VH-PGW ATSB report
Puff
I think I found the Baron incident that you refer to. it's report 200000624. Unfortunately the ATSB do not publish the full report - only the synopsis.
In that case he had a dead engine, pure & simple and I think the simply "dead leg, dead engine, confirm with throttle" routine would have identified that.
In this case the engine was unquestionably delivering power. The engine was surging and probable the aircraft was yawing in response to the surges. As the engine surged it would have gone out of sync, so there would have been constantly changing beating as well. The question no one will be able to answer is whether there was a low power setting that would have stabilised the engine and delivered more power than the zero thrust setting.
In the early stages of the incident (before the RH engine was feathered) the desecnt rate was up to 1600 fpm without any corresponding speed increase. This suggests that the desecnt rate was caused by the drag of the mis behaving RH engine / yawing aircraft rather than poor airspeed / attitude control by the pilot.
I think shutting down the RH engine was a good decision. Whether or not it was the perfect decision can be debated for some time. Its interesting to note that my Seneca II POH does not have any reference to action for a mis behaving CSU. This would make me wonder if the Mojave POH is similarly deficient. Another thing the ATSB might have considered but did not.
I think I found the Baron incident that you refer to. it's report 200000624. Unfortunately the ATSB do not publish the full report - only the synopsis.
In that case he had a dead engine, pure & simple and I think the simply "dead leg, dead engine, confirm with throttle" routine would have identified that.
In this case the engine was unquestionably delivering power. The engine was surging and probable the aircraft was yawing in response to the surges. As the engine surged it would have gone out of sync, so there would have been constantly changing beating as well. The question no one will be able to answer is whether there was a low power setting that would have stabilised the engine and delivered more power than the zero thrust setting.
In the early stages of the incident (before the RH engine was feathered) the desecnt rate was up to 1600 fpm without any corresponding speed increase. This suggests that the desecnt rate was caused by the drag of the mis behaving RH engine / yawing aircraft rather than poor airspeed / attitude control by the pilot.
I think shutting down the RH engine was a good decision. Whether or not it was the perfect decision can be debated for some time. Its interesting to note that my Seneca II POH does not have any reference to action for a mis behaving CSU. This would make me wonder if the Mojave POH is similarly deficient. Another thing the ATSB might have considered but did not.
In the early stages of the incident (before the RH engine was feathered) the desecnt rate was up to 1600 fpm without any corresponding speed increase. This suggests that the desecnt rate was caused by the drag of the mis behaving RH engine / yawing aircraft rather than poor airspeed / attitude control by the pilot.
Sorry, but I find that hard to believe.
Dr
PS: Yes, I am endorsed on the PA31.
Mojo POH emerg actions for engine failure during climb...
1.airspeed 101kts
2.directional control, maintain
3.power op engine, max continuous
4.inop engine, identify and verify
5.inop engine, complete engine securing procedure.
Land as soon as possible at nearest suitable airport.
Actions for engine roughness...
1.emerg fuel pumps on
2.engine instruments, scan for cause
3.mixture, adjust as required
4.alternate air, on
5.cowl flaps, adjust for proper CHT
6.magnetos, check
He appears to have actioned as per the POH for failure in climb. Just possibly not the correct airspeed and descended. Might have also been a different story if he didnt have 900 (650kg) odd litres of fuel on board.
They are an awsome ifr aircraft to fly normal ops, but Im not confident they will not maintain height at mtow 1 inop. They feel and perform a little differently to the chieftain.
1.airspeed 101kts
2.directional control, maintain
3.power op engine, max continuous
4.inop engine, identify and verify
5.inop engine, complete engine securing procedure.
Land as soon as possible at nearest suitable airport.
Actions for engine roughness...
1.emerg fuel pumps on
2.engine instruments, scan for cause
3.mixture, adjust as required
4.alternate air, on
5.cowl flaps, adjust for proper CHT
6.magnetos, check
He appears to have actioned as per the POH for failure in climb. Just possibly not the correct airspeed and descended. Might have also been a different story if he didnt have 900 (650kg) odd litres of fuel on board.
They are an awsome ifr aircraft to fly normal ops, but Im not confident they will not maintain height at mtow 1 inop. They feel and perform a little differently to the chieftain.
Ok. What then?
By 0754:35 it was 140 KIAS 900 fpm and gear horn blaring and speed RoD reducing.
In the 1.5 minutes in between these we see transitions up to 160 KIAS and 1600 fpm but not simultaneously.
I got the feeling that these time stamp snap shots were showing the power coming off the surging engine with the trottle being closed (and drag significantly increasing) then feathering occuring and speed increasing and RoD decreasing.
I imagine during this time he had his head down in the cockpit while holding a nose down profile and hand flying.
Who knows where the trim was, and with all that was going on around him coupled with some tasks he was trying to get accomplished it suprises me little that speed and RoD were all over the place for 90 seconds.
Just a shame he didn't get back to Vyse after it was all done.
But hey I wasn't there, we don't know if while all this was going on he didn't spill a hot coffee on his crutch further compounding the issues.
In this day and age surely it must be possible to have a cheap rugged basic data recording device in these things. Certainly would make it easier to garner information later.
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Obidiah, I think you may have made an incorrect assumption when you said 130 KIAS
The report describes the speed as "Derived airspeed: 130 kts"
I think perhaps that the speed was 'derived' from the radar recorded groundspeed and adjusted for the 'wind' at the time.
If that is the case, and the 'derived airspeed' was a TAS of 130 knots, therefore the IAS (@ 7000 feet) would be about 110 knots.
After AW reported shutting down an engine @ 07.53.33 his 'derived airspeed' was 120 knots (@ 6100 feet), that would make his IAS roundabouts 105 knots. (much closer to blue line than some people here seem to think)
If I am incorrect about how the 'derived airspeed' in the report was calculated, then everything I have written above is BS of course.
Increased RoD during the turn back to BWU would most likely have been the cause of the higher descent rate without a consequent speed increase.
edit.
Reading this report makes we weep for the families of the victims.
It seems to me that AW gave it a 'good shot' considering the situation he was in and with the tools he had at hand.
I hope that a lot of the 'younguns' in GA read the report and take away some lessons to enhance their own skills and decision making processes.
The way I read the sequence it was 0753:00 and no gear horn 130 KIAS/1000 fpm some thrust from the surging engine
I think perhaps that the speed was 'derived' from the radar recorded groundspeed and adjusted for the 'wind' at the time.
If that is the case, and the 'derived airspeed' was a TAS of 130 knots, therefore the IAS (@ 7000 feet) would be about 110 knots.
After AW reported shutting down an engine @ 07.53.33 his 'derived airspeed' was 120 knots (@ 6100 feet), that would make his IAS roundabouts 105 knots. (much closer to blue line than some people here seem to think)
If I am incorrect about how the 'derived airspeed' in the report was calculated, then everything I have written above is BS of course.
Increased RoD during the turn back to BWU would most likely have been the cause of the higher descent rate without a consequent speed increase.
edit.
Reading this report makes we weep for the families of the victims.
It seems to me that AW gave it a 'good shot' considering the situation he was in and with the tools he had at hand.
I hope that a lot of the 'younguns' in GA read the report and take away some lessons to enhance their own skills and decision making processes.
Last edited by Trent 972; 23rd Dec 2012 at 13:38.
Trent
Thanks. I think that adds perspective to the debate. I agree that I have sympathy for the families and I'm pretty upset that they didn't get the ATSB report that they deserved.
The pilot of PGW did many things right and he seems a good, reasonable pilot if not a superhero. A lot of the initial conjecture about fuel issues or shutting down the wrong engine have been disproven. In theory, an engine failure around 15nm out from Bankstown should not have had this result. As a light twin pilot I'd like to understand this accident and learn from it. The ATSB report does not help this.
Thanks. I think that adds perspective to the debate. I agree that I have sympathy for the families and I'm pretty upset that they didn't get the ATSB report that they deserved.
The pilot of PGW did many things right and he seems a good, reasonable pilot if not a superhero. A lot of the initial conjecture about fuel issues or shutting down the wrong engine have been disproven. In theory, an engine failure around 15nm out from Bankstown should not have had this result. As a light twin pilot I'd like to understand this accident and learn from it. The ATSB report does not help this.
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atsb and attitude to accidents
Just my two penneth:
I also have had a look at the PA31-350 POH and concur with the data above. I have 1400 hours twin time, with 150 odd in PA31-350's and rest in PA30-160.
In both aircraft, it is essential to do the troubleshooting routine.
It is essential to ID the engine.
I have had two reductions of power and "Panic" is not an option, but it is a real issue.
A decision has to be made quickly and a "blaring" gear horn would not help.
Flying the "numbers" is essential ie. Vyse and 5 degrees bank.
The old adage of height is your friend cannot be understated.
The real issue of "Why the surging" has not been answered by atsb, neither the human factors involved.
I also have had a look at the PA31-350 POH and concur with the data above. I have 1400 hours twin time, with 150 odd in PA31-350's and rest in PA30-160.
In both aircraft, it is essential to do the troubleshooting routine.
It is essential to ID the engine.
I have had two reductions of power and "Panic" is not an option, but it is a real issue.
A decision has to be made quickly and a "blaring" gear horn would not help.
Flying the "numbers" is essential ie. Vyse and 5 degrees bank.
The old adage of height is your friend cannot be understated.
The real issue of "Why the surging" has not been answered by atsb, neither the human factors involved.
The ATSB preliminary report publishes a number of position details. It used groundspeed. The final ATSB published position reports using a "derived airspeed". Out of a combined (approx) 35 data points there are 9 in common between the 2 reports. This reveals that the ATSB have given PGW tailwind components of 7 - 23 knots both climbing away from Bankstown, in the turnaround and on descent back towards Bankstown. Its looking like the ATSB have messed up the whole airspeed element.
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The real issue of "Why the surging" has not been answered.....
More than anything else in this 'report' - I would have expected some in-depth engineering discussion!
".... and the number six nozzle from the right engine was completely blocked."
Well, it takes a solid object to block the size of the 'piss and dribble' nozzle, so what was it? Considering the nozzle is shielded by metal from the fire, it should be possible to analyse the foreign object.
Not done....... which is the crux of the whole event and the ATSB didn't go there.
For an object this large to have got through the fuel pump - WHAT is left in the fuel pump - and hence a blockage to fuel supply to all injectors, causing the surging/overspeed (which a CSU can't capture quickly enough).
No discussion, no examination apart from.......
"The ATSB was unable to determine whether the erratic nozzle spray patterns and blockage of the number six nozzle were due to pre-impact contamination."
The blockage couldn't happen after the engine was feathered, or after the accident.
Five paragraphs only on the Engine and ancillary systems - when this is what caused the sequence of actions which culminated in the accident.
C'mon........
".... and the number six nozzle from the right engine was completely blocked."
Well, it takes a solid object to block the size of the 'piss and dribble' nozzle, so what was it? Considering the nozzle is shielded by metal from the fire, it should be possible to analyse the foreign object.
Not done....... which is the crux of the whole event and the ATSB didn't go there.
For an object this large to have got through the fuel pump - WHAT is left in the fuel pump - and hence a blockage to fuel supply to all injectors, causing the surging/overspeed (which a CSU can't capture quickly enough).
No discussion, no examination apart from.......
"The ATSB was unable to determine whether the erratic nozzle spray patterns and blockage of the number six nozzle were due to pre-impact contamination."
The blockage couldn't happen after the engine was feathered, or after the accident.
Five paragraphs only on the Engine and ancillary systems - when this is what caused the sequence of actions which culminated in the accident.
C'mon........
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Several posters and the 'report', have made reference to the "blaring gear horn".
Recognition of the aural Stall Warning on AF447 was investigated and is the subject of further investigation by EASA.
Quoting from Flightglobal AF447 inquiry grapples with stall-warning enigma
Perhaps the warning horn was not as distracting as some may think, as in the case of AF447, where the crew did not comment on the repetitive "stall stall" warning.
The human brain is an amazing thing.
Recognition of the aural Stall Warning on AF447 was investigated and is the subject of further investigation by EASA.
Quoting from Flightglobal AF447 inquiry grapples with stall-warning enigma
It cites cognitive research suggesting that visual, rather than auditory, information is prioritised by pilots coping with high workloads.
"Piloting, calling heavily on visual activity, could lead pilots to a type of auditory insensitivity to the appearance of aural warnings that are rare and in contradiction with cockpit information," the analysis says
"Piloting, calling heavily on visual activity, could lead pilots to a type of auditory insensitivity to the appearance of aural warnings that are rare and in contradiction with cockpit information," the analysis says
The human brain is an amazing thing.
Trent 972
My apology on KIAS
I assumed it was corrected data for KIAS, TAS seems more likely now you mention it. Would've been handy if the report had made it a little clearer.
Up into the Air
Be careful on the 5 to the live notion as it is somewhat of an OWT.
Detail can be found in the FAR23 certification standards, which is where it was born from. 5 degrees is a certification requirement.
Reality is for low performance twins it is typically less.
John C Eckalber's book "Flying High Performance Singles and Twins" gives detailed explanation on this as well as methods for calculating the optimum angle for each type.
Apparently research has shown that for every degree off optimum the loss is about 30 fpm and the typical light twins zero side slip angle is around 2 degrees.
How we as pilots will ever be able to fly that acurately in a real assymetric scenario baffles me, but there it is. Perhaps as I mentioned earlier we just need more quality time with one feathered.
My apology on KIAS
I assumed it was corrected data for KIAS, TAS seems more likely now you mention it. Would've been handy if the report had made it a little clearer.
Up into the Air
Be careful on the 5 to the live notion as it is somewhat of an OWT.
Detail can be found in the FAR23 certification standards, which is where it was born from. 5 degrees is a certification requirement.
Reality is for low performance twins it is typically less.
John C Eckalber's book "Flying High Performance Singles and Twins" gives detailed explanation on this as well as methods for calculating the optimum angle for each type.
Apparently research has shown that for every degree off optimum the loss is about 30 fpm and the typical light twins zero side slip angle is around 2 degrees.
How we as pilots will ever be able to fly that acurately in a real assymetric scenario baffles me, but there it is. Perhaps as I mentioned earlier we just need more quality time with one feathered.
I assumed it was corrected data for KIAS, TAS seems more likely now you mention it. Would've been handy if the report had made it a little clearer.
1. According to the prelim & final report the Bankstown METAR was 340 deg @ 4 kts and the METAR for Richmond was calm. However at the final fix 6nm from YSBK at 500 ft they are using an 11 knot tailwind component.
2. No met data for winds aloft has been tabled. The Prelim report quotes speed as Groundspeed derived from TXP returns. There are not many data points that correlate between the 2 reports, but there are 9. Just before TOC over Richmond flying pretty much North, the ATSB calculations show a 19 kt tailwind. 4 minutes later having turned through slightly more than 180 degrees at the same altitude (after having climbed further, then descended) they are using a 16 kt tailwind. How does this work?
I don't think any of the "derived airspeeds"can be relied upon at all. Which completely undermines their conclusion that the pilot was not managing airspeed.
This is a seriously flawed report
Last edited by Old Akro; 23rd Dec 2012 at 10:26. Reason: spelling
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Obid said
Indeed, and John Deakin makes special mention of that point, and in subsequent emails we have had. It may well be the extra ROD is attributable to these things. Again ATSB have not exactly explored this either, as an educational piece for others to learn from in the future.
The report is a disgrace.
Just like MZK, more recently the Norfolk dip. Why are we wasting taxpayers money on reports if they are not yielding any safety benefit.
When I started this thread I hoped for better than this. To say it is underwhelming is an understatement.
I doubt there is anyone there who really understands a piston engine, let alone how to fly a piston twin. The biggest insult is I believe I could have done a far better job. That is seriously sad.
A sad way to end 2012.
Be careful on the 5 to the live notion as it is somewhat of an OWT.
Detail can be found in the FAR23 certification standards, which is where it was born from. 5 degrees is a certification requirement.
Reality is for low performance twins it is typically less.
John C Eckalber's book "Flying High Performance Singles and Twins" gives detailed explanation on this as well as methods for calculating the optimum angle for each type.
Apparently research has shown that for every degree off optimum the loss is about 30 fpm and the typical light twins zero side slip angle is around 2 degrees.
How we as pilots will ever be able to fly that acurately in a real assymetric scenario baffles me, but there it is. Perhaps as I mentioned earlier we just need more quality time with one feathered.
Detail can be found in the FAR23 certification standards, which is where it was born from. 5 degrees is a certification requirement.
Reality is for low performance twins it is typically less.
John C Eckalber's book "Flying High Performance Singles and Twins" gives detailed explanation on this as well as methods for calculating the optimum angle for each type.
Apparently research has shown that for every degree off optimum the loss is about 30 fpm and the typical light twins zero side slip angle is around 2 degrees.
How we as pilots will ever be able to fly that acurately in a real assymetric scenario baffles me, but there it is. Perhaps as I mentioned earlier we just need more quality time with one feathered.
The report is a disgrace.
Just like MZK, more recently the Norfolk dip. Why are we wasting taxpayers money on reports if they are not yielding any safety benefit.
When I started this thread I hoped for better than this. To say it is underwhelming is an understatement.
I doubt there is anyone there who really understands a piston engine, let alone how to fly a piston twin. The biggest insult is I believe I could have done a far better job. That is seriously sad.
A sad way to end 2012.
Last edited by Jabawocky; 23rd Dec 2012 at 11:01.
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Hi Jaba. Merry Christmas to you and yours. 
I'm only a mug playing a guessing game, but I assume the RoD came from the Mode C radar data and is independent of the airspeed.
My understanding is that the altitude readout is given in increments of 100 feet on a controllers display and I don't know if the raw data that is recorded is more accurate.
I see little problem in believing that within those parameters, the RoD data is probably quite accurate.
It may well be the extra ROD is attributable to these things
My understanding is that the altitude readout is given in increments of 100 feet on a controllers display and I don't know if the raw data that is recorded is more accurate.
I see little problem in believing that within those parameters, the RoD data is probably quite accurate.
This incident should not have needed the optimising tricks like banking to the good engine. It didn't need to maintain altitude. It just needed a descent rate that was 100 ft/min less than it had. An average descent rate of 500 ft/min for the 14 minutes of flight after the incident would have happily gotten them to the pub that night.
I'm interested that all radio transmissions have been modified in their wording for the report. There is also a discrepancy in the language between the preliminary & final reports. I don't understand why they would not append radio transcripts. If there had been an initial instruction to descend to 5,000 ft, followed by a further instruction to descend to 2,500 ft, then this whole incident takes on a completely different flavour. I raise this because of the ambiguous wording used in the report coupled with a difference in wording between the 2 reports.
For instance, the preliminary report says "ATC instructed the pilot to descend to 2,500 ft". The final report does not cite the ATC transmission, but says "The pilot read back an ATC clearance to descend to 2,500 ft". There is a fair difference between being cleared & being instructed. Which was it?
I'm interested that all radio transmissions have been modified in their wording for the report. There is also a discrepancy in the language between the preliminary & final reports. I don't understand why they would not append radio transcripts. If there had been an initial instruction to descend to 5,000 ft, followed by a further instruction to descend to 2,500 ft, then this whole incident takes on a completely different flavour. I raise this because of the ambiguous wording used in the report coupled with a difference in wording between the 2 reports.
For instance, the preliminary report says "ATC instructed the pilot to descend to 2,500 ft". The final report does not cite the ATC transmission, but says "The pilot read back an ATC clearance to descend to 2,500 ft". There is a fair difference between being cleared & being instructed. Which was it?
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Trent, and likewise yourself
I just tidied up my post, I was referring to Obids post not Akro's. More about the bank angles, drag and RoD.
Agreed on the mode C info.
I just tidied up my post, I was referring to Obids post not Akro's. More about the bank angles, drag and RoD.
Agreed on the mode C info.
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O A, that last post is gold.
The lesson in this report for drivers of this kind of aircraft is - They are built to achieve the required standard, nothing else.
You stack the cards in your favour, short of hurting anyone else.
If there is any doubt, then you haven't stacked enough cards in your favour, start restacking.
If it all turns to sh!t, you go down fighting.
This report says to me that a few less than optimum decisions were made, however AW went down fighting.
In my mind, that makes him heroic.
The lesson in this report for drivers of this kind of aircraft is - They are built to achieve the required standard, nothing else.
You stack the cards in your favour, short of hurting anyone else.
If there is any doubt, then you haven't stacked enough cards in your favour, start restacking.
If it all turns to sh!t, you go down fighting.
This report says to me that a few less than optimum decisions were made, however AW went down fighting.
In my mind, that makes him heroic.
From LeadSled:
Cast your mind back to the last major loss of life at YSSY --- a Kingair that crashed on the seawall around the 34 (now 34L) threshold -- everybody died.
Despite the engine failure advised, the controller did not clear the aircraft No.1 because the pilot did not broadcast a Mayday or otherwise formally declare an emergency. It's all in the BASI report. Had he not been cleared No2 behind a B727, in all likelihood the aircraft would have made it.
Go even further back to the night the TAA B727 on takeoff hit the taxing CPA DC-8. Once again, pedantic and slavish Australian (and non-ICAO) "radio procedures" played a big part in the accident.
Or the Garuda DC-10 ( I think it was a 10) that nearly hit a domestic over Perth --- once again, failed "radio procedures" ---- but if the poor bleeding controller doesn't deviate --- he or she doesn't loose their jobs.
It's a long sad history of Australian "radio procedures" versus effective communications.
As usual coming from you, what complete and utter nonsense!! You appear to have no qualms or conscience in manipulating whatever incidents occur in this industry to suit your own personal agenda(s) and I think that that is quite disgraceful!!!
Please explain how you reach your conclusions in the first two examples?? I am unaware of the Garuda "domestic" that you refer to - please elaborate so that I can compare your version of fact with reality.
Cheers.
VH-MLE
Despite the engine failure advised, the controller did not clear the aircraft No.1 because the pilot did not broadcast a Mayday or otherwise formally declare an emergency. It's all in the BASI report. Had he not been cleared No2 behind a B727, in all likelihood the aircraft would have made it.
Go even further back to the night the TAA B727 on takeoff hit the taxing CPA DC-8. Once again, pedantic and slavish Australian (and non-ICAO) "radio procedures" played a big part in the accident.
Or the Garuda DC-10 ( I think it was a 10) that nearly hit a domestic over Perth --- once again, failed "radio procedures" ---- but if the poor bleeding controller doesn't deviate --- he or she doesn't loose their jobs.
It's a long sad history of Australian "radio procedures" versus effective communications.
As usual coming from you, what complete and utter nonsense!! You appear to have no qualms or conscience in manipulating whatever incidents occur in this industry to suit your own personal agenda(s) and I think that that is quite disgraceful!!!
Please explain how you reach your conclusions in the first two examples?? I am unaware of the Garuda "domestic" that you refer to - please elaborate so that I can compare your version of fact with reality.
Cheers.
VH-MLE
This report says to me that a few less than optimum decisions were made, however AW went down fighting.
In my mind, that makes him heroic.
In my mind, that makes him heroic.
The aeroplane should have brought him home on one engine. Its why we fly twins. I'd like to understand why not and the ATSB has failed us in this regard. Was there an issue with the other engine? Did he follow ATC instruction to descend too literally? There are many unanswered questions.
This has been a good thread with proper debate. Its brought out a range of issues that the ATSB did not. Its improved my understanding and provided food for thought. I think this is pprune at its best.
Merry Christmas. Lets toast missing friends and pray we don't get tested in the way PGW's pilot did.