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Small planes are vulnerable to wake turbulence from large planes. In this case the private jet got caught in a tip vortex which exceeded it's roll-control and caused it to flip over. Thankfully it was at a high altitude and managed to recover.

But could a jumbo jet's wake be dangerous to another equal-sized jetliner? Could a Cessna Skyhawk endanger another Skyhawk? I would imagine this is the case takeoff and landing where there is less room for error. But at altitude?

Helicopters at low speeds have much worse downwash than equal-weight planes, so stacking two helicopters vertically may be a better example of danger to your peers.

Edit: A380 vs A380 shows indeed a significant effect.

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  • $\begingroup$ Related: Accident and Serious Incident Reports: WAKE, and detailed explanation in ICAO Doc 9426 (page 280, and part II in recent versions). $\endgroup$
    – mins
    Sep 29, 2023 at 18:21
  • $\begingroup$ I have a single character change - turbulance -> turbulence in the title. But I can't change it because I don't have enough reputation to make a single-character change. Somebody who can do that, please do that. Thank you. $\endgroup$ Jan 28 at 4:19

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Yes, wake turbulence can be dangerous to planes of equal size. Not so much at cruise stage, but during takeoff and landing, yes.

The reason for takeoff, initial climb and landing phase being considerably more dangerous is not so much about the altitude, but because during those phases the airspeed is slower, requiring higher angle of attack to create sufficient lift, thus making the wake vortices considerably more energetic. This is emphasized for takeoff and initial climb due to higher mass of the planes (more fuel).

The most tragic example of danger relating to a heavy classification aircraft flying through the wake turbulence of another heavy class aircraft is the crash of American Airlines flight 587. Even though the crash basically was caused by improper flying technique, wake turbulence was the factor setting the chain of events in motion. However, as pointed out by Bianfable in his comment, while both A300 and B747 carry the Heavy classification, B747 can be, depending on load, more than twice as heavy as the A300.

During cruise, when a higher airspeeds are involved, the energy of wake vortices is spread over greater distance mitigating the effect on other planes.

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    $\begingroup$ While the AAL587 accident was indeed a heavy vs. heavy category match, it should be noted that the 747-400 has more than twice the MTOW of the A300. $\endgroup$
    – Bianfable
    Sep 29, 2023 at 7:01
  • $\begingroup$ That is a good point, A300 is in fact not as comparable to B747 as I originally thought. $\endgroup$
    – Jpe61
    Sep 30, 2023 at 10:51
  • $\begingroup$ So maybe cruise-on-cruise wakes are considered "dangerous" only for large-ish mass ratios. But the more intense slow-speed wakes have been a trigger for a crash at a 2:1 mass ratio. So it's not inconceivable they could pose some sort of hazard at 1:1, especially if the spacing rules were to be ignored. $\endgroup$ Oct 1, 2023 at 20:16
  • $\begingroup$ The danger posed by wake turbulence also varies greatly on the relative angle in which a plane flies through the wake. Perpendicular path will certainly give a rough ride as strong up and downdrafts follow quickly in succession, but flying straight into wake parallelly can easily flip the smaller plane on its back. $\endgroup$
    – Jpe61
    Oct 2, 2023 at 6:14
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If it helps to tune your intuition, consider this. An aircraft experiences drag because it imparts energy to the atmosphere and does this in three ways. It imparts heat energy to the air in its wake by virtue of friction. It imparts kinetic energy by any shock waves that are produced. It imparts kinetic energy by its trailing vortices. In subsonic flow, except close to Mach one, there are no shocks. The most efficient cruise is achieved when the heat energy and kinetic energy are equal, so roughly one half of the engines power output is being poured into those vortices. So, yes, an encounter with the vortex wake of another aircraft of similar size can be very serious. A sufficient distance behind the generating aircraft, the vortices do decay. Interestingly, they do not lose strength (see the contrails persist for miles!), but that energy is spread out over an increasing diameter.

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  • $\begingroup$ Nice point of view. "Interestingly, they do not lose strength but that energy is spread out over an increasing diameter" they eventually change into heat due to friction $\endgroup$
    – sophit
    Oct 1, 2023 at 6:55
  • $\begingroup$ Contrails are not the same phenomenon as wake votices, one cannot draw parallels between those two. The vortices eventually turning into heat is a good description thought. $\endgroup$
    – Jpe61
    Jan 28 at 7:44
  • $\begingroup$ @Jpe61 Contrails ARE wake vortices. And to be sure everything eventually turns into heat. That is why contrails eventually disappear. $\endgroup$
    – Philip Roe
    Feb 17 at 2:06
  • $\begingroup$ Nope @PhilipRoe contrails are water vapor from engines. Look it up. Contrails can last for days. Wake vortices do effect contrails, your might be thinking of that? $\endgroup$
    – Jpe61
    Feb 17 at 22:29
  • $\begingroup$ Why is that water vapor where it is?? $\endgroup$
    – Philip Roe
    Feb 17 at 22:33

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