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-   -   Crosswind Landings in the BE76 (https://www.pprune.org/professional-pilot-training-includes-ground-studies/240338-crosswind-landings-be76.html)

Pole Hill 23rd Aug 2006 17:00

Crosswind Landings in the BE76
 
Hi,
I didn't know where to put this question, so I'd thought I'd try here!
I'm currently doing the MEP rating in the BE76 Duchess. But I am finding crosswind landings quite a challenge, although I've never had a problem when flying light singles. I use the cross controls technique.
I can't quite remember exactly what happened on the last flight, but with a 20kt crosswind (from the left), it felt like there wasn't enough rudder authority when I wanted to 'kick it straight' and put the wing down into wind. I was landing asymmetric, so had a bit of left rudder trim in, but I was pressing really hard on the pedal! I was using full flap.
What could be the possible cause? The demonstrated crosswind limit is 25kts for the BE76.
Thanks,
POL

BlueRobin 23rd Aug 2006 19:32

Do both engines on the Duchess go the same way? Add their torque to a left-quartering wind and I wouldn't be surprised if a significant push is required.

Jannik23 23rd Aug 2006 19:47

I wouldt use full flaps on a crosswind like that - try less flaps

Jannik

speedrestriction 23rd Aug 2006 20:25

A forward C of G will noticably increase the forces required to obtain large rudder (and elevator) deflections. This often happens on training flights with two bodies up the front and nobody in the back.

You might get more info in the Tech Log forum.

SR

Pole Hill 23rd Aug 2006 20:41

Thank you all for your replies :ok:
claycomm: Thanks for that, I'll keep that in mind for the next time, and see how it works out.
BlueRobin: No, they are counter rotating.
Jannik23: Good point, thats what I normally do on the singles, I'll try flapless next time.
speedrestriction: Thats an interesting point. The rudder will be more effective though with a forward C of G due to rudder having a larger moment arm, so this would work in my favour.
POL :)

Keygrip 24th Aug 2006 01:39

Land on the other end and have the cross wind from the other side?

NavPilot 24th Aug 2006 05:24

The full flap, I my opinion, could be a real challenge. I'd try a partial flap...not essentially a flapless.

silverknapper 24th Aug 2006 08:45

Yeah agree with above. 20 knots must be nearing limit of rudder authority. I was always taught not to use the last stage of flap if I was asymmetric. Less drag will mean less power needed all the way down leading to less rudder needed to counteract the yaw from live engine. Also less trim changes below ACH when you have enough to think about.

speedrestriction 24th Aug 2006 12:11


Originally Posted by Pole Hill
The rudder will be more effective though with a forward C of G due to rudder having a larger moment arm, so this would work in my favour.

True, it will be more effective, but that isn't much use if it is too difficult to get the pedal all the way down. I found out the hard way. When you come to the MEIR the forward C of G helps makes the airways and approaches a doddle, but just wait for the assymetric go around.......I was walking crooked for a week!!

SR

NavPilot 24th Aug 2006 14:17


Originally Posted by speedrestriction
but just wait for the assymetric go around.......I was walking crooked for a week!!
SR

SR
:ooh: ;) Was that on a duchess?

Pole Hill 24th Aug 2006 21:05

NavPilot & silverknapper: I'll put your point accross to my instuctor when I next see him, it makes more sense to only use partial flap... :)
speedrestriction: I see what you mean. :ok: Oh, and the asymmetric go around, with 3 on board, 1hr out of the fuel tanks and on a hot summers day, very interesting.
Many thanks,
POL

speedrestriction 24th Aug 2006 22:19

NavPilot: Seneca.

SR

Oktas8 25th Aug 2006 05:59

Pole Hill - am I too late to respond? I was mindlessly browsing and saw your post!

I second KeyGrip's suggestion - with left rudder trim applied due to a failed engine, you would need right rudder to keep straight in the flare. You need even more right rudder if there is a crosswind from the left. Might explain the high rudder forces you experienced.

Couple of people above have mentioned running out of rudder authority in a crosswind landing. Not a likely scenario, as most light aircraft (and all twins) have huge rudder authority. Running out of aileron authority is much more likely. The cure is easy - land flapless at a higher speed, giving greater authority to your ailerons. But that isn't your problem I suppose...

Cheers,
O8

kala87 25th Aug 2006 09:42

Pole Hill:

Also did my MEIR in Duchess. I used to find that in a x-wind (with both motors running or assymetric), the best technique was to use quite a lot of into-wind aileron just before touchdown. Counter the tendency to turn into-wind by using a much opposite rudder as you need. It can be a bit of a juggling act for a few seconds getting the right balance between amount of rudder vs amount of aileron, all the time keeping the aircraft aligned with the rwy centreline. The into-wind main wheel would usually touch down a second or two before the other wheel, but that's normal. I don't recall ever running out of rudder authority, and I never grazed a prop (so far!) Has anyone out there actually bent a prop on a light twin using this method?? In 20 kts of direct x-wind, less then full flap is probably a good idea.

Pole Hill 25th Aug 2006 18:09

Oktas8: Absolutely agree, land from the other end. The problem is that the airfield is busy with GA and airline traffic, so I wouldn't be able to do that. Its something to keep in mind though in the event of an approach with a real engine failure and a significant crosswind component. Flapless or partial flap seems to be the most appropriate configuration.
kala87: Ok, I'll bear that mind. Now you mention it, I don't think that I've been putting in enough aileron either. My whole technique needs sorting me thinks :O
I'll get it right eventually!
Many thanks,
POL

Piltdown Man 25th Aug 2006 22:27

Land into wind wheel first, then the other one followed by the one at the front. Don't bother with the rinky-dink, time-it-to-the-millisecond malarky of de-crabbing. And a question for you:- Is the crosswind limit you quoted valid for single engine!

Jimmy The Big Greek 26th Aug 2006 08:46

I have 500 hours in the dutchess and I must say that it has good crosswind landing performance. I find it much easier to to land the dutchess then the C-172 in a crosswind.

I use a combination of the crab and cross-control. (crab in the approach crossed at the last part of the landing).

The dutchess is a very stable aircraft sometimes when I was experiencing strong crosswind or if I was heavy I used only 10 degrees of flaps or no flaps. This will increas the aircrafts responsivnes. Another trick that you have to try is to have a little bit of power during the flare (the throttle just about 2-3 cm from idle) and close the throttle at the last part of the flare, if you try this youre landing will be perfect and you also increase a little bit of rudder effectivness.

The dutchess is a wonderfull aircraft with a little bit experience you will love it.

pushapproved 26th Aug 2006 08:59

When you go below ACA/H, i.e. you're commited to a landing, you could try moving the rudder trim towards neutral, this will reduce the force required by your leg in the flare/hold off...

Pole Hill 27th Aug 2006 20:18

Piltdown Man: Good point. Thats something that I have totally forgot about. :O
Jimmy The Big Greek: I love the Duchess already! Out of curiosity, with no significant crosswind, all engines, what speeds do you use for the approach with flaps? I use 85kt final and 80kt threshold for all engines and asymmetric. I find that by using these speeds, the aircraft tends to float a little before the nose can be gently raised as the speed decays. I think that this was my problem, while the aircraft was floating for them few seconds, I was battling with the gusting crosswind.
pushapproved: I do this already, though I probably didn't take enough trim off in the flight that I described in my first post, but thanks for the tip anyway :ok:
Thanks,
POL

Jimmy The Big Greek 28th Aug 2006 08:33

The speeds you are using are ok for single-engine and normal operation (blue line). For short field landing I use 70.

When you float over the runway it is very importand that lower the wing in to the wind.


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