The first airliner to ever break the sound barrier was the DC-8, doing so in a semi-famous dive from 52,000' to 35,000' over the Edwards test range on August 21, 1961.

Could this supersonic dive be planned and reproduced by a suitable flight test crew in a more modern jet transport aircraft?


Why not?

There have been several cases of near-sonic and even supersonic dashes by the Boeing 747, and the damage to the China Airlines Flight 006 elevator was done by landing gear doors which ripped off when the main gear was extended and its doors hit the elevator.

There have been a few unintentional supersonic dives, and in those cases the actions taken by the crew to decelerate caused damage to the aircraft. TWA Flight 841, a Boeing 727 which rolled into a dive, and China Airlines Flight 006 overstressed the airframe, but both aircraft returned to service after repairs.

IAI experience tells me it needs a dive with a nose-down angle of 18° to get a Boeing 747 to Mach 0.98. Since almost all surfaces experience already supersonic flow at this speed, going the step to Mach 1.01 would need not much more, maybe 25°. Pulling up from such a dive by means of the stabilizer should entirely be possible without exceeding g limits.

  • $\begingroup$ Yeah -- I have read (unfortunately, just in a forum) that Boeing flight tested the 747 to Mach 0.99. I suppose all it would take for an intentionally supersonic 747 dive to happen is one Boeing test crew going "Hey, Mach 1 isn't so far away after all..." and coming up with a test plan for taking the 747 there. $\endgroup$ Sep 10 '15 at 14:57
  • $\begingroup$ Who's the IAI and what did they do with the jumbos $\endgroup$
    – Abdullah
    Apr 5 '21 at 15:49
  • $\begingroup$ @Abdullah: Israel Aircraft Industries. I added a link to the text. $\endgroup$ Apr 5 '21 at 16:09
  • $\begingroup$ Gulfstream has also test dove their G500, G600, G650, and G700 airplanes past Mach 0.99 during test flights. It is reasonable to conclude that all of these aircraft would be capable of very briefly breaking the sound barrier during flight in a dive, and still be within a recoverable capability. $\endgroup$ Apr 5 '21 at 18:02
  • 1
    $\begingroup$ Why not? Because the control surfaces become inoperable due to the load exceeding the specs. $\endgroup$ Apr 6 '21 at 10:54

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