King Air down at Essendon?

[FGD135]

The next Thing everybody i know, does in an OEI Scenario is: Rudder Trim full on!!

But this scenario was not OEI. Maybe the pilot thought it was, but the wreckage examination found that both props were turning at 2000 RPM (approx), and both engines were delivering full power (approx).

He stated that there is a possible fcu drive shaft fault that results in a runaway engine and believes this is what happened. Looking at the amount of damage on the wreckage, how could this not be discounted from what happened?

Examination of both engines and both props showed that all were operating normally. For both engines, the prop shaft failed in the same place with an "almost identical" fracture surface. This could not have been the case if both engines were not at the same power and RPM.

[cattletruck]

An admission to start with: I've never flown a twin prop, so the following is just my speculation.

The clue is the relatively large number of mayday's that were issued before the impact. XYTG's view I feel is very close to the money.
Perhaps during the take-off run the pilot realised the rudder trim was set incorrectly. Perhaps at the time of realisation of this he was committed to rotate. Perhaps he was well aware that there was an upper airspeed limit under this trim configuration so he reduced power. Perhaps he got the power reduction change wrong during the stressful circumstances and overdid it with an already overweight aircraft. Perhaps he gave it the welly when he realised his mistake but it was too late as the plane started descending. Perhaps he realised that the situation was no longer recoverable and issued as many mayday calls as he could before impact.

Purely my speculation.

[Capt Fathom]

Purely my speculation

Hmmm... That was way too many Perhaps.
Perhaps you could speculate somewhere else!

[cattletruck]

Perhaps, but that wouldn't get up the eyre of the know-alls would it.

[Capt Fathom]

I couldn’t comment. You’d have to ask them!

[717tech]

Originally Posted by holdingagain

Tech, we just commented on this, refer posts 1012 / 1016 / 1018.

Missed that bit. Cheers!

[Pinky the pilot]

eyre

???????

[His dudeness]

Is that scenario on a training program these days ? One got beaten to death with engine failures but Rudder trim off to one side ? I have about 4000hrs+ in B200s (most of that in Raisbecked airplanes like the crashed one - quite capable aircraft, still fly one occationally), used to give type ratings on aircraft and whilst I did a lot of VMCA demonstration, I never dared to put such a scenario up. And a fully loaded Raisbeck B200 will climb on one donk with the gear down. 300-500fpm IIRC (at least ours did, lets put it that way)

[Propsforever]

In my Opinion it takes one-two three to retrim the Rudder. I did it quite a few times in a hurry when after a Single engine Go, i got the second engine back.

@ His dudeness: A fully loaded loaded non raisbeck B200 climbs acc. to my Manual (BB1716) with 3,8% @ 106KT
Flaps Appr. thats 400ft/min. flaps up its 5,5% @ 121KT so around 700ft/min.

Somewhere in the Flight Safety Training Manual is written: Gear down costs you app. 450ft/min climbrate - Flaps App around 100ft/min - Flaps full app 500ft/min

Add the Sideslip and it wont climb with the Gear down, "if there is a Problem with one Engine".
With 2 Donkeys Running there should Show around 2400ft/min or correcteted for the Overweight some 2200ft/min.

The whole TO Looks in the Video similar to an Engine out, not like a Sideslip, that wont kill 2400ft/min of Climbrate.

Lets say it that way: I have seen People Operate with 13000+lb on 800m Rwys in similar Weather. And i know, with 2 Engines it will work. And Every "Experienced" KA Pilot is watching and working the Ball during the whole flight.

And by the way, i was CRI/TRI on the King Air until i decided to not revalidate it.

[His dudeness]

Originally Posted by Propsforever

In my Opinion it takes one-two three to retrim the Rudder. I did it quite a few times in a hurry when after a Single engine Go, i got the second engine back.

Thats true, but you knew that you were out of trim. Now this guy did a rolling takeoff, which can be a handful if one engine bites and the other doesn´t - and might have greatly "helped" to cover up the mis-trim.

Lets say it that way: I have seen People Operate with 13000+lb on 800m Rwys in similar Weather. And I know, with 2 Engines it will work.

IIRC the C-12 (the military version of the B200) is flown to 13500lbs MTOW. With 2 engines that is no issue at all as you said...

And by the way, i was CRI/TRI on the King Air until i decided to not revalidate it.

me too, but these days I just think EASA (and "my" authority) should copulate with themselves...

[Lead Balloon]

A question for those with extensive experience on type: During a ‘normal’ pre-flight inspection, is the rudder trim set to full deflection in one direction to facilitate an inspection of some component, or to confirm the operation of some indicator?

I suppose this is just another way of asking OA’s question: In what circumstances was the rudder trim set to full left in the first place?

I realise that’s not an excuse for missing the trim setting before taking off - if there was an indication that it was not set where it should have been - but the ATSB would have us believe that someone took it upon themselves to board the aircraft and set the rudder trim full left before the flight. Who and why? Or that it was set there at the end of the previous flight. Who and why?

It used to be that all of the holes in the Swiss cheese were considered important. I assume these days that if a pilot takes off with mis-rigged ailerons the cause of the accident will be the pilot’s failure to confirm the controls were operating in the correct sense before take off, and the reason for the mis-rigging an irrelevant bagatelle. (And before you have an attack of the vapours, connedrod: I do realise the accident aircraft in this case had been flown numerous times post-maintenance.)

The fact is that if the ATSB’s theory is correct and the final hole in the pieces of the Swiss cheese is the pilot’s failure to set the rudder trim to the correct position, it inexorably follows that the previous hole was the trim being set to full deflection before the flight. Be good to know who and why. The subsequent litigation will do this job for ATSB.

And the gist of discussions on first world aviation discussion boards is why the aircraft wasn’t controllable and performing better if both engines were delivering full power, despite the rudder trim position and the undercarriage being down.

[junior.VH-LFA]

As has been mentioned previously, it is a flight manual requirement for all three trims to be run through FULL deflection checking for free movement and lack of binding etc.

it is extremely conceivable that a distraction occurred resulting in a failure to reset the rudder trim during this check, it’s happened to me before too. The rudder is also the last of the three trims to be checked.

But I did (thankfully) pick up my error during the before take off checklist. So I do understand, especially on a busy morning, if you were under time pressure, fatigued, etc how this could happen. It is tragic, but I guess avoidable also.

[Lead Balloon]

Thanks Junior. That’s helpful.

[Squawk7700]

someone took it upon themselves to board the aircraft and set the rudder trim full left before the flight.

Perhaps even some kids / grand kids / hangar rats were fiddling around in the aircraft whilst in the hangar or someone having a sit in the cockpit. Certainly not out of the question, without knowing the security arrangements there. I’ve found my transponder on an unusual code on the odd occasion.

Read the first two paragraphs of the below link and this appears to be a multi-crew arrangement:

http://www.ntsb.gov/investigations/A...s/AAR1503.aspx

[georgeeipi]

I certainly concur with His Dudeness that engine failures on take-off were 'beaten' into to us. Even in a two crew environment the pre-takeoff brief included considering the course of action if we lost one before and after v1. So I would not be surprised that is what the pilot thought was happening. It seems reasonable that he didn't abort the take-off at the early stages because the asymmetry would have presented itself gradually. And once he was airborne where the asymmetry was more clearly defined he may have waited for the auto-feather to do its thing only to realise, too late, it wasn't going to happen. I am not type-rated on the B200, but it was common practice in other aircraft type to go through the 'dead-leg dead engine' procedure. If he had done that I imagine that he might have been extremely surprised to discover that the yaw only got worse if he reduced the power on the 'dead' engine. At that point I can see how confusion would set in. Perhaps he reduced power on the other engine as well in an attempt to reduce the apparently inexplicable yaw?

Why are we speculating? Because we don't have the recordings that would tell us what actually happened. I read through the ATSB report and in the absence of those recordings the findings seem quite reasonable. The only thing I was disappointed with was that the ATSB didn't try throwing an out of rudder trim scenario in the simulator at a bunch of experienced, but naïve B200 pilots and see how they responded. Anyway, I am sure that scenario will become part of the future turbo-prop training regime.

[megan]

As has been mentioned previously, it is a flight manual requirement for all three trims to be run through FULL deflection checking for free movement and lack of binding etc

Are you sure about that? My manual is old (last update 2004) but makes no mention of running the trims through their range to check for binding etc. The first mention of trims is the cockpit check prior to the walk around, and merely says to set the trims to "0". Prior to take off there are another four occasions when trim setting is called for to be checked. Page 45 of the report cites the same. In fact I've never seen a checklist that called for running the trims through their range to check their correct operation, binding etc.

[Squawk7700]

We’re taking about CVR voice only recordings aren’t we? Or does it contain black-box type control monitoring too? Just wondering how the voice recording would actually have helped with this for a single pilot operation.

[mattyj]

Are you sure about that? My manual is old (last update 2004) but makes no mention of running the trims through their range to check for binding etc.

mine neither

[MickG0105]

Can someone who currently flies a B200 please comment on the view of the rudder trim wheel from the left hand seat. Having looked at a number of cockpit photos it appears that because the rudder trim wheel is oriented slightly more to the horizontal and is located down and to the right of the aileron trim wheel that the pilot's view of it may be somewhat restricted if not obstructed.

[FGD135]

... the SIM pilot is not reported as having made any comment on the controllability at the speeds exhibited in the incident. The SIM pilots comments are that the yaw was manageable at lift off, then challenging, then uncontrollable after an unspecified period with the aerodynamic load at 140 knots and above. The aerodynamic load can be expected to increase with the square of airspeed - so the rudder force required to correct the LH rudder trim at 140 knots will be very different than at 108 - 112 knots.

Old Akro,

I think you have oversimplified the situation. There are many reasons why the simulator performance would be too dissimilar from the real aircraft's performance to draw reliable conclusions. Being a level D simulator means that the control forces (e.g. rudder forces) for regular assymmetric flight would be accurate, but for the case of symmetric flight with full rudder trim, it appears there is no certification requirement for accurate representation of flight characteristics and control forces (based on my limited research).

For a simulator to faithfully exhibit those things would require the manufacturer to possess the data for them, and from my reading between the lines of this report, it appears this manufacturer does not.

And, I would suggest you are not accounting for all the aerodynamic effects that were contributing to the yaw moments that morning. The fin/rudder would have been contributing a nose left (NL) moment, sure, but there was also a significant NR from the fuselage body aft of the CG. But at such high angles of sideslip, I believe the fin would have been somewhat stalled, thus reducing the NL moment.

So, nowhere near as straightforward as you suggest to make an armchair adjudication on the controllability of the aircraft that morning.