Qantas747300
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B707 VMC Accident In The Past.

Fri Dec 07, 2012 1:19 am

I am trying to source the accident behind a VMC diagram. I believe it was a B707 that experienced a loss of control due to excessive bank (following engine failure perhaps) which resulted in a vertical fin stall.

Countless hours of research hasn't sourced what I am after, thus, you have control.

[Edited 2012-12-06 17:20:33]
 
AJ
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RE: B707 VMC Accident In The Past.

Fri Dec 07, 2012 5:21 am

 
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zeke
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RE: B707 VMC Accident In The Past.

Fri Dec 07, 2012 6:16 am

Quoting Qantas747300 (Thread starter):
I am trying to source the accident behind a VMC diagram.

Are you able to post the picture ? some USAF manuals used a picture of an aircraft that looked like a 707 (KC-135) to illustrate points.
We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
 
Qantas747300
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RE: B707 VMC Accident In The Past.

Fri Dec 07, 2012 8:08 pm

AJ,
Thank you. However the study that I refer to was published by the FAA regarding an incident investigated by the NTSB. Unfortunately, no further information.

The RAAF accident apparently closely resembled the incident that I seek information on.
 
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747classic
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RE: B707 VMC Accident In The Past.

Fri Dec 07, 2012 9:52 pm

I only am aware of 707 VMC problems in 1959, that were at last solved by modifying (increasing the height of the vertical tail.
British certification requirements relating to engine-out go-arounds forced Boeing to increase the height of the tail fin on all 707 variants, as well as add a ventral fin, which was retrofitted on earlier −120 and −220 aircraft. These modifications also aided in the mitigation of dutch roll by providing more stability in yaw.
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sdf880
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RE: B707 VMC Accident In The Past.

Fri Dec 07, 2012 9:58 pm

TWA lost a 707-331C Freighter VMC while doing some training at ACY. I believe this was in the late 60's
 
KELPkid
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RE: B707 VMC Accident In The Past.

Sat Dec 08, 2012 1:57 am

Quoting Qantas747300 (Thread starter):
which resulted in a vertical fin stall.

How in the hell do you do that?    It never entered my mind that was even possible, unless you are doing an extreme maneuver like a lomkovac...

In a typical Vmc accident, you just happen to get the aircraft below the speed at which the rudder has the authority to counteract the yaw due to assymetrical thrust... as far as I know, the rudder is still creating lift. If you find it happening to you in real life, the quickest way to recover is to throttle back the good engine, point the nose down, and pick up airspeed (assuming you aren't really low, like base to final traffic pattern turn low  Wow! )
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Jetlagged
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RE: B707 VMC Accident In The Past.

Sat Dec 08, 2012 2:19 am

Quoting KELPkid (Reply 6):
How in the hell do you do that?

Generating a sideslip angle of more than the fin stall angle, about 14 degrees or thereabouts. If the aircraft was rolling the fin AOA could be effectively increased, making a stall happen at lower sideslip.

Quoting KELPkid (Reply 6):
If you find it happening to you in real life, the quickest way to recover is to throttle back the good engine, point the nose down, and pick up airspeed

That's fine in a steady state case where you've chosen to reduce thrust on one engine, a training scenario. With a real engine failure you might have to reduce thrust on the good engine to get directional control back. But increasing airspeed is always a good idea.
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Qantas747300
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RE: B707 VMC Accident In The Past.

Sat Dec 08, 2012 4:04 pm

This accident set the foundation for certification requirements of bank not exceeding 5 degrees for VMC certification.
 
SAAFNAV
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RE: B707 VMC Accident In The Past.

Sat Dec 08, 2012 6:02 pm

Quoting KELPkid (Reply 6):

How in the hell do you do that? It never entered my mind that was even possible, unless you are doing an extreme maneuver like a lomkovac...

The C-130 is quite prone to a 'Fin Stall' below VMCA2. I believe some have gone down due to this phenomena
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scarebus03
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RE: B707 VMC Accident In The Past.

Sat Dec 15, 2012 9:31 pm

No faults found......................

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