Supersonic Dive
I own a flight simulator and one day while I was piloting a
747-400, the plane went out of control. Frantically I
switched to full throttle, but the aircraft continued to dive. To my atonishment, the speed of the
aircraft shown on the instrument panel appeared to be Mach 1.11. Is that possible?
- question from Tieo Jing Jin
As was alluded to in a previous question on supersonic dives,
the transition to supersonic flight is marked by large increases in pressure forces that most subsonic aircraft
are not designed to withstand. While I am not familiar with the exact structural capabilities of the 747, my guess
is that it does have a beefy enough structure to survive a brief excursion into supersonic flight. However, the
shock waves formed above Mach 1 would likely do damage to critical flight controls making the plane difficult, if
not impossible, to control. The plane would then probably enter a fatal dive reaching even higher speeds and
encountering forces that would almost surely tear the aircraft apart. Commercial jetliners have been known to
reach supersonic speeds in accidents. For example, TWA Flight 800, the Boeing 747 that exploded off Long Island in
1996, was broken in two by a fuel tank explosion. The aft section of the aircraft still had wings and engines
attached and continued to fly even after the nose had been broken off. Once the wings stalled after reaching too
high of an angle of attack, the aft portion of the plane began to plummet
and reached supersonic speeds. The forces induced by this supersonic dive were so intense that the wings were
ripped off and the fuselage disintegrated before hitting the water.
Let me briefly clarify one point. Almost any aircraft could probably surpass Mach 1 if it weighed enough and was
in a steep enough dive. The question is whether or not the plane could survive the trip. Most propeller-powered
aircraft or subsonic jets would not because they are not built to survive the stresses of supersonic flight.
- answer by Joe Yoon, 18 November 2001
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