Gulfstream IV in Bedford MA
OFBSLF
For what it's worth it was the middle section of this article which made me link the events.
Gulfstream G650 Accident Report | The House of Rapp
I have no idea if this has any bearing. The 450 looks to have had this issue way back, but it was corrected.
For what it's worth it was the middle section of this article which made me link the events.
Gulfstream G650 Accident Report | The House of Rapp
I have no idea if this has any bearing. The 450 looks to have had this issue way back, but it was corrected.
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Yes.
Part 91.609
Part 91.609
c)(1)No person may operate a U.S. civil reg-istered, multiengine, turbine-powered airplane or rotorcraft having a passenger seating configura-tion, excluding any pilot seats of 10 or more that has been manufactured after October 11, 1991, unless it is equipped with one or more approved flight recorders that utilize a digital method of re-cording and storing data and a method of readily retrieving that data from the storage medium, that are capable of recording the data specified in Ap-pendix E to this part, for an airplane
(e) Unless otherwise authorized by the Admin-istrator, after October 11, 1991, no person may operate a U.S. civil registered multiengine, tur-bine-powered airplane or rotorcraft having a pas-senger seating configuration of six passengers or more and for which two pilots are required by type certification or operating rule unless it is equipped with an approved cockpit voice recorder
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Susier,
The issue with the G650/GIV you are referring to was the flight engineers incorrectly calculating the V2 speeds too high as well as making an incorrect assumption as to the stall AOA in ground effect. The net result of this was that the flight test crews were making aggressive rotations and steep climb outs in an attempt to not exceed the targeted V2 speeds and achieve the lowest possible balanced field length numbers for the aircraft. In the case of the 650 program this resulted in several wing drops during flight testing that were initially attributed to incorrect pilot technique, it took a tragic accident to "wake up" the engineers and get them to re-examine their calculations and uncover their erroneous assumptions regarding in ground effect stall AOA and V2 speeds. As Susier correctly points out the 650 accident had nothing to do with its flight control system, rather just incorrect performance calculations.
In the case of this GIV accident the fact that the aircraft appears to have come to rest (with considerable energy) some 2,000 ft beyond the departure end of a 7,011 ft runway makes me think this may not have been an aborted take-off over run. For a relatively short flight from Bedford to Atlantic city it is likely the aircraft only had a 10,000lb fuel load which would result in a BFL less than 4,000ft.
The issue with the G650/GIV you are referring to was the flight engineers incorrectly calculating the V2 speeds too high as well as making an incorrect assumption as to the stall AOA in ground effect. The net result of this was that the flight test crews were making aggressive rotations and steep climb outs in an attempt to not exceed the targeted V2 speeds and achieve the lowest possible balanced field length numbers for the aircraft. In the case of the 650 program this resulted in several wing drops during flight testing that were initially attributed to incorrect pilot technique, it took a tragic accident to "wake up" the engineers and get them to re-examine their calculations and uncover their erroneous assumptions regarding in ground effect stall AOA and V2 speeds. As Susier correctly points out the 650 accident had nothing to do with its flight control system, rather just incorrect performance calculations.
In the case of this GIV accident the fact that the aircraft appears to have come to rest (with considerable energy) some 2,000 ft beyond the departure end of a 7,011 ft runway makes me think this may not have been an aborted take-off over run. For a relatively short flight from Bedford to Atlantic city it is likely the aircraft only had a 10,000lb fuel load which would result in a BFL less than 4,000ft.
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Aircraft involved was a 2000 build G-IVSP
It's AOC is SK Travel Limited Liability Corporation
SK Travel LLC is owned by Emil W. Solimine & Lewis Katz both from Livingston NJ
(Lewis Katz was on board)
Was based KILG, New Castle, DE
It's AOC is SK Travel Limited Liability Corporation
SK Travel LLC is owned by Emil W. Solimine & Lewis Katz both from Livingston NJ
(Lewis Katz was on board)
Was based KILG, New Castle, DE
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Susier,
I hope the Rapp.org article didn't give you the impression that Gulfstreams are poorly designed or prone to random stalls. They aren't.
What I was trying to convey with the post was that the G-IV test program suffered from a wing drop problem during OEI continued-takeoff testing whose cause was also attributed incorrectly by the engineers. In other words, it's not the aircraft that is at fault, but rather some of the assumptions made about it during testing.
Of course, that's exactly why testing is performed: to validate those assumptions. On the 650, they computed the wrong critical AOA in ground effect. On the G-IV, it's less clear about why the wing stall occurred (Mr. Johnson's account was given more than a quarter century after the test program ended), but they solved the issue with vortex generators.
My question was: give what happened with the G650, is it possible the IGE critical angle was also mis-computed on the G-IV? It seems that even Gulfstream didn't realize how different the critical AOA can be in ground effect versus in free air. I was not aware of that either. Nobody teaches you that the critical AOA is different, but if anything I would expect the angle to be higher, not lower, because performance is generally enhanced in ground effect.
Anyway, I hope that clears it up a bit.
I hope the Rapp.org article didn't give you the impression that Gulfstreams are poorly designed or prone to random stalls. They aren't.
What I was trying to convey with the post was that the G-IV test program suffered from a wing drop problem during OEI continued-takeoff testing whose cause was also attributed incorrectly by the engineers. In other words, it's not the aircraft that is at fault, but rather some of the assumptions made about it during testing.
Of course, that's exactly why testing is performed: to validate those assumptions. On the 650, they computed the wrong critical AOA in ground effect. On the G-IV, it's less clear about why the wing stall occurred (Mr. Johnson's account was given more than a quarter century after the test program ended), but they solved the issue with vortex generators.
My question was: give what happened with the G650, is it possible the IGE critical angle was also mis-computed on the G-IV? It seems that even Gulfstream didn't realize how different the critical AOA can be in ground effect versus in free air. I was not aware of that either. Nobody teaches you that the critical AOA is different, but if anything I would expect the angle to be higher, not lower, because performance is generally enhanced in ground effect.
Anyway, I hope that clears it up a bit.
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thrust reversers...
Has anyone noticed that the thrust reverser on the right engine in missing? Take a look at the picture:
http://c.o0bg.com/rf/image_960w/Bost...crash5_met.jpg
Looking at it close up, it is clear the the reverser is missing from the right engine, but is in place on the left engine.
Thoughts???
http://c.o0bg.com/rf/image_960w/Bost...crash5_met.jpg
Looking at it close up, it is clear the the reverser is missing from the right engine, but is in place on the left engine.
Thoughts???
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NTSB briefing today
I just watched the NTSB briefing at Hanscom.
They said the flap setting in the cockpit was set at 10 degrees
They have not located the cvr or data recorder as yet.
What I did see from the video was black tire marks for about 500-700 feet towards the end of the runway
With heavy darker tire marks for about a foot every 10 feet or so.
The engines looked intact and didn't see any reversers deployed. Not sure if they have clam shells on the RR Tays.
Captain had 18,000 hours and FO had 11,000 hours.
They said the flap setting in the cockpit was set at 10 degrees
They have not located the cvr or data recorder as yet.
What I did see from the video was black tire marks for about 500-700 feet towards the end of the runway
With heavy darker tire marks for about a foot every 10 feet or so.
The engines looked intact and didn't see any reversers deployed. Not sure if they have clam shells on the RR Tays.
Captain had 18,000 hours and FO had 11,000 hours.
Last edited by OldCessna; 2nd Jun 2014 at 22:21. Reason: Fact corections
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thank you old cessna
that seems to answer the flap question. though oddly put that the flaps were set in the cockpit to 10. wondering if the flaps were actually at 10.
but it does seem likely a late abort happened (I like the term abort better than reject, though I know reject has been around for so long).
does hanscom field have phenolic foam over run? (crushable concrete)
thanks again old cessna
that seems to answer the flap question. though oddly put that the flaps were set in the cockpit to 10. wondering if the flaps were actually at 10.
but it does seem likely a late abort happened (I like the term abort better than reject, though I know reject has been around for so long).
does hanscom field have phenolic foam over run? (crushable concrete)
thanks again old cessna
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The NTSB briefer made specific mention that the cockpit flap setting was 10 degrees.
They will be checking the jackscrews and recorder to correlate.
The braking wheel marks on the runway were perfectly straight. The nose gear assembly was separated ahead of the aircrafts final resting spot and looked pretty intact.
NTSB just found the CVR and Data Recorder
They will be checking the jackscrews and recorder to correlate.
The braking wheel marks on the runway were perfectly straight. The nose gear assembly was separated ahead of the aircrafts final resting spot and looked pretty intact.
NTSB just found the CVR and Data Recorder
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I have flown into Hanscom several times over the last 30 years. Its civilian and AF mix. Raytheon is nearby and a host other defense contractors.
Very good ATC although if you are not familiar with the locale it can be enlightening.
A familiar instruction is "Turn left at HoJo's"
Alright if you know Howard Johnsons has an orange roof!
Don't recall any foam or other stuff at end of runway.
It's a very busy airport but very well operated. My take!
Very good ATC although if you are not familiar with the locale it can be enlightening.
A familiar instruction is "Turn left at HoJo's"
Alright if you know Howard Johnsons has an orange roof!
Don't recall any foam or other stuff at end of runway.
It's a very busy airport but very well operated. My take!
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Has anyone noticed that the thrust reverser on the right engine in missing? Take a look at the picture:
http://c.o0bg.com/rf/image_960w/Bost...crash5_met.jpg
Looking at it close up, it is clear the the reverser is missing from the right engine, but is in place on the left engine.
Owen,
The thrust reverse's are fully intact in the picture you posted. The only thing missing is the close out cover on the right actuator from what I can see.
that seems to answer the flap question. though oddly put that the flaps were set in the cockpit to 10. wondering if the flaps were actually at 10
glendalegoon,
On the GIV it is not uncommon to takeoff flaps 10 (think there was a whole tread on this some time ago). The aircraft also will give you a configuration warning if the flap are not at least 10 degrees and the throttles are advanced..... It is possible they forgot to set flaps 20 when they taxied out and only had them at flaps 10. It is very common to taxi in with flaps left at 10 so you can inspect the flap tracks actuators during the walk around. But I would suspect something else other than flaps, or in combination with, because even if they wanted 20 and only had 10 the aircraft would have flown with no problems, the runway is plenty long enough.
http://c.o0bg.com/rf/image_960w/Bost...crash5_met.jpg
Looking at it close up, it is clear the the reverser is missing from the right engine, but is in place on the left engine.
Owen,
The thrust reverse's are fully intact in the picture you posted. The only thing missing is the close out cover on the right actuator from what I can see.
that seems to answer the flap question. though oddly put that the flaps were set in the cockpit to 10. wondering if the flaps were actually at 10
glendalegoon,
On the GIV it is not uncommon to takeoff flaps 10 (think there was a whole tread on this some time ago). The aircraft also will give you a configuration warning if the flap are not at least 10 degrees and the throttles are advanced..... It is possible they forgot to set flaps 20 when they taxied out and only had them at flaps 10. It is very common to taxi in with flaps left at 10 so you can inspect the flap tracks actuators during the walk around. But I would suspect something else other than flaps, or in combination with, because even if they wanted 20 and only had 10 the aircraft would have flown with no problems, the runway is plenty long enough.
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noneya
thanks for the flap info. as you know there have been other types that did have configuration warning systems that didn't work right.
I imagine with fuel for atlantic city (not much) the plane might have even gotten airborne with no flaps (guess, no book), though I do not suggest anyone would have done this on purpose.
guessing the fuel req'd for atlantic city would have been less than 12000 lbs.
what do you think?
I couldn't link to the photos.
thanks for the flap info. as you know there have been other types that did have configuration warning systems that didn't work right.
I imagine with fuel for atlantic city (not much) the plane might have even gotten airborne with no flaps (guess, no book), though I do not suggest anyone would have done this on purpose.
guessing the fuel req'd for atlantic city would have been less than 12000 lbs.
what do you think?
I couldn't link to the photos.
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I'm not sure of the etiquette of just posting the names here, but I can't be the only one here who's been waiting and wondering if the phone is going to ring.
The article name says it all:
Crew in Hanscom crash identified
The article name says it all:
Crew in Hanscom crash identified
Has anyone noticed that the thrust reverser on the right engine in missing? Take a look at the picture: http://c.o0bg.com/rf/image_960w/Bost...crash5_met.jpg Looking at it close up, it is clear the the reverser is missing from the right engine, but is in place on the left engine. Owen, The thrust reverse's are fully intact in the picture you posted. The only thing missing is the close out cover on the right actuator from what I can see. that seems to answer the flap question. though oddly put that the flaps were set in the cockpit to 10. wondering if the flaps were actually at 10 glendalegoon, On the GIV it is not uncommon to takeoff flaps 10 (think there was a whole tread on this some time ago). The aircraft also will give you a configuration warning if the flap are not at least 10 degrees and the throttles are advanced..... It is possible they forgot to set flaps 20 when they taxied out and only had them at flaps 10. It is very common to taxi in with flaps left at 10 so you can inspect the flap tracks actuators during the walk around. But I would suspect something else other than flaps, or in combination with, because even if they wanted 20 and only had 10 the aircraft would have flown with no problems, the runway is plenty long enough. J
Yes, the R/H engine T/R is present. The outboard stang fairing that covers the actuator has been torn off, but both upper and lower doors are there. The lower door appears to be hanging down a few inches. Based on their appearance in the photo, it's difficult to say if they had been deployed or not. During ground maintenance, if we deploy them, and then shut off pressure from the hydraulic ground service cart -- after a few minutes, (once the pressure in the aircraft hydraulic lines has dropped to zero), the doors can be pushed closed by hand. Takes a bit of muscle power, but definitely do-able.
I would think that with the disintegration of the airframe as the aircraft departed the runway, the hydraulic systems would have been breached almost immediately, and with the loss if pressure, combined with the rapid deceleration of the aircraft, the T/R doors could have swung forward and shut, even if they had been deployed. Then again, perhaps they never were deployed in the first place. Hopefully the FDR will shed some light.
Flaps 10 or 20 are both authorized for takeoff, though I believe a flaps 20 takeoff is far more common. However, during the crew's preflight initialization of FMS performance data, on the Takeoff Init page 3, they have to enter which flap setting is going to be used. As far as I know, the default flap setting on this page is Flaps 20, and the crew would have to specifically hit the 3R line select key "OR 10" to tell the perf computer that a flaps 10 takeoff is planned.
If the FMS takeoff Init had been left at the default flaps 20, and the flaps had inadvertently only been deployed to 10 degrees, the v-speeds would not have "boxed", and there would have been a large yellow "VSPD" caution flag next to the airspeed tape on the pilot's PFD display. Checking that V-speeds are valid is a standard part of the crew's checklist prior to taking the runway, and I doubt that it could have been missed.
In other words, if they indeed started the takeoff roll with flaps 10, I have to think that it was their specific intention to use flaps 10, or they would have noticed the missing V-Speeds before ever advancing the power levers.
There is also a separate takeoff config alarm system, which is operated by microswitches which is activated when the power levers are advanced beyond a certain point. This will give a triple-chime master warning tone and light, as well as a red CAS message if the power levers are advanced and the flaps position sensors detect that the flaps are either less than 10, or greater than 20 degrees.
Now, I HAVE seen this system fail. I don't know if GIV crews routinely test the takeoff config system as part of their preflight cockpit flows, but there is a maintenance requirement to do a functional test of the system every 12 months. We had an early-model (1989) GIV, and when I performed the test in the hangar when it came due, lo and behold, there were no warnings, even with both PLs fully advanced, and the flaps fully up.
It turned out that the microswitches on both the left and right power lever sectors had failed - probably due to age. I remember it particularly well, as accessing and changing the switches was an absolute b***h of a job, due to their location.
I would not want to speculate as to what might have happened in this accident, other than the obvious fact the aircraft departed the end if the runway at high speed without becoming airborne. I do hope that the CVR and FDR will have recoverable data, that will shed light on what may have happened, as this kind of tragedy is shocking to all of us who maintain and fly the GIV.
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JRBarrett
thanks for the great info
do you know if there is a control lock that might not have been disengaged?
wondering also if ther emight have been a major airspeed indicator failure
(mind you, we are taught to rotate regardless of airspeed in the last 1ooo' of runway in certain circumstances)
thanks for the great info
do you know if there is a control lock that might not have been disengaged?
wondering also if ther emight have been a major airspeed indicator failure
(mind you, we are taught to rotate regardless of airspeed in the last 1ooo' of runway in certain circumstances)
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In an earlier post I had hypothesized that this was not an overrun accident, but the presence of tire skid marks running through and off the end of the 1,000ft overrun area would seem to indicate it is just that. What is still baffling to me is that if this is an aborted take-off overrun, why did they not deploy their thrust reversers?
I can only say that from having to perform a near V1 abort myself (due to multiple bird strikes) I was practically bending the T/R levers backwards along with pressing the brake pedals to the firewall when I saw the end of the runway coming up.
The setting of Flaps 10 is equally puzzling to me from this airport, all Gulfstream jets use Flaps 20 as an almost default take-off setting except when taking off from high density altitude airports with long runways, where second segment OEI climb gradient becomes a greater performance limititation than BFL.
That being said, I am aware of some crews preferring to use Flaps 10 as well as a minimum "Flex" (reduced power setting) in order to give their passengers a smoother take-off and less steep initial climb out angle. If this was the case it would likely increase the BFL from well under 4,000ft (Flaps 20, min EPR) by about an additional 2,000ft to just under 6,000ft, but still not enough to explain on overrun of 2,000ft beyond a 7,011 ft runway.
I can only say that from having to perform a near V1 abort myself (due to multiple bird strikes) I was practically bending the T/R levers backwards along with pressing the brake pedals to the firewall when I saw the end of the runway coming up.
The setting of Flaps 10 is equally puzzling to me from this airport, all Gulfstream jets use Flaps 20 as an almost default take-off setting except when taking off from high density altitude airports with long runways, where second segment OEI climb gradient becomes a greater performance limititation than BFL.
That being said, I am aware of some crews preferring to use Flaps 10 as well as a minimum "Flex" (reduced power setting) in order to give their passengers a smoother take-off and less steep initial climb out angle. If this was the case it would likely increase the BFL from well under 4,000ft (Flaps 20, min EPR) by about an additional 2,000ft to just under 6,000ft, but still not enough to explain on overrun of 2,000ft beyond a 7,011 ft runway.
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I haven't seen the pictures, so sorry.
Am I to understand the thrust reversers were NOT deployed?
I speculated earlier, referring to an aborted takeoff with a lear, in which due to mx malfunction, the plane, "THOUGHT" it was in the air and could not use reversers or max wheel braking.
any ideas of similar wow/squat switch logic here?
also wondering on condition of tires, could nose wheel have blown and sucked into eng?
Am I to understand the thrust reversers were NOT deployed?
I speculated earlier, referring to an aborted takeoff with a lear, in which due to mx malfunction, the plane, "THOUGHT" it was in the air and could not use reversers or max wheel braking.
any ideas of similar wow/squat switch logic here?
also wondering on condition of tires, could nose wheel have blown and sucked into eng?