ADVrider

Go Back   ADVrider > Fluff > Shiny things
User Name
Password
Register Inmates Photos Site Rules Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Rating: Thread Rating: 105 votes, 4.89 average. Display Modes
Old 02-14-2013, 12:00 AM   #5716
jdgretz
Looking for new places
 
jdgretz's Avatar
 
Joined: Apr 2009
Location: Canoga Park - A great place to live work and shop
Oddometer: 914
Quote:
Originally Posted by Shadow10 View Post
Can someone with knowledge of such things give us a bit more info on the condition the pilot described leading to the crash?
Sounds like a hydraulics hard over. Basically the valves on the hydraulics controls ceased functioning and jammed the controls. Sometimes recycling the on/off switch for the hydraulic control system will unstick the pump/valves but you do need a couple of seconds to do that. If that does not work, you can try pulling the circuit breaker and punching it back in. If neither of those work, you turn off the system, pull the circuit breaker and both pilots try to wrestle the system into some sort of flyable configuration. The Cobra has an emergency accumulator/hydraulic pump that can be turned on to provide hydraulic power for a very limited time. It is normally used only on final approach as you don't get much use out of it, so it is a last resort sort of thing.

Cobras also have a stability augmentation system that the old UH-1 does not have which also complicates matters. See http://www.liberatedmanuals.com/TM-1-1520-236-CL.pdf or TM 55-1520-236-10 page 322 for more information.

A simple hydraulics failure as opposed to the hard over is much easier to deal with. In the simple situation, the pump just quits pumping but everything else works - no closed valves, etc. Not a lot of fun, but flyable and pilots do train on those maneuvers.

I know many of the folks at the Army Aviation Heritage Foundation (flew with some of them as well back in they day) and all their pilots are very experienced and capable.

jdg
__________________
'07 Norge - the fast red one
'03 Honda Shadow 750 - Rocky
'99 Honda Helix - Little Zippy
'76 Honda CJ360T
jdgretz is offline   Reply With Quote
Old 02-18-2013, 01:22 AM   #5717
GunshipDriver
Adventure in Iraq '07!
 
GunshipDriver's Avatar
 
Joined: Aug 2005
Location: Inland Empire
Oddometer: 464
Reversals at low altitudes and low airspeeds are never a good idea imo. I know of other H-1s that have been planted by highly trained and capable pilots. It will be interesting to note how the AMB investigation goes in regards to what they do or don't find in their further examination of the mechanical system to include hydraulics and scas.
__________________
The Stable: '03 KTM 640 Adv / '08 KTM 530 EXCR / '05 BMW R1200RT / *looking for an Elise/Exige*
Former Rides: 06 950 SM / '04 950 Adv / '04 RSVR Factory / '04 625 SMC / '03 XR650R / '98 Tiger / '99 R1 / '97 ZX-6R
GunshipDriver is offline   Reply With Quote
Old 02-18-2013, 01:43 PM   #5718
Elvis70
No speed traps in the sky
 
Elvis70's Avatar
 
Joined: May 2008
Location: Fayetteville, AR
Oddometer: 5,053
Sorry about the loss of your crew mate and friend.
__________________
I'll tape it to the handlebars, it's just logic George! If your hand is broken, you tape it to the bars! - Evil Knievel's reply to George Hamiliton's question, "How will you jump with a broken hand?".
Elvis70 is offline   Reply With Quote
Old 02-18-2013, 08:53 PM   #5719
Vagabond_Explorer
Relax_Unwind_Chill
 
Joined: Aug 2012
Location: Southern Cross Land
Oddometer: 126
Quote:
Originally Posted by jdgretz View Post
Sounds like a hydraulics hard over. Basically the valves on the hydraulics controls ceased functioning and jammed the controls. Sometimes recycling the on/off switch for the hydraulic control system will unstick the pump/valves but you do need a couple of seconds to do that. If that does not work, you can try pulling the circuit breaker and punching it back in. If neither of those work, you turn off the system, pull the circuit breaker and both pilots try to wrestle the system into some sort of flyable configuration. The Cobra has an emergency accumulator/hydraulic pump that can be turned on to provide hydraulic power for a very limited time. It is normally used only on final approach as you don't get much use out of it, so it is a last resort sort of thing.

Cobras also have a stability augmentation system that the old UH-1 does not have which also complicates matters. See http://www.liberatedmanuals.com/TM-1-1520-236-CL.pdf or TM 55-1520-236-10 page 322 for more information.

A simple hydraulics failure as opposed to the hard over is much easier to deal with. In the simple situation, the pump just quits pumping but everything else works - no closed valves, etc. Not a lot of fun, but flyable and pilots do train on those maneuvers.

I know many of the folks at the Army Aviation Heritage Foundation (flew with some of them as well back in they day) and all their pilots are very experienced and capable.

jdg
I looked carefully at the video - it doesn't look like the pilot had a hydraulics failure. It looked like he was in perfect control of the attitude right until the crash. However, I am just speculating. To me, it looked like he misjudged the height - however I am willing to be corrected. jdgretyz - are you talking about recycling the SACS (at the bottom of the cyclic grip) rather the the actual hydraulic system? As you know, Cobras will fly without the SACS but there's less stability. Just wondering...
Vagabond_Explorer is offline   Reply With Quote
Old 02-19-2013, 12:39 PM   #5720
fireflyr
Gnarly Adventurer
 
fireflyr's Avatar
 
Joined: Mar 2008
Location: Keene, California
Oddometer: 412
Quote:
Originally Posted by GunshipDriver View Post
Reversals at low altitudes and low airspeeds are never a good idea imo. I know of other H-1s that have been planted by highly trained and capable pilots. It will be interesting to note how the AMB investigation goes in regards to what they do or don't find in their further examination of the mechanical system to include hydraulics and scas.
I agree. I doubt they will find anything wrong with the hydraulic / flight control system. I had a irreversible valve failure in a 205A1++ while in a left turn and it tried to roll over on its back. The cyclic locked to the left (where it had been displaced for the turn) and I was only able to move it when the reservoir on the roof replenished the servo. I got the cyclic centered and then turned off the hydraulic switch and landed the aircraft in a field. I've had 4 complete hydraulic failures over the years and never crashed.

In my opinion, he just attempted the maneuver too close to the ground.

Disclaimer: We all know what opinions are worth.
__________________
2013 Moto Guzzi V7 Racer, #347
2004 XR400R Dual Sport, Baja Designs kit
2005 TTR 125 (son's)
1967 & 1971 Honda Trail 90s
fireflyr is offline   Reply With Quote
Old 02-19-2013, 03:47 PM   #5721
jdgretz
Looking for new places
 
jdgretz's Avatar
 
Joined: Apr 2009
Location: Canoga Park - A great place to live work and shop
Oddometer: 914
Quote:
Originally Posted by Vagabond_Explorer View Post
I looked carefully at the video - it doesn't look like the pilot had a hydraulics failure. It looked like he was in perfect control of the attitude right until the crash. However, I am just speculating. To me, it looked like he misjudged the height - however I am willing to be corrected. jdgretyz - are you talking about recycling the SACS (at the bottom of the cyclic grip) rather the the actual hydraulic system? As you know, Cobras will fly without the SACS but there's less stability. Just wondering...
No, actually hitting the circuit breakers for the hydraulics control system. Sometimes recycling the power to the system will get the valves or pump working again.

The emergency procedures called out include:

  • Emergency Hydraulic Pump Switch - OFF (pilot and gunner)
  • Hydraulic Control Circuit Breaker - IN
  • SCAS - Disengage appropriate Channel
    • System 1 - Yaw
    • System 2 - Roll and Pitch
  • Emergency Hydraulic Pump Switch - On for final approach
The above is for a single channel failure. For a dual channel failure, you shut the whole system down using either the SCAS button or the SCAS Control Panel.


You should have circuit breakers for Hydraulic Control (main pump power), SCAS Power and Emergency Hydraulic Pump Power on the Essential Buss Circuit Breaker Panel as well as SCAS Power on the 115v.


If the standard emergency procedures don't work, recycling the main SCAS power will sometimes work. Given enough time, altitude and airspeed, you try them all. Hopefully something will knock some sense back into the hydraulic system.


Remember - punching the button on the cyclic will disengage the entire SCAS system which then needs to be re-engaged using the switches on the SCAS Control Panel.


I spent a bunch more hours in the UH-1 than the AH-1 and did my test pilot training in the UH-1 so my thinking runs that way first. Speaking of hydraulics rather than SCAS is a bit easier for someone who is not familiar with the peculiarities of the Cobra.


I too am curious to see what the tear down analysis of the hydraulic system show. Did he misjudge or did the hydraulics lock up? His initial statement to the board seems to indicate a failure of some sort.


jdg
__________________
'07 Norge - the fast red one
'03 Honda Shadow 750 - Rocky
'99 Honda Helix - Little Zippy
'76 Honda CJ360T
jdgretz is offline   Reply With Quote
Old 02-22-2013, 12:45 PM   #5722
EvilGenius
1.5 Finger Discount
 
EvilGenius's Avatar
 
Joined: Apr 2007
Location: DFW, Texas
Oddometer: 20,305
The new EC 175 just flew in to start off the US demo tour.



(Not my pic)

Quieter than I expected, short than I expected too.
__________________
"Try turning that burn into torque. Then we're getting somewhere. Riding the potato to work seems quite impractical." - anotherguy

"Never bring a Nerf gun to a shovel fight." - My Brother
EvilGenius is offline   Reply With Quote
Old 02-23-2013, 12:49 AM   #5723
Vagabond_Explorer
Relax_Unwind_Chill
 
Joined: Aug 2012
Location: Southern Cross Land
Oddometer: 126
Wicked

Quote:
Originally Posted by EvilGenius View Post
The new EC 175 just flew in to start off the US demo tour.
What is the interior like? Sometimes I feel like the cheapest Japanese cars have better quality than EC's interior. The AS350 has a plastic roof that caves in when the aircraft is parked outside in 100 deg F heat. The plastic that covers the pillar between the 2 windscreen perspex sags till it hits the instrument panel when exposed to direct sunlight.

The new energy absorbing seats are more uncomfortable than a wooden bar stool in a cheap hotel in Bangkok. At the hint of the smallest amount of rain, the windscreens or roof perspex or windows or chin bubbles lets water in.

They are fantastic powerful machines. If only Bell did the maintenance and any Jap car companies did the interior.

Just some personal experiences on EC's 350's, 120's, 135's, 130's, 355's, 145's, 117's. etc.
Vagabond_Explorer is offline   Reply With Quote
Old 02-23-2013, 09:45 AM   #5724
EvilGenius
1.5 Finger Discount
 
EvilGenius's Avatar
 
Joined: Apr 2007
Location: DFW, Texas
Oddometer: 20,305
Quote:
Originally Posted by Vagabond_Explorer View Post
What is the interior like? Sometimes I feel like the cheapest Japanese cars have better quality than EC's interior. The AS350 has a plastic roof that caves in when the aircraft is parked outside in 100 deg F heat. The plastic that covers the pillar between the 2 windscreen perspex sags till it hits the instrument panel when exposed to direct sunlight.

The new energy absorbing seats are more uncomfortable than a wooden bar stool in a cheap hotel in Bangkok. At the hint of the smallest amount of rain, the windscreens or roof perspex or windows or chin bubbles lets water in.

They are fantastic powerful machines. If only Bell did the maintenance and any Jap car companies did the interior.

Just some personal experiences on EC's 350's, 120's, 135's, 130's, 355's, 145's, 117's. etc.
I couldn't get close enough to see inside so I couldn't tell ya. Since it's a demo craft I wouldn't be surprised if it was really nice. We do have the capability of putting in really nice seats and interiors, but those are pricey and not much of a concern for most customers I do know what you mean by the regular seats though.

Dunno what to tell you about the drooping panels. I noticed they're a little thin when I used to prep them for shipping, but some genius though it was a good idea to face our hangar south and during the summer where it routinely hits 100+ for months during that time and I haven't heard of those issues.

I agree about the maintenance. I love disecting tech pubs that are written in two different countries whose languages I don't speak and have almost totally opposite ideologies about how to setup manuals and what constitutes relevant information.
__________________
"Try turning that burn into torque. Then we're getting somewhere. Riding the potato to work seems quite impractical." - anotherguy

"Never bring a Nerf gun to a shovel fight." - My Brother
EvilGenius is offline   Reply With Quote
Old 02-25-2013, 02:11 AM   #5725
GunshipDriver
Adventure in Iraq '07!
 
GunshipDriver's Avatar
 
Joined: Aug 2005
Location: Inland Empire
Oddometer: 464
you can take this with a grain of salt.. but reversals at 100' AGL are plenty doable.. but I would reccomend starting with 100-120 KIAS and executing a health pop when trading the airspeed (kinetic engergy) for altitude (potential energy) and then back on the descent when speeding back up. the one caveat I would mention though is being keenly aware of any strange crosswinds or the such which could make for a slightly uncomfortable situation as anytime you are closer to the ground there is that much less room for error.
__________________
The Stable: '03 KTM 640 Adv / '08 KTM 530 EXCR / '05 BMW R1200RT / *looking for an Elise/Exige*
Former Rides: 06 950 SM / '04 950 Adv / '04 RSVR Factory / '04 625 SMC / '03 XR650R / '98 Tiger / '99 R1 / '97 ZX-6R
GunshipDriver is offline   Reply With Quote
Old 02-25-2013, 09:25 AM   #5726
jdgretz
Looking for new places
 
jdgretz's Avatar
 
Joined: Apr 2009
Location: Canoga Park - A great place to live work and shop
Oddometer: 914
Quote:
Originally Posted by GunshipDriver View Post
you can take this with a grain of salt.. but reversals at 100' AGL are plenty doable.. but I would reccomend starting with 100-120 KIAS and executing a health pop when trading the airspeed (kinetic engergy) for altitude (potential energy) and then back on the descent when speeding back up. the one caveat I would mention though is being keenly aware of any strange crosswinds or the such which could make for a slightly uncomfortable situation as anytime you are closer to the ground there is that much less room for error.
Of course they are doable - and relatively safely - considering you're in the red area for autos most of the time. Hell, the number of them performed in Nam without incident is testament to that.

As you say, you just have to be really aware of everything.

jdg
__________________
'07 Norge - the fast red one
'03 Honda Shadow 750 - Rocky
'99 Honda Helix - Little Zippy
'76 Honda CJ360T
jdgretz is offline   Reply With Quote
Old 03-01-2013, 09:03 PM   #5727
AerialCameras
Gyrating Peacefully
 
AerialCameras's Avatar
 
Joined: Nov 2008
Location: Wekiva Springs, Florida
Oddometer: 1,893






AerialCameras is offline   Reply With Quote
Old 03-02-2013, 12:14 AM   #5728
fz6kd7
Studly Adventurer
 
Joined: Dec 2007
Location: LAS VEGAS USA
Oddometer: 730
Quote:
Originally Posted by AerialCameras View Post







Did you do any filming on the vegas strip of this one?

I seen a red white and blue one and looked like it was being
Followed by another copter looked like filming etc.. anyway it looked
Nice
fz6kd7 is offline   Reply With Quote
Old 03-02-2013, 10:59 PM   #5729
AerialCameras
Gyrating Peacefully
 
AerialCameras's Avatar
 
Joined: Nov 2008
Location: Wekiva Springs, Florida
Oddometer: 1,893
Quote:
Originally Posted by fz6kd7 View Post
Did you do any filming on the vegas strip of this one?

I seen a red white and blue one and looked like it was being
Followed by another copter looked like filming etc.. anyway it looked
Nice
Yep

AerialCameras is offline   Reply With Quote
Old 03-03-2013, 10:42 AM   #5730
fz6kd7
Studly Adventurer
 
Joined: Dec 2007
Location: LAS VEGAS USA
Oddometer: 730
I forget what day but i seen it low and south of downtown
At sunset

I think you qualify for the cool job award
fz6kd7 is offline   Reply With Quote
Reply

Share

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


Times are GMT -7.   It's 11:58 PM.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright ADVrider 2011-2014