Hanscom G-IV Crash - NTSB probable cause
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NTSB VIDEO BRIEFING
You may not have found the NTSB video briefing here:
Not mentioned in the text so far, but mentioned in the video is that the crew observed a Blue rudder limit light as they turned onto the runway.
Apparently, for those that know the aircraft systems, this is a secondary indication that the gust lock is engaged!
You would think that they would have sorted that out before applying power-assuming that they knew their aircraft's systems.
Not mentioned in the text so far, but mentioned in the video is that the crew observed a Blue rudder limit light as they turned onto the runway.
Apparently, for those that know the aircraft systems, this is a secondary indication that the gust lock is engaged!
You would think that they would have sorted that out before applying power-assuming that they knew their aircraft's systems.
Last edited by Machinbird; 13th Sep 2015 at 02:46.
Commanding an aircraft is not part of a popularity contest.
Even if you're flying with your best buddy INSIST on doing it right.
If he wants to take it to the office then fine.
I never went to the office in forty years.
There's a saying I've come across from two Army guys: "The standard you walk past is the standard you accept."
Even if you're flying with your best buddy INSIST on doing it right.
If he wants to take it to the office then fine.
I never went to the office in forty years.
There's a saying I've come across from two Army guys: "The standard you walk past is the standard you accept."
How do they know ?
I looked at the pdf on line and what I does not say is how they know the crew was habitually not performing the required checklist. "the pilots had neglected to perform complete flight control checks before 98% of their previous 175 takeoffs in the airplane, indicating that this oversight was habitual and not an anomaly."
I assume they must have the CVR data somewhere. Is there a requirement to store this data. If so for how long?
There is a lot of blame to go around here. Interesting and scary reading.
20driver
I assume they must have the CVR data somewhere. Is there a requirement to store this data. If so for how long?
There is a lot of blame to go around here. Interesting and scary reading.
20driver
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I assume they must have the CVR data somewhere. Is there a requirement to store this data. If so for how long?
These days many airlines & flight departments will periodically download and analyze QAR data in accordance with their Flight Operations Quality Assurance (FOQA) program. The data is kept in an archival database and is used to provide safety oversight.
FOQA is part of a larger Safety Management System (SMS). It's a pity that this particular operation apparently had an audited SMS in place, but clearly no one really paid attention to basic practices like making sure checklists are being followed.
FOQA and SMS are voluntary in the US although they will soon become mandatory for Part 121 and is already in wide use among airlines and many biz jet ops.
Below the Glidepath - not correcting
The "holes in the cheese" argument is tripped out on every conceivable occasion. Sometimes it's valid, and sometimes it's not. It isn't just the non-aviators here who seem to coveniently ignore that good Captaincy and Airmanship will prevent the holes lining up. If you willfully ignore those 2 key facets to flight safety, at some point the "contributory factors" may catch you out. In this case no less than 4 of the most basic Captaincy and Airmanship gates were missed and the holes lined up. So stop blaming this amorphous factor and accept that poor training and decision making is still a key factor in aircraft accidents.
The "holes in the cheese" argument is tripped out on every conceivable occasion. Sometimes it's valid, and sometimes it's not. It isn't just the non-aviators here who seem to coveniently ignore that good Captaincy and Airmanship will prevent the holes lining up. If you willfully ignore those 2 key facets to flight safety, at some point the "contributory factors" may catch you out. In this case no less than 4 of the most basic Captaincy and Airmanship gates were missed and the holes lined up. So stop blaming this amorphous factor and accept that poor training and decision making is still a key factor in aircraft accidents.
But it reinforces, rather than invalidates, the Swiss cheese model.
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Given that the late abort decision was suicide, could the Horizontal Stab have been trimmed to get it to rotate?
Flying with the controls locked would be friggin dangerous, but it might buy time and opportunity compared to the abort decision.
How the heck are you going to find a flight control issue if you don't cycle the controls? They stopped being defensive pilots long before this accident.
Flying with the controls locked would be friggin dangerous, but it might buy time and opportunity compared to the abort decision.
How the heck are you going to find a flight control issue if you don't cycle the controls? They stopped being defensive pilots long before this accident.
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Given that the late abort decision was suicide, could the Horizontal Stab have been trimmed to get it to rotate?
Flying with the controls locked would be friggin dangerous, but it might buy time and opportunity compared to the abort decision.
You are asking that question on here as a Monday morning quarterback and with lots of hindsight & thinking time. They had seconds to make a decision. The question you ask would take a superior pilot to action & answer. Take a look at the thread about a C140 engine failure on takeoff at 50' where the pilot waggled the wings to drip some fuel into the engine from supposedly empty tanks. I suspect, strongly, that some where deep in his subconscious memory an old sage had dropped that pearl of survival wisdom where it germinated and lay dormant just for that fateful day. In this case there was no such pearl.
Flying with the controls locked would be friggin dangerous, but it might buy time and opportunity compared to the abort decision.
You are asking that question on here as a Monday morning quarterback and with lots of hindsight & thinking time. They had seconds to make a decision. The question you ask would take a superior pilot to action & answer. Take a look at the thread about a C140 engine failure on takeoff at 50' where the pilot waggled the wings to drip some fuel into the engine from supposedly empty tanks. I suspect, strongly, that some where deep in his subconscious memory an old sage had dropped that pearl of survival wisdom where it germinated and lay dormant just for that fateful day. In this case there was no such pearl.
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Interesting question about using trim to rotate. While they might have gotten off the ground and may also have cleared obstacles, additional attempts to free the controls would likely have been just as unsuccessful in the air due to aerodynamic loading on the controls. The end result of an airborne high performance aircraft with no primary flight controls would likely be all aboard perished, plus the impact site at Burlington Mall, Lahey Clinic hospital, scores of residential buildings, etc.
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You are asking that question on here as a Monday morning quarterback and with lots of hindsight & thinking time. They had seconds to make a decision. The question you ask would take a superior pilot to action & answer.
No one is going to write a procedure for rotating an aircraft with locked controls so as to go flying. This aircraft was not supposed to be able to do that in the first place, the throttle was supposed to be limited with the controls locked. The flight crew was supposed to check for free controls before taking the runway, but crap happens. Maybe there would have been sufficient control motion to keep the shiny side up despite the control lock if they could have gone flying.
Know your procedures and follow them accurately. But have some backup plans in your hip pocket. You will be a better pilot for it.
Periodic sampling and compliance analysis of QA data
Originally Posted by from_the_NTSB_report
the airplane’s quick access recorder revealed that the pilots had neglected to perform complete flight control checks before 98% of their previous 175 takeoffs in the airplane, indicating that this oversight was habitual and not an anomaly.
Interesting times.
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Excessive safety?
Two career lab rat, precision military systems, retired.
RE the 98% fail to perform, for what a penny or two might be worth.
It takes about 21 repetitions to develop a new habit. (Including changing a current habit to a new requirement) The 'Oh Yes I need to change that' events are part of the process of changing a habit.
In the current make everything ultra safe policy world cutting a corner most often provides a positive reward for the negative performance.
The saved time, the saved fuel, the saved cost and there is no negative consequence until well after the habit was formed.
Some learned folks in sociology are now examining have we have become so risk adverse we provide far too much positive reinforcement for negative behaviors. First time, no negative effect, second, third,... a very infrequent problem may let you run a long way on thinning ice.
On the gust lock. Not an aircraft control in this case.
NTSB stated that the gust lock was a physical external strap left attached and was visible to ground personnel as they were departing.
Fly safe.
G
RE the 98% fail to perform, for what a penny or two might be worth.
It takes about 21 repetitions to develop a new habit. (Including changing a current habit to a new requirement) The 'Oh Yes I need to change that' events are part of the process of changing a habit.
In the current make everything ultra safe policy world cutting a corner most often provides a positive reward for the negative performance.
The saved time, the saved fuel, the saved cost and there is no negative consequence until well after the habit was formed.
Some learned folks in sociology are now examining have we have become so risk adverse we provide far too much positive reinforcement for negative behaviors. First time, no negative effect, second, third,... a very infrequent problem may let you run a long way on thinning ice.
On the gust lock. Not an aircraft control in this case.
NTSB stated that the gust lock was a physical external strap left attached and was visible to ground personnel as they were departing.
Fly safe.
G
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System description
Originally Posted by gleaf
On the gust lock. Not an aircraft control in this case.
NTSB stated that the gust lock was a physical external strap left attached and was visible to ground personnel as they were departing.
NTSB stated that the gust lock was a physical external strap left attached and was visible to ground personnel as they were departing.
From a system description posted by Mutt on the other thread on this subject:
A.Surface Lock System:
(See Figure 26)
A single T-shaped handle, located on the right side of the cockpit center
pedestal and labeled GUST LOCK, controls the gust lock system. A spring
loaded trigger is incorporated in the gust lock handle to prevent the handle
from inadvertently being pulled. Releasing the trigger and then raising and
pulling the GUST LOCK handle aft actuates conventional mechanical
linkage consisting of cables. springs. latches and a bungee rod. Moving the
ailerons and rudder to the neutral position and the elevator to the trailing
edge down position allows the gust lock to engage and lock the flight
controls as their linkages reach the locking position. Releasing the trigger
and then lowering the GUST LOCK handle releases the gust lock.
Safety Features prevent the gust lock from inadvertently engaging or a
failure of the system preventing gust lock release.With the gust look
released, the bungee rod acts as a fixed rod to prevent inadvertent flight
control locking. If the gust lock fails when engaged, the springs will unlock
the gust took
B.Mechanical Power Lever interlock:
A mechanical interlock is incorporated in the GUST LOCK handle
mechanism that restricts simultaneous movement of the power levers to a
maximum of six percent above ground idle with the gust lock engaged.
Force applied to advance both power levers simultaneously cannot
override the interlock. To prevent any hydraulic forces acting upon an
engaged gust lock. the gust lock should be released prior to engine starting
and not engaged until all hydraulic pressures read zero.
(See Figure 26)
A single T-shaped handle, located on the right side of the cockpit center
pedestal and labeled GUST LOCK, controls the gust lock system. A spring
loaded trigger is incorporated in the gust lock handle to prevent the handle
from inadvertently being pulled. Releasing the trigger and then raising and
pulling the GUST LOCK handle aft actuates conventional mechanical
linkage consisting of cables. springs. latches and a bungee rod. Moving the
ailerons and rudder to the neutral position and the elevator to the trailing
edge down position allows the gust lock to engage and lock the flight
controls as their linkages reach the locking position. Releasing the trigger
and then lowering the GUST LOCK handle releases the gust lock.
Safety Features prevent the gust lock from inadvertently engaging or a
failure of the system preventing gust lock release.With the gust look
released, the bungee rod acts as a fixed rod to prevent inadvertent flight
control locking. If the gust lock fails when engaged, the springs will unlock
the gust took
B.Mechanical Power Lever interlock:
A mechanical interlock is incorporated in the GUST LOCK handle
mechanism that restricts simultaneous movement of the power levers to a
maximum of six percent above ground idle with the gust lock engaged.
Force applied to advance both power levers simultaneously cannot
override the interlock. To prevent any hydraulic forces acting upon an
engaged gust lock. the gust lock should be released prior to engine starting
and not engaged until all hydraulic pressures read zero.
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This aircraft was not supposed to be able to do that in the first place, the throttle was supposed to be limited with the controls locked.
In my list of slices with holes lining up from the time they entered the runaway I forgot one. I do not know about the 'throttle inhibiting system' but the PF did state that he could not achieve planned thrust manually, they then engaged A/T and it also failed to achieve planned thrust. This could be interpreted as an inhibition, perhaps not to manufacturer's spec.
However, the missing slice would have been the lack of expected and experienced acceleration. Surely they knew this a/c and airport. They should have sensed it was all going too slowly and the end of the runway was getting closer than usual. Not only was the RTO delayed for an inexplicable reason, by BOTH PIC & SIC, who has brakes, but it would have happened further down there runway anyway. They were in a double whammy situation. Delayed RTO and with less runway than expected.
I still can not understand the lack of self preservation in their awareness. You are about to go aviating into a hostile environment, where Mother nature and gravity are trying to deter you from such arrogant intrusion, and yet they tried to do so with dulled senses. Hm?
In my list of slices with holes lining up from the time they entered the runaway I forgot one. I do not know about the 'throttle inhibiting system' but the PF did state that he could not achieve planned thrust manually, they then engaged A/T and it also failed to achieve planned thrust. This could be interpreted as an inhibition, perhaps not to manufacturer's spec.
However, the missing slice would have been the lack of expected and experienced acceleration. Surely they knew this a/c and airport. They should have sensed it was all going too slowly and the end of the runway was getting closer than usual. Not only was the RTO delayed for an inexplicable reason, by BOTH PIC & SIC, who has brakes, but it would have happened further down there runway anyway. They were in a double whammy situation. Delayed RTO and with less runway than expected.
I still can not understand the lack of self preservation in their awareness. You are about to go aviating into a hostile environment, where Mother nature and gravity are trying to deter you from such arrogant intrusion, and yet they tried to do so with dulled senses. Hm?
So who was watching the store
Peekay4 - thanks for the reply.
My question is - what was this audit organization doing? I'm sure they sent in a bill every year or whatever, but what did they do? Like the pilots it seems they were captured by habit, signing off without looking. I have experience with this happening in my field. Supervisors signing off on failing test reports because they always see passing tests.
To me it looks like the killer here was too much familiarity. Crew worked together for eons, no hostile outsiders, or new perky book trained new crew, to upset the well greased cart. Wouldn't surprise me one bit if the auditors visit was an occasion for a nice lunch out on the owners tab.
Makes you question how SMS is supposed to work. Maybe some unannounced visits by some nosey parker with a grudge from the local XAA who has no financial stake in the process is what is needed.
Sad thing is the owners, who were literally along for the ride, would have no doubt paid whatever they were told was needed to keep them, and their families, safe.
Contrary to what many on here would have you believe, its not just about spending more.
My question is - what was this audit organization doing? I'm sure they sent in a bill every year or whatever, but what did they do? Like the pilots it seems they were captured by habit, signing off without looking. I have experience with this happening in my field. Supervisors signing off on failing test reports because they always see passing tests.
To me it looks like the killer here was too much familiarity. Crew worked together for eons, no hostile outsiders, or new perky book trained new crew, to upset the well greased cart. Wouldn't surprise me one bit if the auditors visit was an occasion for a nice lunch out on the owners tab.
Makes you question how SMS is supposed to work. Maybe some unannounced visits by some nosey parker with a grudge from the local XAA who has no financial stake in the process is what is needed.
Sad thing is the owners, who were literally along for the ride, would have no doubt paid whatever they were told was needed to keep them, and their families, safe.
Contrary to what many on here would have you believe, its not just about spending more.
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The really slow uptake by the crew on the scope of their problem almost looks like some sort of debilitation.
I'll be anxiously awaiting the full accident report in a few weeks to give that area particularly close scrutiny.
Of course, that critical gust lock lever was hiding in the darkened cockpit, in the wrong position, just waiting to cause trouble.
The elevator was locked in the nose down position. Really hard to believe that no one gave the yoke even a tug before adding power.
I'll be anxiously awaiting the full accident report in a few weeks to give that area particularly close scrutiny.
Of course, that critical gust lock lever was hiding in the darkened cockpit, in the wrong position, just waiting to cause trouble.
The elevator was locked in the nose down position. Really hard to believe that no one gave the yoke even a tug before adding power.
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Originally Posted by 20driver
My question is - what was this audit organization doing?
Audits done by a safety regulator should be nothing more of confirmation - to the operators - that they are doing a good job.
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My question is - what was this audit organization doing?
IS-BAO is really a set of best practices. E.g., among others, IS-BAO requires that an SMS is established; that a formal training program must exist; and more relevant to this accident, that SOPs and checklists are to be followed.
There are different stages (levels) to an IS-BAO audit, but basically the audit is primarily a document checking exercise.
E.g., on the use of checklists, the auditor might see that: 1) the company's FOM requires use of checklists; 2) current and correct checklists are onboard the aircraft; and 3) that the company pilots must take recurrent (annual) proficiency training at Flight Safety including proper use of checklists.
Based on documentation of those three things, the auditor then passes the checklist requirement.
But what the auditor has not done is to personally fly with the pilots to see if they actually use checklists, since in-flight inspection is not required for an IS-BAO audit. Nor has the auditor gone through the FOQA data him/herself to see if there's evidence that checklist items are being missed.
These are things which are expected to be done by the flight department internally. But one problem with small ops is the lack of segregation of duties. It's difficult to police yourself.