Air North Brasilia Crash in Darwin (Merged)
Sheppey what you say about a good split between V1 and Vr is sound advice if the runway is close to limiting for the weight i.e. accelerate-stop is critical. But at LIGHT weights - as in training or short-haul operations (which are more often landing-weight limited at destination) - there will usually be plenty of margin to allow V1 max for the runway to be scheduled, bearing in mind that it will accelerate very quickly and also stop more quickly because the weight is less than limiting for the runway length. Hence in distance terms, V1 even at 'max' will be reached much earlier than it would be at limiting weight, leaving proportionally more room to stop if need be.
I like the Lufthansa idea of dropping the term V1 in favour of the word 'go'.
One operator I worked with called V1 when 4 knots below actual V1, which also reinforced the idea that by V1 you had to continue.
I like the Lufthansa idea of dropping the term V1 in favour of the word 'go'.
One operator I worked with called V1 when 4 knots below actual V1, which also reinforced the idea that by V1 you had to continue.
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The whole "disengage" quote from the CVR is extremely confusing.
Engaging yaw damper or autopilot has never been a practice at Airnorth, and no-one has even contemplated it - no idea which other companies the CASA interviewed sim instructor was recalling when he stated that some pilots do it as it had nothing to do with Airnorth! We have no clue as to what the pilots involved were refering to or why.
The over-torque to 124% is also puzzling as there has always been a paranoia at Airnorth over even approaching the 20-second 110% torque limit. We also find it unexplainable how a boost up to 124% would be made for so many seconds, and without even a reflexive comment on spotting it and retarding the lever back to within limits.
The physics of the crash sequence are simple enough, but there are too many questions about what was actually happening, and why.
Engaging yaw damper or autopilot has never been a practice at Airnorth, and no-one has even contemplated it - no idea which other companies the CASA interviewed sim instructor was recalling when he stated that some pilots do it as it had nothing to do with Airnorth! We have no clue as to what the pilots involved were refering to or why.
The over-torque to 124% is also puzzling as there has always been a paranoia at Airnorth over even approaching the 20-second 110% torque limit. We also find it unexplainable how a boost up to 124% would be made for so many seconds, and without even a reflexive comment on spotting it and retarding the lever back to within limits.
The physics of the crash sequence are simple enough, but there are too many questions about what was actually happening, and why.
Flautist I believe your response further highlights the deficiencies in the investigation and the final report.
Other than the assumption by the ATSB investigator:
Quote:
The repeated command to ‘disengage’ suggested that the PIC was referring to a system under the control of the pilot under check, most likely the yaw damper.
Nowhere do they actually prove that the Yaw Damper was actuated and then 'disengaged'. It is also unstated about the obvious implications of having the Yaw Damper engaged, contrary to the AFOM.
If anyone has ever inadvertently taken off with a Yaw Damper engaged, while maybe conducting a touch and go, will recall that the feedback/signals felt through the rudder pedals can be very confusing and leads the pilot to make exaggerated inputs. Could this be why the FDR recordings show a series of mixed rudder inputs throughout the recorded data...dare I say questions that again should have been addressed!!??
Flautist as you seem to be 'in the know' with regard to Airnorth, do you know if the Airnorth Brasilias were all fitted with Electonic Trend monitor systems? If so it would be interesting to find out if the YD activation was a recorded parameter! Maybe the ECTM (if it had one) was totally destroyed or maybe not??
The question of why a Checkie would seemingly change his operational checking methods and standards so drastically over a relatively short time frame is very strange.
Prior to this accident Airnorth had reportedly operated the Braz with an exemplary record for a number of years, with a highly regarded T&C department setting a high standard for all its line pilots.
Which makes the actions/inactions of both of these well experienced drivers all the more bizarre, may they RIP!!
Other than the assumption by the ATSB investigator:
Quote:
The repeated command to ‘disengage’ suggested that the PIC was referring to a system under the control of the pilot under check, most likely the yaw damper.
Nowhere do they actually prove that the Yaw Damper was actuated and then 'disengaged'. It is also unstated about the obvious implications of having the Yaw Damper engaged, contrary to the AFOM.
If anyone has ever inadvertently taken off with a Yaw Damper engaged, while maybe conducting a touch and go, will recall that the feedback/signals felt through the rudder pedals can be very confusing and leads the pilot to make exaggerated inputs. Could this be why the FDR recordings show a series of mixed rudder inputs throughout the recorded data...dare I say questions that again should have been addressed!!??
Flautist as you seem to be 'in the know' with regard to Airnorth, do you know if the Airnorth Brasilias were all fitted with Electonic Trend monitor systems? If so it would be interesting to find out if the YD activation was a recorded parameter! Maybe the ECTM (if it had one) was totally destroyed or maybe not??
The question of why a Checkie would seemingly change his operational checking methods and standards so drastically over a relatively short time frame is very strange.
Prior to this accident Airnorth had reportedly operated the Braz with an exemplary record for a number of years, with a highly regarded T&C department setting a high standard for all its line pilots.
Which makes the actions/inactions of both of these well experienced drivers all the more bizarre, may they RIP!!
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Tend to agree that the standard of reports coming out of the ASTB is getting worse.
The PPRUNE thread devoted to that report is here:
http://www.pprune.org/dg-p-reporting...sb-report.html
Is there a really good reference suce on Vmca and bank angle? Ive recently had a look through various instructors notes on Vmca and none mention about increasing Vmce with bank away from the failed engine.
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none mention about increasing Vmce with bank away from the failed engine.
Plenty of reputable references around.
You might try the FAA Handbook for starters at page 12-29.
If one graphs the Vmc variation with bank angle it is shallow near wings level and then increases rapidly with increasing favourable bank (Vmc decreasing) and, likewise, with increasing unfavourable bank (Vmc increasing).
A simple consideration of why bank affects Vmc will demonstrate the general effect of Vmc with bank .. either way.
Plenty of reputable references around.
You might try the FAA Handbook for starters at page 12-29.
If one graphs the Vmc variation with bank angle it is shallow near wings level and then increases rapidly with increasing favourable bank (Vmc decreasing) and, likewise, with increasing unfavourable bank (Vmc increasing).
A simple consideration of why bank affects Vmc will demonstrate the general effect of Vmc with bank .. either way.
