HAA crash all survived 11th Jan 2022
The other UK one.
https://www.gov.uk/aaib-reports/euro...-february-2002
The following is a fatal accident in the USA after a likely SAS cut following loss of SA.
https://www.accidents.app/summaries/...20170525X33813
I do however struggle to see how SAS CUT in good VMC could reach the point of barrel rolling the aircraft. And I have seen some very spirited attempts to mis-handle the aircraft!
https://www.gov.uk/aaib-reports/euro...-february-2002
The following is a fatal accident in the USA after a likely SAS cut following loss of SA.
https://www.accidents.app/summaries/...20170525X33813
I do however struggle to see how SAS CUT in good VMC could reach the point of barrel rolling the aircraft. And I have seen some very spirited attempts to mis-handle the aircraft!
Well that's exactly what it was (https://aerossurance.com/helicopters...ne-overspeeds/). That makes by my reckoning five accidents on EC135 due to inadvertent pressing of the SAS DCPL button in flight and then loss of control. (G-IWRC, G-SPAU, YR-CPC, N62UP). Interestingly with an AFCS fitted, only one emergency (AHRS failure followed by second AHRS fail) actually involves touching that switch at all. All the others are only applicable to non AFCS aircraft (although this is not highlighted in the Airbus FRC). Ironic that a switch that is only used in a very improbable emergency should be a major cause of 5.
Definitely an emergency that needs training (preferably in a sim!)
Who has not made that mistake in aircraft that had a manual heading bug or one that did as described in the Report?
Night, messy weather, a couple of IIMC events, rising terrain about, single pilot, no NVG's, and one can see how a fellow can get overloaded.
Good thing all survived what could have easily been a very bad outcome.
The Pilot should not feel too badly....as in my opinion he had a lot of help getting into that situation.
The Report spent a lot of time on the technical issues and in time hopefully it will delve into the collateral issues re training, standard operating procedures, and minimal for night ops without NVG.
Use of a fitted AFCS using Upper Modes (at the minimum of heading hold, altitude hold) at night at all times other maneuvering to land in clear visual contact with the surface via either celestial or ground based lighting or both with the landing spot/runway in view.
Years ago we had a very good discussion about just that during approaches to offshore landing sites.
It was seen to provide an improvement in the visual approaches to Rigs and Platforms at night and that was in aircraft with two Pilots.
One of our frequent posters here was directly involved in that effort and gained credit for that concept.
You might take a look back at the Kobe Bryant crash near Los Angeles that figured in a long thread here that involved a fully kitted out S-76 that was crashed into terrain following a loss of control by the Pilot flying it Single Pilot.
During an IIMC event at night is not the best of times to try to figure out why the AFCS is not working as you think it should and perhaps a natural instinct would be to manually disconnect what you think is a failed AFCS and. try to hand fly the machine.
Years of teaching in Simulators I have seen exactly that when all that was going on was the HDG Bug had not been rotated to somewhat very near the current Heading of the aircraft when the Pilot elected to engage the Heading Hold function.
In todays magic flying machines perhaps the Authorities should require the AFCS to automatically slew to the current heading....and thus prevent this from happening.
That would change the protocol to requiring the Pilot to manually choose a different Heading than the aircraft is on if a heading change is desired.
Or am I all wrong in thinking that way?
Night, messy weather, a couple of IIMC events, rising terrain about, single pilot, no NVG's, and one can see how a fellow can get overloaded.
Good thing all survived what could have easily been a very bad outcome.
The Pilot should not feel too badly....as in my opinion he had a lot of help getting into that situation.
The Report spent a lot of time on the technical issues and in time hopefully it will delve into the collateral issues re training, standard operating procedures, and minimal for night ops without NVG.
Use of a fitted AFCS using Upper Modes (at the minimum of heading hold, altitude hold) at night at all times other maneuvering to land in clear visual contact with the surface via either celestial or ground based lighting or both with the landing spot/runway in view.
Years ago we had a very good discussion about just that during approaches to offshore landing sites.
It was seen to provide an improvement in the visual approaches to Rigs and Platforms at night and that was in aircraft with two Pilots.
One of our frequent posters here was directly involved in that effort and gained credit for that concept.
You might take a look back at the Kobe Bryant crash near Los Angeles that figured in a long thread here that involved a fully kitted out S-76 that was crashed into terrain following a loss of control by the Pilot flying it Single Pilot.
During an IIMC event at night is not the best of times to try to figure out why the AFCS is not working as you think it should and perhaps a natural instinct would be to manually disconnect what you think is a failed AFCS and. try to hand fly the machine.
Years of teaching in Simulators I have seen exactly that when all that was going on was the HDG Bug had not been rotated to somewhat very near the current Heading of the aircraft when the Pilot elected to engage the Heading Hold function.
In todays magic flying machines perhaps the Authorities should require the AFCS to automatically slew to the current heading....and thus prevent this from happening.
That would change the protocol to requiring the Pilot to manually choose a different Heading than the aircraft is on if a heading change is desired.
Or am I all wrong in thinking that way?
SAS, it was day CAVOK. Look at the link in the Aerossurance report and see the doorbell video that has the rotor signature - totally gin clear.
212Man,
My remarks refer to the G-SPAU police air services crash report that was linked.
2215 hrs in Scotland in the Winter with multiple IIMC events in one flight.
https://assets.publishing.service.go...pdf_023427.pdf
My remarks refer to the G-SPAU police air services crash report that was linked.
2215 hrs in Scotland in the Winter with multiple IIMC events in one flight.
https://assets.publishing.service.go...pdf_023427.pdf
212Man,
My remarks refer to the G-SPAU police air services crash report that was linked.
2215 hrs in Scotland in the Winter with multiple IIMC events in one flight.
https://assets.publishing.service.go...pdf_023427.pdf
My remarks refer to the G-SPAU police air services crash report that was linked.
2215 hrs in Scotland in the Winter with multiple IIMC events in one flight.
https://assets.publishing.service.go...pdf_023427.pdf
Perhaps there might are a separate thread to discuss the certification and engineering design concepts re modern digital avionics and fly by wire systems integration into new build helicopters.
Some of the comments in the existing Hill Helicopter program begin to go there but focused directly upon that one program.
Training and systems knowledge questions are arising in many accident reports as well.
Then....there is the Kids of the Magenta Line thing or whatever that is known by....which talks about automation and some of its pitfalls.
In your past work experience I am sure you have seen some "transition" difficulties by those first becoming introduced to such new and interesting systems.
Some of the comments in the existing Hill Helicopter program begin to go there but focused directly upon that one program.
Training and systems knowledge questions are arising in many accident reports as well.
Then....there is the Kids of the Magenta Line thing or whatever that is known by....which talks about automation and some of its pitfalls.
In your past work experience I am sure you have seen some "transition" difficulties by those first becoming introduced to such new and interesting systems.
Perhaps there might are a separate thread to discuss the certification and engineering design concepts re modern digital avionics and fly by wire systems integration into new build helicopters.
Some of the comments in the existing Hill Helicopter program begin to go there but focused directly upon that one program.
Training and systems knowledge questions are arising in many accident reports as well.
Then....there is the Kids of the Magenta Line thing or whatever that is known by....which talks about automation and some of its pitfalls.
In your past work experience I am sure you have seen some "transition" difficulties by those first becoming introduced to such new and interesting systems.
Some of the comments in the existing Hill Helicopter program begin to go there but focused directly upon that one program.
Training and systems knowledge questions are arising in many accident reports as well.
Then....there is the Kids of the Magenta Line thing or whatever that is known by....which talks about automation and some of its pitfalls.
In your past work experience I am sure you have seen some "transition" difficulties by those first becoming introduced to such new and interesting systems.
You can substitute the dog analogy to "culture" if needed.
"What's it doing now?" is not unique to helicopters.
Thread Starter
Flight track data from the helicopter air ambulance flight indicated that, while in cruise flight at an altitude of about 1,500 ft mean sea level (msl), the helicopter departed normal cruise flight with an abrupt increase in altitude, followed by a dive. The recovered data from various sources onboard the helicopter did not contain information as to whether the helicopter rolled inverted during this altitude excursion, as recalled by the crewmembers. Surveillance video showed the helicopter in a near-vertical, nose-down, spiraling descent. The pilot arrested the rotation and recovered the helicopter from the dive but was unable to climb or hover due to insufficient engine power, thereby resulting in a hard landing to a city street and substantial damage to the helicopter. Examination of the helicopter revealed no evidence of malfunction that would result in an abrupt departure from cruise flight.
Because of the limited control authority of the Stability Augmentation System (SAS) actuators, it is unlikely that a malfunction of a SAS actuator would have resulted in an inflight upset before the pilot could react to the malfunction. Additionally, a malfunction of a trim actuator would not result in an inflight upset as the pilot would notice an attitude deviation before the trim actuator, whose rate of movement is limited by design, would be able to move the helicopter into an unusual attitude.
Data indicated that a main rotor system overspeed, which likely occurred during the dive maneuver, resulted in the overspeed of both engine power turbines due to the sudden reduction in load from the main rotor. As a result of the power turbine overspeed, both engine control systems, independent of each other, functioned as designed and reverted to manual mode while at a minimum fuel flow rate. Both engines continued to run at low power without automatic governing, resulting in insufficient power to continue normal flight as the engine twist grips remained in the normal fly position for the duration of the flight.
N531LN EUROCOPTER DEUTSCHLAND GMBH EC135 P2+
Findings
Aircraft Powerplant parameters - Capability exceeded
Personnel issues Aircraft control - Unknown/Not determined
Not determined (general) - Unknown/Not determined
Aircraft Main rotor mast/swashplate - Capability exceeded
Probable Cause
An inflight attitude upset for undetermined reasons that resulted in a rotor system overspeed, a reduction of power from both engines, and a subsequent hard landing.
Because of the limited control authority of the Stability Augmentation System (SAS) actuators, it is unlikely that a malfunction of a SAS actuator would have resulted in an inflight upset before the pilot could react to the malfunction. Additionally, a malfunction of a trim actuator would not result in an inflight upset as the pilot would notice an attitude deviation before the trim actuator, whose rate of movement is limited by design, would be able to move the helicopter into an unusual attitude.
Data indicated that a main rotor system overspeed, which likely occurred during the dive maneuver, resulted in the overspeed of both engine power turbines due to the sudden reduction in load from the main rotor. As a result of the power turbine overspeed, both engine control systems, independent of each other, functioned as designed and reverted to manual mode while at a minimum fuel flow rate. Both engines continued to run at low power without automatic governing, resulting in insufficient power to continue normal flight as the engine twist grips remained in the normal fly position for the duration of the flight.
N531LN EUROCOPTER DEUTSCHLAND GMBH EC135 P2+
Findings
Aircraft Powerplant parameters - Capability exceeded
Personnel issues Aircraft control - Unknown/Not determined
Not determined (general) - Unknown/Not determined
Aircraft Main rotor mast/swashplate - Capability exceeded
Probable Cause
An inflight attitude upset for undetermined reasons that resulted in a rotor system overspeed, a reduction of power from both engines, and a subsequent hard landing.
