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Gotta love the old LAME vs Pilot arguments on engine operation...
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Originally Posted by Squawk7700
(Post 9733555)
Gotta love the old LAME vs Pilot arguments on engine operation...
Squawk it appears to me that it is more a case of ex military officers having problems with the ORs disagreeing with them. I was once at a debrief after a Caravan had an engine roll back to 56% Ng in flight and the pilots dead sticked about 15 mile to a beach. Memory is a bit iffy, Taily and can correct me, but during restart attempts the engine was shut off and the Ng dropped to zero, subsequent restarts didn't achieve self sustain RPM. Propellor rotation will only rotate the power section, it will not turn the gas generator. As Ramrod has previously explained, to achieve the 18% or more gas generator speed to effect successful lightoff, one needs a high airspeed for ram air to spin the compressor section to this RPM. As Connedrod has explained, without sufficient Ng the oil pump pressure will not be high enough to deliver sufficient pressure to the CSU to pump oil to maintain propellor blade angle and may in fact come back to feather. |
Eddie
We know the engine was operational at the time of impact. This is because the prop was not in a freathered position. At least postion of the condition levers may have been in two possibly positions of grd idle of 52% or flight idle of 72% ng. It should be at the later. At in 72% it would not have zero tq. This is the min speed of the N1 if the power lever is brought back to the idle position. With out oil px the prop will not and cannot stay in fine pitch. In this case the posibity of auto freather may or may not have worked. Auto freather only purpose is to help the pilot from removing power from the wrong engine if there is a problem. If the engine has a completely lost power from the cold section it will freater its self. It can be seen from the pics that one of the engines was not in the freathered position. We at this stage ate only think it was the left engine which has had the problem. Astb reports say that both engines internal assy where operational. |
What's freather?
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We know the engine was operational at the time of impact. This is because the prop was not in a freathered position. ... two possibly positions of grd idle of 52% or flight idle of 72% ng. With out oil px the prop will not and cannot stay in fine pitch. In this case the posibity of auto freather may or may not have worked. There is plenty of oil pressure at all normal engine speeds. I believe there is plenty even at speeds as low as 20% Ng. During start, the prop begins to unfeather well before the Ng is fully up to speed. Auto freather only purpose is to help the pilot from removing power from the wrong engine if there is a problem. |
The lever can be set at intermediate positions |
We talking the fuel/condition lever?
Yes it can be set at intermediate positions between low and high idle. |
Originally Posted by Car RAMROD
(Post 9733739)
We talking the fuel/condition lever?
Yes it can be set at intermediate positions between low and high idle. |
Just now read the PT6 manual. Idle reset has only two positions. There appears to be no intermediate position. If you have it in low idle you can increase RPM with the throttle.
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Originally Posted by FGD135
(Post 9733708)
You cannot draw that conclusion from that evidence.
King Air operators have a variety of policies in regard of where the condition levers are set. For the 4 bladers, I believe the low idle setting is 60%, not 52%. The lever can be set at intermediate positions (e.g. 62%). If they needed airconditioning that morning, it is possible the R engine was at 62%, with the left at 60%. It is possible both were at 60% - or 62%. It is unlikely that both were at 70%. More lilely they should be at 70% high idle. This should be used for take off and landing. The A/C should be in in the OFF position for take off and landing. Contradicting yourself. You seem to be saying that with the loss of oil pressure, the prop will feather. Then you say that, without oil pressure, the autofeather may not work. (!) No saying that with out oil px the prop will freather. But as the engines are working it may not work as the Tq is above the low setting to activate. There is plenty of oil pressure at all normal engine speeds. I believe there is plenty even at speeds as low as 20% Ng. During start, the prop begins to unfeather well before the Ng is fully up to speed. Are you joking 20% is around light off Ng. The engine is not even close to self substanting its self. 50%Ng is when the engine will hold its own. Wrong. The pilot can still inadvertently feather the good engine. If the bad engine has autofeathered, the good can still be manually feathered. |
[QUOTE=FGD135;9733708]You cannot draw that conclusion from that evidence.
We sure can. Atsb have stated it. Indication marks on the roof are port to starboard in a forward diection. Not fwd to rear in a fwd diection meaning the prop was not in feather position. Meaning the prop had oil px. Meaning the only way tne prop can have oil px is if the engine was running. This means the egine was above 50% N1 at inpact. And when the correct prop speed is determined if its below min gov speed a Tq value will be able to be determined. Above min gov it may not be able to be known. |
Does the report stating that the engines were operative relate to the state of the fuel system?
Mickjoebill |
Originally Posted by Eddie Dean
(Post 9733820)
Just now read the PT6 manual. Idle reset has only two positions. There appears to be no intermediate position. If you have it in low idle you can increase RPM with the throttle.
Are you talking about up at the fcu? Of course you can increase rpm with the power lever (throttle). You can also increase it with the condition lever- anywhere between the low and high idle positions. Push the lever forward a bit, stop, it stays there with a corresponding increase in idle speed. Mick, the report doesn't say the engines were "operative". It just says that the cores were rotating at impact but they don't indicate at what possible speeds. Ram airflow will spin the core of a PT6. All that highlights is for example it hadn't seized up/disintegrated etc. State of the fuel system cannot really be figured out directly from the information at hand. I'm sure they'll investigate what components they can, and if it was refuelled locally I'd imagine they'd already have copies of the delivery docket and samples from the truck. |
In keeping with The Australian's propensity for dishing up largely confected pap on its Aviation pages, today we're treated to Ean Higgins' ATSB report ‘may have prevented Essendon plane tragedy’. Higgins reports that Dick Smith contends that;
THEN everyone would have lived happily ever after. |
I'm hoping that's not an even ball-park close report of Dick's views. If they are, it is sad to see the onset of dementia in a once-great Australian. :{
The safety regulator investigated and took regulatory action against Mr Q in relation the Hotham incident. |
Ah Dick. Do you really think that IF he was found at fault for Hotham, and grounded for a time period (unlikely, let alone long enough to cover the time period of the accident flight) that this accident wouldn't have occurred?
That's a very, very long bow to draw. Mick, that's indeed a lot of IF's! |
Originally Posted by Lead Balloon
(Post 9734459)
I'm hoping that's not an even ball-park close report of Dick's views. If they are, it is sad to see the onset of dementia in a once-great Australian. :{
Dick Smith, a former chairman of the Civil Aviation Safety Authority, said it was “completely inexcusable” that the ATSB had still not completed the report of its investigation of the September 2015 incident at Mount Hotham. He told The Australian that had the ATSB completed its investigation and report within a reasonable timeframe, and concluded that pilot Quartermain had engaged in poor airmanship endangering lives, he might have been grounded. In that case, Mr Smith said, Quartermain would not have piloted February’s flight in which he and four American passengers died when the Beechcraft King Air crashed into a shopping centre nine seconds after it took off from Essendon airport. |
Mick, the report doesn't say the engines were "operative". It just says that the cores were rotating at impact but they don't indicate at what possible speeds. Ram airflow will spin the core of a PT6. All that highlights is for example it hadn't seized up/disintegrated etc.
State of the fuel system cannot really be figured out directly from the information at hand. I'm sure they'll investigate what components they can, and if it was refuelled locally I'd imagine they'd already have copies of the delivery docket and samples from the truck.[/QUOTE] Two men say they Jesus one of them must be wrong. Ppruners say prop speed between 1586 and 2000 rpm. For this the engine must be running. Slash marks indication show prop not in feathered position. Prop will feather with no oil Px from the cold section. Ram air will not supply enough oil to hold the prop in fine without oil the cold section working. So is the fuel system working or not. |
Probably shouldn't try getting into the argument but here goes anyway.
Relative wind, no seizure, ram airflow. Windmilling. Hence the term. There is enough airflow through the compressor section driving the oil pump, to the prop governor, to keep the blades towards fine. If not, please explain the windmill start procedure! I'd say go and try it- but not in a 4 blader because the drag sucks! Conned, please leave the discussion to those who know what they are talking about. |
Car RAMROD,
I think it best not to engage with Connedrod. It is quite apparent that he has poor written english, but having debated him over the last few days, can report that he his comprehension of written english is similarly abysmal. It is impossible to have a rational debate with this kind of person. You are wasting your time. To everybody else, I urge no engagement with this individual, and strongly back this statement from Car RAMROD: Conned, please leave the discussion to those who know what they are talking about. |
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