Challenger beyond repair after in-flight upset?
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RAT deployment is gravity/airflow only so may well have been compromised (think a non-deployment of a CRJ ADG happened once during testing in about 20 years but it hadn't been stowed correctly - unlike normal operations the ADG was routinely dropped for access). AFAIK the APU will start & run over the entire envelope but just can't be guaranteed. Again from testing, you get some residual Hydraulics from the Reservoirs (my memory is up to about 40s but, as I said, the more you use the controls, the quicker the pressure dissipates).
On the CRJ you would retain some roll control via the Spoilerons, which are electrically operated & at least one channel on Battery, but it's been many years since I worked on Challengers and I'm not sure what the latest CL604/605 version has.
On the CRJ you would retain some roll control via the Spoilerons, which are electrically operated & at least one channel on Battery, but it's been many years since I worked on Challengers and I'm not sure what the latest CL604/605 version has.
Our 605s have ADG pins to prevent inadvertent deployment on the ground - if not removed they would also prevent manual or automatic deployment in flight.
Not saying this is what happened here - but it is an outside possibility .... its happened numerous times with gear pins
Not saying this is what happened here - but it is an outside possibility .... its happened numerous times with gear pins
@ ICT SLB...
Like I said in my post anything is possible about the APU just no guarantees. Also the APU system on the RJ is not identical to the CL64.
Although later versions of the 604 came with the same APU as the original RJs, it could not be used at high altitude like the RJ… You cannot load it up with pneumatic/bleed and electrical power at the same time while in flight. Bleed extraction must not be used above 15,500 feet. The 604's APU does not have a retractable door like the RJ but a small fixed scoop. All small differences I’m sure but perhaps that’s why Bombardier never changed the AFM’s restrictions even after the new APU was installed.
Like I said the RAT should deploy automatically (squib releases the lock and out it goes) or manually by physically pulling on a cable that releases that same lock and yes gravity/airflow takes care of the rest. As to why it did not release in this case, well you mentioned a possibility and another possible reason is perhaps the severe G force encountered during the event that would have prevented its release.
As Globally Challenged said the RAT locking pin could have been left in placed, now that would be embarrassing.
On the hydraulics, yes there is a possibility of residual hydraulic for a very limited time but again I have to doubt about it being available through 3 or 5 rolls and a descent of 10,000 feet and this to me is the portion of this incident I’m really interested in… Time will tell.
There are no spoilerons on any Challengers (600/601/604/605/650).
Like I said in my post anything is possible about the APU just no guarantees. Also the APU system on the RJ is not identical to the CL64.
Although later versions of the 604 came with the same APU as the original RJs, it could not be used at high altitude like the RJ… You cannot load it up with pneumatic/bleed and electrical power at the same time while in flight. Bleed extraction must not be used above 15,500 feet. The 604's APU does not have a retractable door like the RJ but a small fixed scoop. All small differences I’m sure but perhaps that’s why Bombardier never changed the AFM’s restrictions even after the new APU was installed.
Like I said the RAT should deploy automatically (squib releases the lock and out it goes) or manually by physically pulling on a cable that releases that same lock and yes gravity/airflow takes care of the rest. As to why it did not release in this case, well you mentioned a possibility and another possible reason is perhaps the severe G force encountered during the event that would have prevented its release.
As Globally Challenged said the RAT locking pin could have been left in placed, now that would be embarrassing.
On the hydraulics, yes there is a possibility of residual hydraulic for a very limited time but again I have to doubt about it being available through 3 or 5 rolls and a descent of 10,000 feet and this to me is the portion of this incident I’m really interested in… Time will tell.
There are no spoilerons on any Challengers (600/601/604/605/650).
Last edited by Jet Jockey A4; 11th Mar 2017 at 13:50.
Agree on all of the above.
However:
The 300 has multi-function spoilers which include roll-control (I presume the 350 does too as I think it was only minor changes from the 300)
However:
There are no spoilerons on any Challengers.
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There was a column in the US "Flying" magazine a few years ago written by a B777 captain on a transatlantic flight who wrote about the turbulence he encountered from an A380 a few miles ahead and a thousand feet above. In that case it was after their tracks had crossed. I recall the writer was very surprised at the level of turbulence caused at the time.
About the first month of NAT RVSM in '97, I, in a loaded C-5, was approaching landfall in Gander airspace, when an opposite direction B747 (FDX, IIRC) passed a 1,000' above. A minute later, after a brief discussion along the lines of "what's this gonna be like" we hit the wake--rolled 30-40 degrees, autopilot said, "I can't do this, about you guys try it". Ever since, especially flying bizjets, even large ones, I've been cautious around heavies
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No real new info, but another article on Flight Service Bureau:
Enroute A380 wake flips Challenger 604 upside down
Enroute A380 wake flips Challenger 604 upside down
Last edited by slfool; 17th Mar 2017 at 09:51. Reason: formatting
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Bombardier issued the following Advisory wire this afternoon concerning this incident...
"This Advisory Wire (AW) is to provide clarification on recent media reporting of a temporary loss of control
event which occurred on a Challenger 604 on January 7th, 2017.
DESCRIPTION:
It was reported to Bombardier that a Challenger 604 was flying over the Arabian Sea at 34,000 feet when it
experienced a temporary loss of control which resulted in significant loss of altitude, abnormal flight attitudes,
and accelerations beyond the certificated flight envelope.
Shortly after the event, the crew shut down one engine due to a high ITT (Inter Turbine Temperature)
indication; the other engine remained operational. The crew eventually regained control of the aircraft, later on
relit the engine which had been shut down, diverted from their intended destination and landed safely without
further incident. There were serious injuries to some passengers on-board. The flight crew reported that shortly
before the event an oncoming large transport category aircraft passed them with 1,000 feet clearance above,
and slightly offset to the left.
The German Federal Bureau of Aircraft Accident Investigation (BFU), representing the State of Registry of the
Challenger 604 involved in this event, has classified the event as an Accident and initiated an investigation
pursuant to ICAO Annex 13 protocols. The Transportation Safety Board of Canada (TSB), representing the
State of Design and Manufacture of the Challenger 604 has been appointed as an Accredited Representative
to the investigation. Bombardier has been appointed as a Technical Advisor to the TSB for the purposes of this
investigation.
Note that Bombardier cannot provide further comment on the investigation beyond what has been stated in this
AW. The BFU, as the investigating agency, will communicate investigation progress as and when it deems fit."
3.
"This Advisory Wire (AW) is to provide clarification on recent media reporting of a temporary loss of control
event which occurred on a Challenger 604 on January 7th, 2017.
DESCRIPTION:
It was reported to Bombardier that a Challenger 604 was flying over the Arabian Sea at 34,000 feet when it
experienced a temporary loss of control which resulted in significant loss of altitude, abnormal flight attitudes,
and accelerations beyond the certificated flight envelope.
Shortly after the event, the crew shut down one engine due to a high ITT (Inter Turbine Temperature)
indication; the other engine remained operational. The crew eventually regained control of the aircraft, later on
relit the engine which had been shut down, diverted from their intended destination and landed safely without
further incident. There were serious injuries to some passengers on-board. The flight crew reported that shortly
before the event an oncoming large transport category aircraft passed them with 1,000 feet clearance above,
and slightly offset to the left.
The German Federal Bureau of Aircraft Accident Investigation (BFU), representing the State of Registry of the
Challenger 604 involved in this event, has classified the event as an Accident and initiated an investigation
pursuant to ICAO Annex 13 protocols. The Transportation Safety Board of Canada (TSB), representing the
State of Design and Manufacture of the Challenger 604 has been appointed as an Accredited Representative
to the investigation. Bombardier has been appointed as a Technical Advisor to the TSB for the purposes of this
investigation.
Note that Bombardier cannot provide further comment on the investigation beyond what has been stated in this
AW. The BFU, as the investigating agency, will communicate investigation progress as and when it deems fit."
3.
This makes more sense... No RAT deployment because the crew shut down one engine and the other remained operational... Also explains why they could recover from their unusual attitudes because they still had hydraulic power.
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It would be a boring picture anyway. There are no signs of any damage. Very up close there might be indications of overstress, but from 20 meters there is nothing obvious.
Do we know beyond doubt this was wake turbulence? I ask as a retired meteorologist who made a study of CAT of all sorts. If such incidents can with certainty be attributed to wake, then procedures could be evolved. If, however, random CAT from Kelvin-Helmholtz events, much more difficult to deal with.
So, do we know, or is wake a handy villain to blame?
So, do we know, or is wake a handy villain to blame?
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While wake will descend, depending on conditions, they really only go about 500 feet. There are many images and video that show A380 and other wake, and most of the time, the energy is in the rotation, and sink is a function of the weight and associated pressure.
In regards to KH waves...isnt that more washboard that roll?
Given what what was reported, vs the actual from the manufacturer, it is difficult to believe much at this point.
In regards to KH waves...isnt that more washboard that roll?
Given what what was reported, vs the actual from the manufacturer, it is difficult to believe much at this point.
Hmm why would they actually shut down an engine? I can cutting thrust as a response to the overheat warning but would engine shutdown be a SOP in such circumstances?
@langleybaston surely a singular vortex would be an unlikely scenario, given the characteristic turbidity of boundary condition flow? And a vortex strong enough to lead to uncontrolled bank excursion would have to be extremely violent and tight, never heard about anything of that magnitude being generated by turbulent flow alone.
@ atakacs...
The Challenger 604's checklist call for the engine to be retarded until the message (ITT in red) goes out, if it doesn't then a shutdown is required.
The Challenger 604's checklist call for the engine to be retarded until the message (ITT in red) goes out, if it doesn't then a shutdown is required.