Go Back  PPRuNe Forums > Aircrew Forums > Rotorheads
Reload this Page >

Jammed Controls - Instances?

Rotorheads A haven for helicopter professionals to discuss the things that affect them

Jammed Controls - Instances?

Old 13th Jun 2020, 21:24
  #1 (permalink)  
Thread Starter
 
Join Date: Jul 2010
Location: Brisbane
Posts: 32
Jammed Controls - Instances?

Jammed Cyclic
Jammed Collective
Jammed Pedals

Does anyone have any first or second hand knowledge of a jammed control event? What happened and how was the helicopter recovered?
Or links to accident investigations.

I'm aware of the S-61 in the UK, 2018 with a seized swashplate on takeoff but not of any other recent ones.
In the process of updating our training notes and would love to include some relevant case studies.

Focusing more on finding actual jammed control situations rather than YCE due to tail rotor driveshaft failures or broken pitch control links etc. Forum search didn't turn up much.
Thanks in advance!

Mick Cullen is offline  
Old 13th Jun 2020, 23:41
  #2 (permalink)  
 
Join Date: Sep 2002
Location: Great South East, tired and retired
Posts: 2,821
I had a collective stuck full down on an AS350 during an auto, but that was due to a poorly designed collective lock.

Yes, it is possible to land off an auto without using collective and without damaging the aircraft. Thank you, AeroSplatterall.
Ascend Charlie is offline  
Old 14th Jun 2020, 00:11
  #3 (permalink)  
 
Join Date: Apr 2014
Location: At work (Often)
Posts: 19
MD500 Collective refused to go down in straight and level attitude. Pilot seat cushion base had been misaligned slightly on velcro tape, the seat base metal frame allowed the collective to go up but caught going downward. Passenger was able to pull cushion back across when pilot lifted his arse.

Last edited by Falcon Al; 14th Jun 2020 at 02:02.
Falcon Al is offline  
Old 14th Jun 2020, 01:07
  #4 (permalink)  
 
Join Date: Dec 2010
Location: downunder
Posts: 121
Well monetarily jammed; when taking off from an elevated pinnacle pad with all doors off in R44 and the 13 yr old girl in pax seat gets a fright and levitates off the seat and lands on top of my arm and the collective. seat belt made no difference. Good thing she was light and i was sufficiently adrenaline fueled to levitate her back to her correct spot, if we hadn't been on a pinnacle it would have ended in tears. With a note to always be suspicious of teenage children, and the aircraft in the hangar, an EMS ship starts doing a search pattern overhead my house I realize she had also set of the EPIRB button in front of and under the collective. So they land and I explain it all and they have a coffee and go, taxpayers dollars in action.
Back in 1985 had a collective on a R22 jam from mid way to full up but happily it would go all the way down, something to do with incorrectly rigged bungee cord in there somewhere.
as350nut is offline  
Old 14th Jun 2020, 06:54
  #5 (permalink)  
 
Join Date: May 2001
Location: Escrick York england
Posts: 1,558
Originally Posted by Mick Cullen View Post
Jammed Cyclic
Jammed Collective
Jammed Pedals

Does anyone have any first or second hand knowledge of a jammed control event? What happened and how was the helicopter recovered?
Or links to accident investigations.

I'm aware of the S-61 in the UK, 2018 with a seized swashplate on takeoff but not of any other recent ones.
In the process of updating our training notes and would love to include some relevant case studies.

Focusing more on finding actual jammed control situations rather than YCE due to tail rotor driveshaft failures or broken pitch control links etc. Forum search didn't turn up much.
Thanks in advance!
many years ago in a enstrom 280 the sky map Gps came unstuck from the windscreen and wedged behind the pedals and the windscreen
and I couldn’t get to it to move it
luckily the pedals were straight and a safe landing was made
md 600 driver is offline  
Old 14th Jun 2020, 07:30
  #6 (permalink)  
 
Join Date: Apr 2007
Location: Out there
Posts: 282
Had the throttle jammed wide open in a 300cbi when I had about 300 hrs total and about 10 on type. Nothing in the FM for that one!
Evil Twin is offline  
Old 14th Jun 2020, 07:47
  #7 (permalink)  
 
Join Date: Sep 2002
Location: Great South East, tired and retired
Posts: 2,821
Evil, was there no mechanical link between the collective correlator and the throttle like in the R22?

Could you switch one magneto off to get a rev drop to reduce power?
Ascend Charlie is offline  
Old 14th Jun 2020, 09:17
  #8 (permalink)  
 
Join Date: Feb 2000
Location: UK
Posts: 1,292
Not jammed, but associated problem. Southern UK S&R helo Flt Cdr was large and muscular (known as 'Punch-up' P.....) Helos were Whirlwind 10s with floor mounted rotary friction adjusters for the control column. Punch-up used to insist on flying with these frictions fully tightened - "gives it a bit of 'feel' . He was duty First standby one day when the 'trapper' arrived unexpectedly. Said 'trapper' was authorised for a bit of 'hands-on' around the airfield in the standby aircraft. All was well until lift-off!! The subsequent manouevres were unusual as franfic attempts were made to translate, maintain yaw control and reduce frictions by applying feet to rotary knobs. Control and calm was eventually restored but blood pressure probably remained high for a while!!
Cornish Jack is offline  
Old 14th Jun 2020, 09:35
  #9 (permalink)  
 
Join Date: Mar 2001
Location: Longitude Zero
Posts: 62
I had a cyclic control restriction in a Westland Scout. Luckily, the restriction manifested itself during the hover check after takeoff as a solid restriction to aft cyclic movement. I landed, lifted to the hover very cautiously and found the control restriction to be still there. I shut down the aircraft and put it u/S.
A subsequent investigation revealed that a riveting mandrel had become wedged in the control bellcrank at the lower end of the cyclic. Opinion was, it had probably been rattling around down there since the aircraft was built.
pedroalpha is offline  
Old 14th Jun 2020, 11:23
  #10 (permalink)  
 
Join Date: Aug 2013
Location: Europe
Posts: 131
#1 was to blame on me - heavy AS 350 takin a too fast and too tight turn - jack stall - lower collective, etc. - all good.

#2 I was picking up a pilot who delivered a customer aircraft. I was in a HU300 with dual controls. On the return flight we had to refuel on the way. Comming to the fuel station i wanted to stop and land from a hover, but comming into the hover I couldn´t stop the aircraft spinning although applying "full" pedal. Just made it away from the fuel point an closed the throttle over a bit of grass. Turned out the other guy had placed his bag of cleaning material between windshield and dual pedals so a part of that stuff restricted the pedals from full travel. - There were a few "friendly" words afterwards. But I had to blame me as well because of not noticing the bag there earlier.
evil7 is offline  
Old 14th Jun 2020, 12:03
  #11 (permalink)  
 
Join Date: Apr 2007
Location: Out there
Posts: 282
Originally Posted by Ascend Charlie View Post
Evil, was there no mechanical link between the collective correlator and the throttle like in the R22?

Could you switch one magneto off to get a rev drop to reduce power?
There was a *mandatory* AD as I recall that was never completed on the airframe that had in big red words along the lines off ‘failure to comply may result in a condition that can lead to fatalities’ . Had to do with a bell crank at the base of the collective, as you rolled full throttle the bell crank moved past the plastic cover over the control rods between the seats And couldn’t return. Had my bucket not been completely full I could possibly have tried the mag method. However, there were a number of other things going on at the time including feedback through the comms due to electrical issues. It was a post maintenance test flight, the aircraft having just been rebuilt after a crash having been flown until it ran out of fuel. Not by me I might add!
Evil Twin is offline  
Old 14th Jun 2020, 12:31
  #12 (permalink)  
 
Join Date: May 2001
Location: Escrick York england
Posts: 1,558
Originally Posted by Ascend Charlie View Post
Evil, was there no mechanical link between the collective correlator and the throttle like in the R22?

Could you switch one magneto off to get a rev drop to reduce power?
could t you just land then cut the fuel
md 600 driver is offline  
Old 14th Jun 2020, 14:34
  #13 (permalink)  
 
Join Date: Dec 2014
Location: Africa
Posts: 370
Originally Posted by md 600 driver View Post
could t you just land then cut the fuel
Maybe the other way round?

if your throttle is open more than needed for IGE hover you will never land.
Hot and Hi is offline  
Old 14th Jun 2020, 15:28
  #14 (permalink)  
 
Join Date: Oct 2006
Location: USA
Posts: 373
Originally Posted by Mick Cullen View Post
Does anyone have any first or second hand knowledge of a jammed control event? What happened and how was the helicopter recovered?
Then there were the BO105 hydraulic pack issues. Here's two. The mis-matched SYS1/SYS2 switch-over links and the infamous "SYS1 spool valve jam due to FOD in the fluid". Both caused a hydraulic lock of the flight controls. The 1st aircraft was performing a "block test" when it jammed. Fortunately the aircraft was on the ground. Had it been flying and a microswitch had caused the switchover, who knows what would have happened. On the 2nd jam, the aircraft returned fine after a lawn dart dive toward the ground, but the look on the their faces was much more "interesting" than in the 1st case. I believe, the Hyd Pack switch-over inspection came from this incident as well, but could be mistaken.
wrench1 is offline  
Old 14th Jun 2020, 16:08
  #15 (permalink)  
 
Join Date: Apr 2017
Location: England
Posts: 80
Pootling along in the South West of England in a Wessex 5 when the rudder pedals locked. I disengaged the ASE but no change. I thought about switching off the hydraulics in turn but thought, no. I did a straight in approach to St Mawgan and ran on at around 80 knots, turned off the runway into dispersal using brakes and shut down on the run in. Re-started - problem gone...............never did find out what happened.
Georg1na is offline  
Old 14th Jun 2020, 16:21
  #16 (permalink)  
 
Join Date: Sep 2003
Location: Redding CA, or on a fire somewhere
Posts: 1,782
My incident occurred in a B2 Astar on a tour with six passengers on board. I first realized the problem coming out of an out of ground effect hover. To this day I still get confused as to whether you call it stuck left or right---basically I had about an inch and a half of left forward pedal, and was not able to push right pedal. I had the non power pedal forward. Ultimately we found the flexible ball control cable had frayed inside the plastic sheath. So as I pushed left pedal, the cable would slide freely inside the sheath, when I pushed right --- the frayed cable dug into the sheath and would not slide. Biggest thing to remember—FLY THE AIRCRAFT. I elected to fly back to the nearest airport with crash rescue facilities----not pessimistic, just stacking the odds in my favor, plus it gave me 30 minutes of transit time to figure it out in my head. Unfortunately for me---I used to switch between a 206 and an Astar frequently---the previous flight less than an hour prior to this was in the Bell---hence I do not like to say stuck left/right but try to think of it as power and non power pedal. Also, the company I worked for did NOT provide factory training, I had never done this procedure in the aircraft---read about it once--- and in fact my annual Astar training consisted of 30 minutes flying with the owner, who flew on average about 30 hours a year. (Welcome to Hawaii !---although to be fair---there are some decent operators out there). I told my passengers everything, (was later chastised by the owner---should have kept my mouth shut---I no longer fly in Hawaii ! !), I felt they were entitled to know what was going on.



For better or worse, I elected to attempt a shallow approach to a run on landing. I had enough fuel for about an hour, so I was in no rush. The wind sock was spinning on the pole, so therefore no wind. I picked the longest runway---as the speed approached about 20 kts, the aircraft started slowly spinning left, and I did a go around without pulling power till I got some more airspeed and chose a different runway. This attempt, same thing, another go around---did not pull power till I got some speed. I was starting to think that if this next attempt did not work---I would cut the engine and do an auto. This time the aircraft started spinning faster, my gut reaction was to go around, but I started pulling power----WRONG, this increased the spin violently, instinct, gut reaction, luck and the voice in my head said CUT POWER----which I half did. I got the FFCL out of the flight gate and about half way back to idle, the earth had stop spinning and I was about 10 feet up, drifting slowly forward and descending slowly, with 3 fire trucks about 100 feet in front of me. I let the aircraft settle to the ground, shut it down, and realized that adrenalin is really brown!!!!!!! I personally was not happy the way it turned out---I felt I should have nailed it on the first attempt, I should NOT have let the aircraft spin, but I am somewhat of a perfectionist, and I need to live with that. That being said, No damage to the aircraft, one passenger had passed out and was given medical attention on scene, the rest were all fine, I spilled my coffee on the runway and had to beg a soda from one of the firefighters!!!!



What did I learn?
  1. FLY THE AIRCRAFT.
  2. As stated above do not refer to this as stuck left/right, it gets too confusing when switching aircraft types.
  3. Take your time; make as many approaches as needed.
  4. No matter what anyone says—there is no text book way to do it.
  5. I did not do the “text book” procedure—but it worked.
  6. If you all walk away from it---you did good, learn and move on.


One more side note; The company did not initially refund the passengers their money until a few months later one of them asked for a copy of the NTSB report we filed as it came under NTSB 830.5 (a) (1) ----guess what---company did not file one, make sure one gets filed---you could be liable if not.
Gordy is online now  
Old 14th Jun 2020, 16:44
  #17 (permalink)  
 
Join Date: Dec 2006
Location: yes
Posts: 230
You may find the following NTSB accident reports interesting, they are similar to, but not necessarily what I would call “jammed controls”:

LAX04LA254 - While performing a maintenance check flight, the collective down lock engaged, which resulted in an uncontrolled descent and collision with terrain.

NYC97LA058 - When the pilot raised the collective, the helicopter lifted about 2 to 4 feet above the ground, and then began to roll left. The pilot attempted to correct for the left roll; however, the helicopter did not respond and the main rotor blades struck the ground.

The following 2 accidents are an apparent jamming of controls due to incorrect configuration of the helicopter hydraulic system:

CEN14IA329 - Immediately after takeoff, the helicopter started a counter-clockwise yaw. The pilot stated that the anti-torque pedals were locked in the neutral position and felt jammed.

CEN14FA193 - The pilot reported that the (antitorque) pedals felt jammed or locked in the neutral position.

JimEli is offline  
Old 14th Jun 2020, 19:07
  #18 (permalink)  
 
Join Date: Dec 2017
Location: EU
Posts: 34
I read an accident report from Ireland (I think) where the pilots mobile phone slipped down underneath the cabin floor and jammed the pedals on an R44. The pilot performed a run on landing.

I can’t find the report anymore but i remember it showing an interesting picture of the phone jamming the pedals.

If anyone is familiar please post the report
TRENT210 is offline  
Old 14th Jun 2020, 20:30
  #19 (permalink)  
 
Join Date: Dec 2006
Location: yes
Posts: 230
Originally Posted by Gordy View Post
...
What did I learn?
  1. FLY THE AIRCRAFT.
  2. As stated above do not refer to this as stuck left/right, it gets too confusing when switching aircraft types.
  3. Take your time; make as many approaches as needed.
  4. No matter what anyone says—there is no text book way to do it.
  5. I did not do the “text book” procedure—but it worked.
  6. If you all walk away from it---you did good, learn and move on.
As stated above do not refer to this as stuck left/right, it gets too confusing when switching aircraft types....
Wow, thank you for sharing. Clearly substandard 135 aircraft ground and flight training. While I agree with your conclusions #1, 2 and 3, I differ with the others. There is a textbook method. In fact, its fully explained and located in the emergency procedure section of the RFM. It should have been covered in training. I believe any professional pilot would have at least studied it and they certainly would refer to it when necessary. May your good fortune always hold.

Last edited by JimEli; 14th Jun 2020 at 22:22. Reason: fixed incorrect quote
JimEli is offline  
Old 14th Jun 2020, 22:10
  #20 (permalink)  
 
Join Date: Dec 2013
Location: UK
Age: 76
Posts: 191
Sullom Voe to Aberdeen in a Bell 214ST just after the Piper Alpha disaster, so 1988. About 10 minutes after take off the cyclic was found to have jammed in roll with about 3 degrees roll movement to starboard and 5 degrees to port. Diverted to Wick with all turns to the right so we could pick the bank up with the greater movement of the left cyclic. Did a running landing. On restart after an engineer arrived from Aberdeen the fault had disappeared. After all this time my memory deserts me as to what the possible causes were.

Also back in the 70's on a Bo105D the hinged cyclic lock arm fell down and briefly locked the cyclic.
Democritus is offline  

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information

Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.