misnomer. The wing vortices are not really caused by the "tips". They are inherent effect of generating lift over finite wingspan. To generate lift (a force on the plane), the aircraft applies force on the surrounding air (by Newton's third law). Since the air is free to move, this force accelerates it (...


26

Former B-52 crewdog here...The receiver aircraft flies below the wake turbulence of the tanker. In the case of the typical USAF method, using the boom, the receiver aircraft flies into a "contact" position and holds there. The boom operator (boomer) then "flies" to boom to the correct final position, then extends the nozzle into the refueling receptacle, ...


23

The purpose of the "heavy" designator is create situational awareness because of its wake turbulence. There are also different separation requirements when following a heavy aircraft. Since all air traffic around Air Force 1 is likely to be heavily controlled, there's no need to call out that it's a heavy.


18

Qualification: I am a master parachute rigger and I taught sport parachuting for 10 years. The back door of a 747 is actually in a pretty good position - the tail is above the door and the fuselage is narrowing at that point so it's not a complete side exit. A freefall jumper will drop out of the aircraft's wake in under a second so that's not really an ...


13

Paratroopers are sometimes dropped from large cargo carriers planes out of the backdoor (or side door) with little trouble. (right in the wake turbulence) However by the time you open your parachute you will already be well clear of any turbulence caused by the large airplane.


11

The aircraft is either an A380, or AN225. Reference


11

It depends on the size of the preceding aircraft. ICAO PANS-ATM-Doc 4444 Air Traffic Management has some values. 5.8.2 · Arriving aircraft 5.8.2.1 Except as provided for in 5.8.l.l a) and b), the following separation minima shall be applied. 5.8.2.l.l The following minima shall be applied to aircraft landing behind a HEAVY or a MEDIUM aircraft: a) MEDIUM ...


11

The AIM 7-3-9 lists the required separations. Behind a heavy aircraft, the departure hold is 3 minutes and it may not be waived. Behind a small aircraft, the hold may be waived on pilot request only: 3. Additionally, appropriate time or distance intervals are provided to departing aircraft: (a) Two minutes or the appropriate 4 or 5 mile radar ...


10

The tiny mass of air that this device can affect will in no way have the claimed effect on induced drag. This wingtip vortex pseudoscience is just bullshit. What can be observed as a vortex behind the wing is actually the consequence of the vortex sheet rolling up due to downwash behind a lift-generating wing. But air flowing around the tip has almost ...


10

Wake turbulnce occurs when an aircraft is creating lift. Since, the airliner is on the ground, there is no wake turbulence. If you are worried about jet blast from the airliner holding short between the runways, then I would land past the airliner by about 1000 ft. With the airliners engines at idle, there will be minimal jet blast but if the increase ...


10

In general, the heavier an aircraft is, the greater the wake it produces but, it is also less affected by the wake of other aircraft. In particular, an aircraft can always resist the wake turbulence of a lighter category aircraft. It was found that the A380 was not affected by wake turbulence from any aircraft in front, including another A380, down to the ...


10

Well there may be vortex formation on the ground under certain conditions, but it doesn't stick around long enough to really be measured or cause trouble. Any time a wing is producing lift it will generate a wake. This happens even if the wing generates just enough lift to make the aircraft "lighter" but not enough to get it off the ground: Vortices will ...


10

If you look from enough of a distance, the answer is yes. Close up, both will have their own developing wake. The boundary layer leaving wing and tail will leave a speed discontinuity, and the downward moving wing wake will be complemented by a tail wake which will slow down this downward movement directly behind the tail and increase it left and right of ...


10

What you are describing is Unusual Attitude Recovery (UAR) techniques, which are a standard part of the training for every Private Pilot1 Here is a good description of just such an event. Almost all pilots do instinctively want to right the plane first, but as I'll explain below, this is a mistake, and the point of UAR training is to change the pilot's ...


9

Big ones. Wake turbulence is primarily proportional to the aircraft's weight, since this is generally directly related to the size of the aircraft and the amount of air the wings need to move to provide enough lift. Aircraft are categorized with respect to wake turbulence based on their maximum certificated takeoff weights. FAA AC 90-23G describes classes ...


9

You are right that wake turbulence would be a danger when flying behind another aircraft like that. The perspective of the photo makes it hard to see the actual position of the trailing aircraft relative to the ones in front of it. Pilots do this sort of thing in airshows when they fly in formation. The trailing aircraft are generally slightly below the ...


8

Yes, it does appear that the airplanes behind the lead in a formation would be affected by wake turbulence. In reality, there are several factors which contribute to make it not so risky. Airplanes make the formation on high altitudes. Wake Turbulence becomes a bigger issue during takeoff and landing phases. As mentioned on Wikipedia: Wake turbulence is ...


7

Great question! I am far from an expert in supersonic flight, but according to this NASA chat transcript, Ed Haering (an aerospace engineer at NASA's Dryden Flight Research Center in Edwards, Ca. who I would consider to be an expert) answers just this question and says that it isn't a problem for other airplanes: chetman1020: Do sonic booms ever disrupt ...


7

Like to see the fleet and crews talking here. I am a US Navy A7E pilot who flew in the Med aboard the USS Nimitz in the mid-1980's. I served as tanker pilot, and had my share of plugging behind an A6 or A7 at night. Hit a KC-135 once with a flyable boom and that was sweet. If you are tanking off of something like an A6, which I believe was designed with a ...


7

The minimum vertical separation in a holding stack is no different from the minimal vertical separation used elsewhere. This is almost universally 1000 feet. In countries where Reduced Vertical Separation Minima (RVSM) has not been implemented, 2000 feet of vertical separation is required above FL290. 2000 feet is also needed if a non-RVSM equipped aircraft (...


6

Jet Blast is the force or wind generated behind a jet engine, particularly on or before takeoff when high/full power is set, but also when the aircraft is taxiing. When an object moves through air (or some other medium, e.g. a spoon through nutella), air is disturbed. This disturbance or wake is known as wake turbulence. It can also be called jet wash. The ...


6

Practice. Lots of practice. Smaller planes like fighters usually refuel from a hose trailing behind the wing, far enough from (and below) the main body to avoid the worst turbulence. The tanker is completely passive here - the receiving pilot does everything. If it's too turbulent he just backs off and tries again Larger planes use the flying boom method - ...


6

Wake turbulence is caused by an aircraft as it moves through the air, so the turbulence is in the trail of the aircraft. A parachutist isn't going to be behind the aircraft after jumping out of a jumbo jet as there's only doors on the side. Say the airplane has a rear ramp like a 727, the parachutist is very quickly going to drop below the level of any wake ...


6

(YouTube) This is not wake turbulence. This is a hard landing. The smoke from the tires is hot, it rises, hits the fuselage, curls away from it, and then curls back on itself due to the Rayleigh–Taylor instability. (YouTube) A more persistent example. Note the still rising column of smoke.


6

Due to the nature of wake turbulence descending over time and weakening as time goes on, I would say that it's possible that you hit the wake of the 737, and just managed to avoid the A380's wake out of luck. It also depends on the wind direction as to the path of the wake, so it's hard to say in your specific case Skybrary describes crossing wake ...


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