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Originally Posted by Mach E Avelli
(Post 10261281)
For Con de Rod’s edification. A spurious rudder boost is not a big deal. It CAN be overpowered by a 90 lb weakling. It was only mandated by the FAA because test results showed B200 rudder forces when an engine failed were beyond the certification limit (can’t remember the limit, about 100 lb of force I think.) All it does is assist the pilot by relieving some, but not all, of the foot load until the rudder is trimmed. Presumably they don’t want it relieving all of the load because it could mask the severity of engine power loss. But yes, if the rudder boost system malfunctioned it could add to some momentary confusion, though unless accompanied by some other event or incorrect pilot action unlikely to cause the loss of control seen in this accident. mmm thanks for my edumagation yeah i only have ofver 30 years muti cat lic coverage on type what would i know. the conclusion that the trim position is from the actual positioning of the rudder trim actuator postion. Even if the cable broke it would have had to be itn that postion. It the smoking gun. If the aircraft didnt end up in the position it was ie oppsite to the rudder trim position that it was in you may have arguments about what happened. The elephant is still in the room. |
I reckon over 50 years of actually flying multis and doing a bit of heavy turbo prop certification work might trump 30 years of fixing them when it comes to HANDLING characteristics. Plus, some others here have far more B200 flying experience than either you or I (have you ever actually flown it?). So, instead of challenging every robust reaction to some of your more sweeping statements with "what would I know" your input would be more valued if you left us mere elephants to do the flying and stuck to fixing them. Rod, I am not disputing that it could have been mis trimmed. I am disputing your knowledge of the forces required to overpower the rudder boost. We sometimes fail that (and the FCU) as simulator scenarios and I have yet to see anyone crash with either exercise, even though they sometimes don’t correctly identify the problem initially. We do see some crash initially with engine failures at very low speeds, but they soon get a grip. That is why we use the simulator. It is a shame that the crash pilot did not see regular simulator as vital to maintaining proficiency. Though whether recent sim practice would have mitigated his possible mis trimming of the rudder is debatable. From other accounts probably not. |
Eye toll ewe! ...moving right along, Mach It was only mandated by the FAA because test results showed B200 rudder forces when an engine failed were beyond the certification limit (can’t remember the limit, about 100 lb of force I think.) |
Originally Posted by Connedrod
(Post 10261460)
mmm thanks for my edumagation yeah i only have ofver 30 years muti cat lic coverage on type what would i know.
the conclusion that the trim position is from the actual positioning of the rudder trim actuator postion. Even if the cable broke it would have had to be itn that postion. It the smoking gun. If the aircraft didnt end up in the position it was ie oppsite to the rudder trim position that it was in you may have arguments about what happened. The elephant is still in the room. Will the rudder trim wheel move and the trim tab not move if the cable is broken aft of the stops? Is there an indication from the cockpit that this may have occurred? Looking at the schematic/ stop positions, the rudder trim wheel would work correctly if a failure had occurred aft of the stops? Thanks. |
I have been flying a B200 with some version of an APS-65 that has, in the last 18 months been completely upgraded to an all garmin (g1000) avionics and autopilot system. It doesn’t now, but it did have a rudder trim that was automatic and connected to a servo. I’ve flown C90s, B200s, B300s and 1900Ds and Cs and it’s the first of that type that I’ve ever seen where the rudder trim control would move by itself. You could displace it to one side and it would then wind itself back to close to neutral. I think in the situation above, if the autopilot had been selected, the trim would’ve wound itself back to neutral. I’m not sure this is a feature of all the B200s from that era..our company has another that didn’t automatically trim the rudder..but a much earlier model |
I have flown Efis 84 C90/B200 and for the last 10yrs only Proline 21 ships.
None of this Ac, appr. 5 C90 - 4 B200 - one 350 and one 300 would trim Rudder by itself. The Rudder trimwheel stays where it is. We trimmed even with AP engaged, to get the ball centred. On AP with Engaged YD it would help to slighly press one pedal to help the trim work against the YD. It would do without but that takes way longer. I presume if the cabe breakes, the Trimwheel will move loosely and of course the tab only moves in one direction. But iam not an engeneer, just a Driver. |
One B200 I flew 2 or 3 times had an autopilot that trimmed all 3 axis. IIRC that was a King AP....
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I’m flying a brand new 1000 series B350 and the rudder trim is manual only. |
I’m flying a brand new 1000 series B350 and the rudder trim is manual only. |
Rudder loads - FAR 23
Wrong references inadvertently quoted .. see post # 1116.
One needs to go to the FAA website and amble through the history to check what changes have transpired to the Design Standards .. that's just a bit of easy research for those interested. The KingAir is a pretty old certification so one needs to match the TCDS data to the relevant date rules. |
Thanks for the reference JT. Those forces seem huge, but I assume that is the force applied at the control surface, not the load on the pilot's leg? I doubt too many could bench press 300 lb with both legs, let alone one. I have seen quite puny pilots cope with practice engine failures in DC3s and rather guessed the load was no more than 180 lbs until trimmed out.
As an aside I am currently involved with a DC3 which has more powerful 1350 h.p. engines and the modification for these limited rudder travel from the original to avoid over stressing the fin or hinges. No idea what the load on the pilot's leg would be in a B200 with no rudder boost assist, but guess it would be less that a DC3. |
That’s the wrong para # for this discussion JT, they are structural design loads. Look at 23.143 for controllability and maneuverability where you’ll see the usual 150 lb. |
Mea culpa maxima ... the trouble with looking up stuff when one is three parts asleep .... I'll have to lift my game ... thanks, Dave.
And, for the correct regs ... FAR 23 (at 1964) http://rgl.faa.gov/Regulatory_and_Gu...A?OpenDocument FAR 25 (at 1964) http://rgl.faa.gov/Regulatory_and_Gu...5?OpenDocument and, for FAR 25, a bit later, http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgFAR.nsf/0/701A79191CD71B1286257DC7005718DA?OpenDocument The reduction from 180lb to 150lb came in at 1978 for the heavies. |
Originally Posted by DynamicStall
(Post 10261960)
What is a 1000 series B350? Referring to the serial number?
Most likely Garmin 1000 avionics. |
Originally Posted by DynamicStall
(Post 10261960)
What is a 1000 series B350? Referring to the serial number?
Still has that new aeroplane smell. Still no digital disk gauges though! |
Originally Posted by Mach E Avelli
(Post 10261465)
I reckon over 50 years of actually flying multis and doing a bit of heavy turbo prop certification work might trump 30 years of fixing them when it comes to HANDLING characteristics. Plus, some others here have far more B200 flying experience than either you or I (have you ever actually flown it?). So, instead of challenging every robust reaction to some of your more sweeping statements with "what would I know" your input would be more valued if you left us mere elephants to do the flying and stuck to fixing them. Rod, I am not disputing that it could have been mis trimmed. I am disputing your knowledge of the forces required to overpower the rudder boost. We sometimes fail that (and the FCU) as simulator scenarios and I have yet to see anyone crash with either exercise, even though they sometimes don’t correctly identify the problem initially. We do see some crash initially with engine failures at very low speeds, but they soon get a grip. That is why we use the simulator. It is a shame that the crash pilot did not see regular simulator as vital to maintaining proficiency. Though whether recent sim practice would have mitigated his possible mis trimming of the rudder is debatable. From other accounts probably not. well thats 30 years on type add another 10 on that. So how many flying hours do you have ? |
Some on on here earlier said btw that the CVR power came from #1&2 bus. This is incorrect power for the CVR comes from the HOT bus directly the unit. If it came via 1or 2 bus it can be turned off. That’s why it’s from the hot bus and cannot be turned off. |
On the question of Rudder Boost. In the real aircraft in the event of either a flameout/failure or reducing thrust by power lever, the rudder boost only moves the rudder pedal about 50mm. It's more of a "push this one" than any meaningful rudder force in terms of aerodynamic usefulness. Even at zero thrust or autofeathered you still need full rudder deflection and if you are going to hold it there for any more than about 30 seconds, you'll be needing full rudder trim as well.
I have noticed over the years there is a difference in pilot handling and one can tell those you have practiced a V1 cut verses those that havn't almost immediately.. The V1 cut pilot, rotates, applies full rudder, selects gear up, checks power and trims. Fly the body angle restore the heading. Where autofeather has worked normally there's nothing left to do until cleanup altitude which will take a few minutes. Those pilots who have not trained for a V1 cut, execute the excercise after the gear is up. These pilots tend to hold the rudder force without rudder trim for the whole of the engine failure drill, particularly where the examiner restores thrust immediately after the initial drill is completed. In my humble opinion, there is no substitute for good simulator training in a good simulator with an instructor that knows his ****. |
@ Xeptu:
You are spot on, with your Statement. Mangement of my Company never bought it , when i stated that a King Air is a lot more Work than the light Jets they operated. An Engine Out in a Citation is almost an nonevent, compared to a King Air. Well in a Piston Tin its even more Work, but most Pistontwins will Crash anyway, under real Live Conditions. A King Air except C90 , doesnt have to, but the Margin for Error is very narrow. |
Just research the Moore's Air Charter C-90 accident at Toowoomba a few years ago and you will see what happens with an EFATO.....
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