View Full Version : 212 Hydraulics off
Torquelimited
23rd Jun 2016, 06:38
Is it possible to make a controlled landing with a Bell 212 dealing with a dual hydraulic system failure?
gulliBell
23rd Jun 2016, 06:53
A single word answer is not allowed by the forum....the answer is yes.
Democritus
23rd Jun 2016, 08:53
It's 43 years since I last flew a Bell 212 so excuse any memory fade but at that time I'm sure we did practice landing with both hydraulics off during our conversion to type. If I remember correctly the only gotcha was that once lowered you could not raise the collective again.
John Eacott
23rd Jun 2016, 09:16
From memory it's much the same as the UH1 with Hyd off, single system doesn't leave many options.
Bloody hard to move the collective, if at all.
Phil
John Eacott
23rd Jun 2016, 10:29
Bloody hard to move the collective, if at all.
Phil
Not for us youngsters, Phil ;)
LOL!! And if you've had your weetabix! :)
Phil
MichaelCollins
23rd Jun 2016, 13:17
I seem to remember it was controllable down to about 40kts. After that the controls could not be moved and you become a passenger, so you had to set up a long final approach with a low rate of descent for a run on landing and hope for the best. Ah, happy by-gone days!
SASless
23rd Jun 2016, 13:23
212 Hydraulics off....not a problem....hovering is bit of work but have done that.
Trick on the Cyclic is not try to "move" it like normal...but just apply pressure in the direction you wanted it to move and let the "motoring" move it for you....otherwise having a breakfast of Gorilla Grits was required.
Leading with Pedal movements during Collective adjustments made it easier to handle.
The Collective was no problem.
The S-58T with both Hydraulics out was more fun than the 212....I always got the impression I was carrying the Helicopter in my Left Hand when the Aux Hydraulics were "OFF".
Three Lima Charlie
23rd Jun 2016, 14:30
Many years ago during my offshore days, we did our annual check rides and practiced landings to helipads on oil rigs and ships with emergency governor, both hydraulics off, single engine, etc. etc. (Not all at the same time!)
albatross
23rd Jun 2016, 16:20
Long time since I drove a 212.
As I recall the. no hydrualics procedure. it was advisable not to lower the collective below 35Q or it would be just about impossible to raise again.
Not hard to arrange a safe arrival profile.
oleary
23rd Jun 2016, 23:25
In the '70's and '80's we did "both hydraulics off" zero speed landings with the 212 as part of our annual training.
As someone else said, try not to "stir the stick". Also, the collective when lowered is very difficult, but still possible, to raise.
Someone mentioned the single hydraulics Huey. This is a very different critter because all the 205 variants had inboard fittings on the head which allowed adjustment of (collective) hydraulics off forces. The 212 has no such inboard fittings so the collective force is set by the straps.
John Eacott
23rd Jun 2016, 23:53
In the '70's and '80's we did "both hydraulics off" zero speed landings with the 212 as part of our annual training.
As someone else said, try not to "stir the stick". Also, the collective when lowered is very difficult, but still possible, to raise.
Someone mentioned the single hydraulics Huey. This is a very different critter because all the 205 variants had inboard fittings on the head which allowed adjustment of (collective) hydraulics off forces. The 212 has no such inboard fittings so the collective force is set by the straps.
Thanks for the reminder: the conversion was many moons ago and in NZ, where everything works slightly differently ;)
oleary
24th Jun 2016, 03:43
John, we are the keepers of a large volume of totally useless information.
Ain't it grand to have survived a lifetime of this biz? ;)
Helicopter doctor
25th Jun 2016, 05:19
When converting a 205 to the 212 rotor system, the 212 hub is used but the inboard fittings are replaced with a special STC part which applies a different bias to the TT straps. This allows the collective to be raised and lowered, hydraulics off, much like the stock 205 with single hydraulic (No1) collective servo switched off, but the fittings are not adjustable like the stock 205 fittings. Worked OK. A "neutral force" range in the cruise torque settings, but progressively harder to raise or lower and the high and low end.
Doc
GCMOIR
27th Jun 2016, 05:46
Hi SAS, just picking up on your comment about flying the S58T with both hydraulics off. If you did this there must have been something wrong with the ship because the electrical switches are so wired that it is not possible to turn off both systems at once. Having observed the feedback through the cyclic when starting the rotor without the electrical ground hydraulic pump running gives an indication of the forces at play here and I seriously doubt you could control the ship in flight with both systems off. You're right about the "weight" of the controls when Aux hydraulics are off, they are very heavy.
SASless
27th Jun 2016, 10:51
Upon reflection my memory is you are correct....we did fly with one system or the other off as the control switch gave you a choice of each system off or both "On". It was with the Aux system off the controls got heavy. With the "Primary" system "Off" the controls just felt a bit sloppy.
I do not recall any Hydraulic failures during normal flight operations as the old girls were very reliable.
Hi SAS, just picking up on your comment about flying the S58T with both hydraulics off. If you did this there must have been something wrong with the ship because the electrical switches are so wired that it is not possible to turn off both systems at once. Having observed the feedback through the cyclic when starting the rotor without the electrical ground hydraulic pump running gives an indication of the forces at play here and I seriously doubt you could control the ship in flight with both systems off. You're right about the "weight" of the controls when Aux hydraulics are off, they are very heavy.
oleary
28th Jun 2016, 06:44
You cannot fly either the 58 or the 61 with "no hydraulics", or the 55 for that matter.
Part of your pre take-off check (as an earlier poster suggested) is that you check to insure that you cannot turn both hydraulics systems off at the same time.
This actually happened to me one time during the pre takeoff checks on a 61.
Finally, "Aux off " in a Sikorsky ain't that big a deal.