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Mach 1 in commercial flight. Really!!!?

FinalImpact

FinalImpact

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So, I needed know when to be at the airport and was surprised to watch this software track a Boeing 737-800 and see it hit Mach 1. Plane was a late departure and the Capt apparently decided to make up some time. :eek:

Some literature indicates M 0.785 is a typical cruising speed at 40,000ft. This plane was at 37,000 and traveling at 656 mph... I had no idea a commercial air liner would touch that number at will. Never looked, never thought too much about it. Its pretty cool software take a look if you need to know where / when family and friends are in flight (flightaware).

flightaware.com select a flight and on the specific plane (right) select "speed graph" for continuous updates.

Anyone have any thoughts on this? Is that standard practice?

FWIW: @40,000 feet
Mach 1 = 573knots (kts), 660 mph, or 1062km/h

EDIT: Added a random snapshot of software at work... Its a 737-800 also. Notice the "SPIKE" at 12:52 - speed was 510mph ^604 V 503mph...
56330d1427401990-mach-1-commercial-flight-really-737-800-flightaware-jpg


12:52PM 40.9969 -76.5544 107° East 443 510 23,200 -1,395 FlightAware ADS-B (KMDT)
12:52PM 40.9814 -76.4892 100° East 525 604 22,400 -2,036 FlightAware ADS-B (KFDK)
12:53PM 40.9658 -76.4247 107° East 437 503 21,300 -2,063 FlightAware ADS-B (KLOM)
 
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Interesting - here and elsewhere max speed is given as 588mph, max mach as 0.82. Cruising speed 511mph.

Assuming max mach is about air speed rather than speed over ground then a tailwind of just 68mph would get you to 656mph over ground at full throttle while staying within maximum mach.

I would guess it's more likely that it was a bit more tailwind and a bit less throttle for economy, but maybe airport slots are more expensive than fuel?

Good fun that, thank you!
 
Perhaps we didn't do apples to apples??

Mach is altitude / pressure relative as changes the speed of sound waves....
@40,000 feet
Mach 1 = 573knots (kts), 660 mph, or 1062km/h
VS
@Sea level:
Mach 1 = 660knots (kts), 762 mph, or 1223km/h

I used this: Global Aircraft Speed Converter
 
Can someone explain this; remember that 747 out of LAX which had a flameout, pilot didn't believe the artificial horizon and ignored it falling 30,000 feet and once under the cloud cover ~10,000 feet level off. In this article its said to have reached speeds of 335mph (5G's were experienced), and the plane lost some of its flight controls while falling at high speeds.

Was the damage inflicted by the air density INCREASE at say 20,000 feet as 335mph doesn't seem that fast compared to 737 cruise speed. Obviously they don't do Mach 1 at 20,000 or 10,000 so maybe it is air density? :don'tknow::don'tknow:

From: en.wikipedia.org/wiki/China_Airlines_Flight_006
From: "http://en.wikipedia.org/wiki/China_Airlines_Flight_006" The plane entered a steep dive at a high bank angle. Altitude decreased 10,000 ft (3,000 m) within only 20 seconds, a vertical descent averaging 30,000 feet per minute (150 m/s). The crew and passengers experienced g-forces reaching as much as 5g
Click to expand...
 
FinalImpact said:
Perhaps we didn't do apples to apples??
Click to expand...

I think the app is doing apples/pears by giving you speed over ground (using gps), while the plane's situation is based on it's speed relative to the air around it. The plane can go 588mph or mach 0.82 faster than the air it is flying through, regardless of how fast that air is moving relative to any fixed point
 
As mentioned, it's about the tailwind. The cruising speed for a 737 is around 550 mph, add a tailwind, it can go much faster and vice versa. The flight was heading eastbound so it makes sense. In the northern hemisphere, during the winter months of Nov-Jan the headwinds are the most prevalent, and you can really see how much of a difference it makes by just looking up the same flight going in the opposite direction.

If you track a flight from SEA to NRT, it takes a northern route flying over Alaska, the shortest distance and to avoid much of the headwind as possible. The return trip they jet across a more direct route across the Pacific, a longer distance but they can take advantage of the tailwind.
 
VEGASRIDER said:
As mentioned, it's about the tailwind. The cruising speed for a 737 is around 550 mph, add a tailwind, it can go much faster and vice versa. The flight was heading eastbound so it makes sense. In the northern hemisphere, during the winter months of Nov-Jan the headwinds are the most prevalent, and you can really see how much of a difference it makes by just looking up the same flight going in the opposite direction.

If you track a flight from SEA to NRT, it takes a northern route flying over Alaska, the shortest distance and to avoid much of the headwind as possible. The return trip they jet across a more direct route across the Pacific, a longer distance but they can take advantage of the tailwind.
Click to expand...

^6 thanks, the flight I reference in first post was East to West Denver to PDX. That said, i think they mashed on the throttle a bit!

Check this out: Live Earth Wind speed visual... Earth.nullschool.net
 
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