I have never had anything as low as 100fpm. I wrote 200fpm to be a bit on the conservative side. I usually see nearer 250fpm, with the 135hp engines.
There are several “moments” caused by different things when you lose an engine . Generally the most significant are the yaw and the roll towards the dead engine. If you didn’t notice that you had lost an engine or you didn’t react you certainly could or should I say will lose control. But that’s what training is all about.
The half ball or 3 to 5 degree bank into the live engine does make the control a little easier on the live leg ie you don’t need so much pressure, however to go over the 5° goes past the limit of whether or not it is doing something useful and can in effect do the opposite for instance the aircraft will start to turn. Banking to within 3° to 5° is seen these days as another complicstion to an already difficult situation, which is why many instructors these days do not teach it preferring the wings level and ball in the middle.
I have seen reports of twins rolling over due to EFATO and I have seen reports of the Twinkie problems due to low level Vmca training but most of these were many years ago and their causes have for the most part been mitigated by changes in the training regime. I believe if you research accident reports you will see frightening reports for the Cirrus, Cessna and Beech during their early days to name but a few.
Some aircraft have successfully shaken these off eg Cirrus, by introducing the parachute and extra training, others like the V tail Beech are still thought of as doctor killers and the same goes for twins. The weird thing is that the people who spread these stories are pilots themselves.
I know several pilots who were long time owners the V tail Beech35 and I have flown as a passenger with them. They were passionate about them and I was given no reason to feel them unsafe. For me it is the same with twins I have yet to come across one I didn’t like or in which I felt unsafe. Although I will admit that the 3/4scale Mosquito was a little uncomfortable to sit in.
gallois wrote:
which is why many instructors these days do not teach it preferring the wings level and ball in the middle.
Interesting, certainly not the case round here. In fact my instructor put a lot of emphasis on the combo of bank AND rudder as did the DPE during the checkride.
gallois wrote:
The half ball or 3 to 5 degree bank into the live engine does make the control a little easier on the live leg ie you don’t need so much pressure, however to go over the 5° goes past the limit of whether or not it is doing something useful and can in effect do the opposite for instance the aircraft will start to turn. Banking to within 3° to 5° is seen these days as another complicstion to an already difficult situation, which is why many instructors these days do not teach it preferring the wings level and ball in the middle.
There is no need for any bank angle if you have sufficient performance and control. If you are able to climb sufficiently at Vyse with wings level, that may be more sensible, however you will be in a slight slip, roughly equivalent to having the ball half way out of the box. But it depends on the aircraft. If you need all the performance then a slight bank of 2 or 3 degrees will remove the small side slip and require less rudder input. For something like a baron you might get 100ft/min more. I have a table from a paper that suggests 2.5 degrees is needed for a baron to achieve zero side slip and a pa-44 needs 2 degrees. But feathering the propeller is much better for performance and control. For a jet it is probably more like 1 degree* , and you probably don’t need the extra performance. (*there is a formula to estimate)
However if you find yourself at Vmc with a rear CG, prop wind-milling, you should expect to need the 5 degrees for control, unless you know this was not used to determine the Vmc. Using 5 degrees will result in a lower climb rate than zero side slip AoB and it might also be lower than wings level/ball centred, but you should be able to control the aircraft at the red line long enough to increase speed and feather, so you don’t need as much bank angle.
The third page of this from the FAA is worth a read.
Quote
I have seen reports of twins rolling over due to EFATO and I have seen reports of the Twinkie problems due to low level Vmca training but most of these were many years ago …
Unfortunately this is still happening nowadays (last year)
http://www.crash-aerien.news/forum/crash-au-castellet-t41447.html
Interesting. It seems the cause all started with a miscommunication between instructor and student. Also interesting if I read correctly it was a Twinkie with counter rotating engines. Thank goodness the student, instructor and passenger all got out safely.
I note the report references another accident after which the UK sent out an advisory to all MEP pilots.
Ted wrote:
However if you find yourself at Vmc with a rear CG, prop wind-milling, you should expect to need the 5 degrees for control, unless you know this was not used to determine the Vmc.
Following on from my previous post, having only flown twins derived from designs from the 50s. I was curious about a design from this century the DA-42. From the POH that I found on the web a Vmc of 65kts IS calculated using 5 degrees of bank.
Also this demonstration shows the test pilot establishing a slight bank probably around 2.5 degrees* when climbing out at what I presume is Vyse. In the entire video he never comes near the conditions of Vmc so there is no need for the full 5 degrees. (*if I estimate it correctly with Photoshop)
from 271 seconds
if you follow the link (I can’t get embedded youtube with a start time to work, @peter?) [ correct; it doesn’t work ]
The following video of a duchess which I used to do a fair bit of training with is interesting (from 373 seconds)
It suggests at least in these tests, when the aircraft is near/or at the stall, with asymmetric T/O power, that using 5-10 degrees of bank the aircraft could be controlled indefinitely. If the same test was conducted wings level it would enter a spin. So being beware that you may need the full 5 degrees at Vmc is IMHO important!
I would hope that any twin pilot would avoid flying at red line speed or at least to be well aware of the risks entailed.
With both engine idle, not a big deal…
They are blessed with two red lines, Vmca and Vne :)
Vmca with both engines windmilling would be interesting as it is quite high up the back end of the drag curve and not too far from Vs, in a typical MEP probably around 2,000 fpm plus rate of descent.
