# Tag Info

44

There is actually some data (albeit limited) on this scenario: On August 21st 1961 this test was performed in a DC-8. When this test was performed they were supersonic for about 16 seconds which took a lot of planning to pull off. You first need to climb higher than the plane typically does to have enough altitude to pull this off, then make sure you ...

16

The TWA Flight 841 accident in 1979 involving a Boeing 727 comes pretty close to your conditions. Not a zero-G dive but an unintended spiral dive starting at 39,000 feet, reaching mach 0.96 at 31,800 feet, becoming a 90 degree nose-down dive at 29,000 feet with total loss of control authority. With speed brakes ineffective, the pilot extended the landing ...

6

After you break the sound barrier, a shock wave will be generated in front of your main wings and tail wings. Though the design of wings on modern planes may hold that situation and can still generate some lift (which is impossible for traditional wings, leading to a fatal stall), the control surfaces on your main wings and tail wings will nearly lose their ...

6

Based on the formula already shown in this answer, we can calculate the TAT (true air temperature), which is the temperature reached at the stagnation point1, from the SAT (static air temperature) and Mach number: $$\frac{\text{TAT}}{\text{SAT}} = 1 + \frac{\gamma - 1}{2} M^2 = 1 + \frac{1}{5} M^2$$ The resulting plot of TAT vs. Mach number at the SAT of -...

5

The engineers ran loose with it You wrote: The Mercure's Wikipedia article - citing Dassault - admits as much, even as it makes the claim that the aircraft was doomed by its short range That is correct, but the statement needs unpacking. After scouring literature on the Mercure, its failure is relegated to literally footnotes. Maybe there're more details ...

4

Could an airliner exceed Mach 1 in a zero-G power dive and safely recover? There is only one answer here and that is NO, especially for the A320 in your example (there are other airliners better suited to tolerate higher transonic speeds). Yes, it's possible to recover from such a condition, but nothing about it would be safe. Recovering from this ...

3

That is because as you approach the transonic regime, the drag on the airframe begins to rise and can reach up to ten times the subsonic drag. after you go supersonic, the drag falls down again- and this makes the transonic regime the worst place to operate a plane from a fuel burn standpoint. So you either stay subsonic, operating below the drag rise point, ...

3

The temperature change is relatively minor, but total air temperature is always much less than the static air temperature in flight, due to surface friction. I have been able to increase fuel temperature in outboard tanks, when fuel recirculation wasn't enough to increase the fuel temp at northern latitudes, by increasing cruise speed by a small margin. It'...

1

Pilots aim on attitude rather than rate. But, with that in mind, the typical touchdown is somewhere around 50-300ft/min. Anything below 200fpm in a B787 tend to feel very smooth (personally I've never seen less than 105fpm, and it was super smooth, as smooth as you can expect), different aircraft feel different. Between 200 to 300, feels normal, and above ...

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