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Dutch roll

An interesting forum topic coming from the Flight International article on not enough basic handling skills in new airline crews, is the KC135 crash, apparently due to Dutch roll overcoming the A/P.

http://seattle.cbslocal.com/2014/03/13/air-force-releases-kc-135-crash-report/

I thought the yaw damper is always on in some aircraft, and manual control was not possible without it, due to PIO exacerbating the dutch roll tendency of the design.

Oxford (EGTK), United Kingdom

Dutch cuisine is no good, I’ve always said so.

EBZH Kiewit, Belgium

Sounds like an autopilot/yaw damper failure. The aircraft must be flyable by hand without it, certainly at lower levels

Darley Moor, Gamston (UK)

Does dutch roll get worse at altitude? I thought the mandatory autopilot requirement at say FL400+ was due to marginal pitch stability.

Administrator
Shoreham EGKA, United Kingdom

When the rudder / yaw damper design was not changed and is like on the B 707 the autopilot is unable to handle dutch roll. It is a separate system on the rudder (Yaw Damper) driven by an own rate gyro that senses and counteracts dutch roll tendency by a hydraulic actuator. You can switch the elec power source for the system with the Vertical Gyro Switch. Should that not help you have to handfly the aircraft (sometimes over the atlantic )
Less heavy unwanted roll occurs the lower you fly (e.g. FL280-FL310) and the faster you fly. You can stop the tumbling motion of the plane by “kicking in” with short fast aileron inputs against the rising wing. Never use rudder on the 707 in that case. It will tear off the whole tailsection if you use it violently. Rudder is just for engine failure and asymmetric flight and keeping the aircraft aligned during x-wind.

Last Edited by nobbi at 20 Apr 11:18
EDxx, Germany

When the reports of this incident first came out, my first impression was that the crew were, very young. It struck me that the Captain, and the FO were noted as being 27. Now, nothing against young aviators, but, the KC 135 is a pretty serious piece of kit.

I would have thought that it be prudent to have at least one of the flying crew, Captain, to have had a good deal of experience flying this aeroplane. The fact that it is older technology, not something new, MIcrosoft PC, side stick, and computer flown, would give rise to someone in the Air Force recognizing this.

The aircraft literally shook itself apart, and could have been rescued by someone who knew what they were doing. Evidently, this crew, in their inexperience could not, and did not recognize, nor understand the situation they were rapidly getting into.

Sad that three young lives lost. Will anything change??

Fly safe. I want this thing to land l...
EGPF Glasgow

I read these reports (and others from the AAIB) with interest as a potential lesson to learn from, despite the frequently associated tragedy.

As a low hours PPL (about 15 hours post-PPL) and having just transitioned from a C152 to a PA28 I have been wondering how best to continue to develop my practical flying experience. I was asking an instructor about chandelles and dutch rolls the other day and he seemed somewhat surprised that I was interested in these as I will not be going commercial.

I am not sure if these and other techniques would make me a better pilot or if it is something to be learned later, but are there any suggestions on how to develop my skills at this early stage? I have been alternating between a short nav (until I can coordinate with a flying buddy to go further) and some general handling or circuits. Unlike getting your drivers licence where you can then drive around the M25 or local streets until the petrol runs out, I am trying to establish a somewhat more structured approach to bed down my PPL training. I suppose I am at that “what next, now what” stage and whilst I am happy to be flying no matter what I am doing, I don’t want to just put-put about aimlessly doing the same old thing and not really improving. Perhaps I should have posted this on the thread “what stops PPLs continuing” or even in the student forum, but it seems to fit better with developing the basic skills and training to be both a better and safer pilot.

Any suggestions welcome – apologies if there is already a thread on this, just a spontaneous response during my lunch hour.

CKN
EGLM (White Waltham)

Do you really mean dutch rolls?

The chandelle is a non-aerobatic maneuver (pitch and roll do not exceed 30 deg if done right) and can be done in any certified plane. It is fairly easy, once somebody has shown you how.

The lazy eight is also non-aerobatic and is even more gentle, and is a good demo of the conservation of energy. Once upon a time I was really good at them, doing dozens of them all the way along the beach between Seaford and Hastings

Administrator
Shoreham EGKA, United Kingdom

Do you really mean dutch rolls?

I suppose CKN was referring to aileron-rudder-coordination exercises that are sometimes also called “Dutch Rolls”.

Last Edited by blueline at 07 May 14:10
LOAN Wiener Neustadt Ost, Austria

Hello!

… I suppose I am at that “what next, now what” stage …

This is exactly why I chose that forum name, because I am still at this stage after 35 years of flying The day you stop asking yourself that question will probably be the day you quit flying due to boredom.

Regarding what to do: Difficult question because everybody is different. I was never attracted to aerobatics (well attracted maybe, but the hourly cost of a true aerobatic aircraft will take most of the fun out of it for me) so haven’t done much in that direction, but chandelles and “dutch rolls” (whatever you mean, hopefully not the real ones!) can not harm. Will they make you a better pilot? Probably not.

What I think is really important is speed control at all times (something usually not taught properly during the PPL course) because it is essential once you progress to more complex and higher performance aeroplanes. Practise to climb at the correct speed (+/- one or two knots, otherwise the exercise is pointless), configure your aeroplane at defined speeds (flaps up and down will be all for the moment) and most importantly: Fly your approach at the correct speed. Familiarise youself with Vref and Vtgt for your aeroplanes and try to hold that on every approach. Always fight for the centreline on every landing (something many beginners do not care too much), the day will come when you fly a crosswind landing into a small strip and then it will be to late to learn the technique.

Happy landings
Max

Last Edited by what_next at 07 May 15:02
EDDS - Stuttgart
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