Virgin Galactic SpaceShip Two crashed?

[Eric Mc]

And me.

[Eric Mc]

RYH64E said:

There's always the risk of explosion with rockets. As you know, NASA managed to lose two shuttles and an Antares rocket exploded shortly after launch just the other week, it's a dangerous business.

As I understand it, prior to this incident the major safety fears concerned the propellant used in the rocket and it's relatively unsophisticated design, aerodynamic failure is just another worry to add to all the other worries imo.

Firstly - neither Shuttles were destroyed in explosions. Read the accident reports and you will see what did them in.

Having said that, the Shuttle was an inherently unsafe design, even by normal rocket standards.

The rocket technology being used in Spaceship Two is actually relatively conservative - and it is looking increasingly like it played no part in this accident.

[Bonefish Blues]

doogz said:

shouldbworking said:

The X-15 after it's mach 6.72 flight - http://www.youtube.com/watch?v=wHuBsBOF4R8

I think they were bloody lucky to get down alive.

Fuuuuuuu......

This - beyond lucky.

ETA
That is incomprehensibly fast, at least to my tiny brain.

Edited by Bonefish Blues on Monday 3rd November 13:21

[Civpilot]

hornetrider said:

mcdjl said:

MartG said:

"NTSB's press conference on SpaceShipTwo accident just finished.
"The vehicle had a nominal release followed by a nominal Ignition.
Approximately 9 seconds after ignition, the "feather" parameters changed from lock to unlock.
Approximately 2 seconds later, just above Mach 1.0, feathers moved toward the extended position even though the “feather” handle was not moved, after which the telemetry data terminated.
Normal procedures are to unlock feathers after Mach 1.4 so aerodynamic forces do not extend feathers prematurely
Review of cockpit forward looking camera shows that the feather was unlocked by the copilot
Engine burn was nominal up until feather extension""

So am I understanding it right if i say that the big tailplane came up while the rocket was on? Presumably then causing the whole craft to pitch up and 'loop' almost on its own length causing it to break up?

As a layman, that's what it sounds like to me.

pretty much matches what you can appear to see in the photos (nose over tail tumble). The question is why did the Co-Pilot switch the feathers to unlock at Mach1.0 and not wait for Mach1.4 to be passed?. They are saying that the feathers are locked until after 1.4 to avoid aerodynamic forces pushing them to extend. Then they are saying that after they were unlocked they extended "without command"...

It really does horribly sound like co-pilot error was the main contribution to this accident.

[jammy_basturd]

If I'm reading into this right (and I'm a real layman when it comes to this stuff), but it wouldn't have mattered whether the co-pilot had unlocked the feathers at Mach 1.0 or Mach 1.4 - they still extended "to the second stage" without pilot command when they shouldn't have.

At what point should the feathers extend?

[Dr Jekyll]

Perhaps the reason it isn't supposed to be unlocked until mach 1.4 is that the airflow at lower speeds could cause uncommanded operation.

[jammy_basturd]

Dr Jekyll said:

Perhaps the reason it isn't supposed to be unlocked until mach 1.4 is that the airflow at lower speeds could cause uncommanded operation.

In which case, surely the first line of code would read - if air_speed is less than X, do not extend feathers!

[Dr Jekyll]

That is the point though, they were not extended by command, they just became extended, perhaps blown into an extended position by transonic airflow.

[RobGT81]

I suspect on the next aircraft, the lock will be locked with airspeed. Sounds like a Human Factors classic.

[CrutyRammers]

jammy_basturd said:

If I'm reading into this right (and I'm a real layman when it comes to this stuff), but it wouldn't have mattered whether the co-pilot had unlocked the feathers at Mach 1.0 or Mach 1.4 - they still extended "to the second stage" without pilot command when they shouldn't have.

At what point should the feathers extend?

Well after it's reached the top of the climb I believe - they stabilise the craft on its way back down.

[Scuffers]

RYH64E said:

There's always the risk of explosion with rockets. As you know, NASA managed to lose two shuttles and an Antares rocket exploded shortly after launch just the other week, it's a dangerous business.

the rocket that failed last week was SFA to do with NASA

they are a private company using Russian rocket motors built in the 50's.

[jammy_basturd]

Dr Jekyll said:

That is the point though, they were not extended by command, they just became extended, perhaps blown into an extended position by transonic airflow.

Ah, by command I assumed they meant human command rather than computer command.

[Bonefish Blues]

Scuffers said:

RYH64E said:

There's always the risk of explosion with rockets. As you know, NASA managed to lose two shuttles and an Antares rocket exploded shortly after launch just the other week, it's a dangerous business.

the rocket that failed last week was SFA to do with NASA

they are a private company using Russian rocket motors built in the 50's.

I didn't read RYH as saying the failure last week was anything to do with NASA.

[Moonhawk]

Article from Sky News suggesting potential pilot error. They say the re-entry system was deployed early - but it doesn't appear to be due to a fault. Cockpit camera footage apparently shows one of the pilots moving the lever out of the 'locked' position.

http://news.sky.com/story/1365606/virgin-galactic-...

[Civpilot]

jammy_basturd said:

Dr Jekyll said:

That is the point though, they were not extended by command, they just became extended, perhaps blown into an extended position by transonic airflow.

Ah, by command I assumed they meant human command rather than computer command.

Human command or not, they would not have extended if there were locked as they should have been. However the Co-pilot manually unlocked them using a physical lever before the craft had passed the magic 1.4Mach. Below 1.4Mach there is a high chance air pressure could force them into the extended feathered position without crew command. Don't think it was a computer failure at all but complete aero effect by the sounds of things.

They stay locked below 1.4 for a very specific reason, and that reason appears to have been horribly demonstrated here.

[Magog]

Totally different situation, aircraft and aerodynamics but these initial reports remind me of BEA 548 in some ways.

[Eric Mc]

Funilly enough, that thought had literally crossed my a mind a few seconds ago. Only in this case we have camera and probably lots of telemetry evidence as to what actually happened.

The question, just like on BE548, will be, why?

[KTF]

If it only takes a matter of seconds to go from mach 1 to 1.4, maybe the pilot was slightly too quick to pull the unlock lever?

[Eric Mc]

Sounds like it.

[hornetrider]

I would have thought the deploying of the feather would happen in a later part of the flight profile after they've looped up to maximum altitude, which is a fair bit longer than a 'few seconds' after the rocket burn starts and begins to accelerate them.

Caveat: IANAA