VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics


Go Back   VAF Forums > Main > Safety
Register FAQ Members List Calendar Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 08-21-2013, 10:49 PM
heinz heinz is offline
 
Join Date: Sep 2010
Location: comox bc
Posts: 52
Default Post crash fires

Last week there was another fatal aircraft accident in my neck of the woods. A DeHaviland Beaver on floats in bad weather with six people on board crashed into the woods in a remote part of Vancouver Island. It appears that all six people survived the crash, but the pilot and one passenger died in the resultant fuel fed fire.

In the Vans RV community I personally know of three fatalities and I'm sure there are many more in both amature and small certified aircraft accidents where post crash fires have claimed lives. Not a nice way to go.

A lot of these crashes where survivable, but the major aircraft damage that resulted involved electrical components and wiring that is fractured, torn and compromised, causing shorts and arcing and fire.

In the RV community we have much expertise, skill and knowledge and are often way ahead of industry in innovation, solution and problem solving.

The problem is-----Post Crash Fires----- caused by shorted and arcing electrical wiring.

The solution is to disconnect the battery from the electrical system by incorporating a G activated switch. This could be as simple as the solid state G switch in our ELT s.

Most small aircraft have a master solenoid that is activated by providing a ground to the solenoid coil. The G switch would be connected to this terminal and in the event of a crash - say 10 Gs - would disconnect the ground connection and open the master solenoid contacts, thus removing the battery from the aircraft electrical system. ----No arcing, shorting and very likely, no post crash fire.

If there was any concern about loosing power to aircraft systems during turbulence or IFR, a simple panel mounted by pass toggle switch would solve that concern.

For some of our electronic wizards this would be a simple technical challenge that has commercial potential, but far more importantly it would save lives.

I invite comment and discussion.
Reply With Quote
  #2  
Old 08-21-2013, 11:40 PM
smiller smiller is offline
 
Join Date: Feb 2008
Location: Hillsboro, Oregon
Posts: 102
Default

Do we know that most of these postcrash fires are due to electrical shorts/sparks? Or by fuel coming into contact with hot engine/exhaust components, or metal that got hot in the process of being bent/scraped during the crash? Not having any idea myself, I would guess that the second sentence is more likely. Otherwise, I like your idea!
__________________
Shannon Miller
RV-7A Fuselage
Reply With Quote
  #3  
Old 08-21-2013, 11:55 PM
roee roee is offline
 
Join Date: Feb 2006
Location: San Diego, CA, U.S.A.
Posts: 770
Default

I share smiller's skepticism that most post-crash fires have the electrical system as the ignition source, rather than hot exhaust components, etc.

Having said that, every checklist I've ever seen for an off-airport forced landing includes turning off the master switch before touchdown. That seems like a prudent measure. That, along with turning the fuel selector valve to "off", to keep the fuel and potential ignition sources apart as much as possible.

Having said all that, designing a g-switch to disable the master relay as the OP described would not be too difficult, and could under some circumstances help if the pilot failed to turn off the master prior to impact. Still, how often the electrical system is a significant contributor to post-crash fires, I don't know.
__________________
Roee Kalinsky
San Diego, CA, U.S.A.
RV-7A under construction
www.kalinskyconsulting.com/rvproj/
Reply With Quote
  #4  
Old 08-22-2013, 12:10 AM
Andrew M's Avatar
Andrew M Andrew M is offline
 
Join Date: Aug 2006
Location: Secluded Lake,Alaska (AK49)
Posts: 359
Default Crashes

A Piper Malibu suffered a mid air around Boulder CO in the 80's. The pilot had the sense to shut the fuel off at the firewall and add full power to burn off the remainder fwf fuel. No post crash fire. He perished minutes after impact.
A Otter crashed on take off here in Alaska this summer. Two families perished in the post crash fire. The fuel is carried in the belly, same as the Beaver.
I am interested in a gizmo that will shutoff fuel at the wing/fuselage joint if the wing is torn off or some how disturbed. With the airframe fuel pump returning excess fuel, I imagine a "crash pull" handle that would isolate electrical systems, and shutoff fuel, arm fire extinguisher, activate elt and ?????
__________________
Andrew Miller
A&P, IA
-9 empennage
Wings arrived 12 JAN 13
https://plus.google.com/photos/11360...J-TuJPsmOONzQE
Reply With Quote
  #5  
Old 08-22-2013, 04:46 AM
Kahuna's Avatar
Kahuna Kahuna is offline
 
Join Date: Dec 2004
Location: Gold Hill, NC25
Posts: 2,400
Default

This is one option. Our entire team has these switches on fuel and smoke. There is nothing preventing this from being on the master switch to do it all.
http://www.vansairforce.com/communit...5&postcount=26
__________________
Kahuna
6A, S8 ,
Gold Hill, NC25
Reply With Quote
  #6  
Old 08-22-2013, 05:48 AM
rv7boy's Avatar
rv7boy rv7boy is offline
Forum Peruser
 
Join Date: Jan 2005
Location: Austinville, Alabama
Posts: 2,458
Default NASCAR Technology

I don't disagree with any of the above methods of reducing the risk of post crash fires. But I also dream of the day when aircraft fuel tanks use the same technology NASCAR uses to minimize fuel leakage when a tank is crushed. This is not nearly as big a problem in NASCAR as it once was.

This quote is from "How Stuff Works:"

"In the 1950s, NASCAR race cars used the fuel tanks from whatever street car they were based on. There were some schemes for wood reinforcements, but leaks and fires were common. Today's 22-gallon fuel tanks, also called fuel cells, have built-in safety features to limit the chance of them rupturing or exploding.

Fuel cells have a steel outer layer a­nd a hard, plastic inner layer. The fuel cell is located in the rear of the car and is held in place by four braces that keep it from flying loose during an accident. It is filled with foam, which reduces the slosh of the fuel and any chance of explosion by reducing the amount of air in the cell. If the cell does ignite internally, the foam absorbs the explosion. The car also has check valves that will shut off fuel if the engine is separated from the car."

And a little surfing yields some recent technology. Some enterprising individual should pursue adapting this technology to our RV wing tanks.

Maybe someone has already done this for RV's but I'm not aware of it. Check out this link and this link. Hmmm, they're made in Redmond, Oregon. Google maps says it's only a 3 hour drive from Redmond to Aurora, Oregon. Maybe someone can visit somebody, and we'll have a fuel bladder option soon.
__________________
Don Hull
RV-7 Wings
KDCU Pryor Field
Pilots'n Paws Pilot
N79599/ADS-B In and Out...and I like it!

?Certainly, travel is more than the seeing of sights;
it is a change that goes on, deep and permanent, in the ideas of living." Miriam Beard

Last edited by rv7boy : 08-22-2013 at 09:51 AM. Reason: Added the "HSW" quote. Added some more links.
Reply With Quote
  #7  
Old 08-22-2013, 07:50 AM
RV7Guy's Avatar
RV7Guy RV7Guy is offline
 
Join Date: Jan 2005
Location: Chandler, AZ
Posts: 2,904
Default Fire Suppression System

I'm installing a Safecraft fire suppression system in my new 7. Fire scares me more than anything.

It is only 6 lbs and is mechanical so no power needed. I feel if it is a survivable crash it might be able to put out a FWF fire before getting to the tanks. Just might give you those few seconds needed to get out.

Cheap insurance in my book.
__________________
Darwin N. Barrie
Chandler AZ
www.JDair.com
RV-7 N717EE-Flying (Sold)
RV-7 N717AZ Flying, in paint
EMS Bell 407,
Eurocopter 350 A-Star Driver
Reply With Quote
  #8  
Old 08-22-2013, 09:37 AM
rv7boy's Avatar
rv7boy rv7boy is offline
Forum Peruser
 
Join Date: Jan 2005
Location: Austinville, Alabama
Posts: 2,458
Default Where's the link?

Quote:
Originally Posted by Kahuna View Post
This is one option. Our entire team has these switches on fuel and smoke. There is nothing preventing this from being on the master switch to do it all.
http://www.vansairforce.com/communit...5&postcount=26
Mike, where is the link to the description and ordering information for the inertia activated shutoff switch? I don't see it on the above page or on the linked pages.
__________________
Don Hull
RV-7 Wings
KDCU Pryor Field
Pilots'n Paws Pilot
N79599/ADS-B In and Out...and I like it!

?Certainly, travel is more than the seeing of sights;
it is a change that goes on, deep and permanent, in the ideas of living." Miriam Beard

Last edited by rv7boy : 08-22-2013 at 09:42 AM.
Reply With Quote
  #9  
Old 08-22-2013, 09:55 AM
Mike S's Avatar
Mike S Mike S is offline
Senior Curmudgeon
 
Join Date: Sep 2005
Location: Dayton Airpark, NV A34
Posts: 15,420
Default From an old fireman.

Basics of fire. Really basic.

You need 3 things for a fire, air, fuel, and a source of ignition.

The removal of any one of these will keep a fire from happening.

The air component is something we can not eliminate.

In the case of our aircraft, the fuel is virtually always either the avgas in the tanks, or the oil in the engine-------there just is not a lot of other combustible stuff in our planes to worry about.

Lastly, the ignition component is virtually always either going to be the electrical system as stated in the OP, or the hot exhaust.

So, if you have time, and presence of mind, shut down both the fuel system and the electrical system. Not a lot that can be done about the hot exhaust.

And, dont forget to fly the plane-------the best fire prevention is to prevent the crash in the first place.
__________________
Mike Starkey
VAF 909

Rv-10, N210LM.

Flying as of 12/4/2010

Phase 1 done, 2/4/2011

Sold after 240+ wonderful hours of flight.

"Flying the airplane is more important than radioing your plight to a person on the ground incapable of understanding or doing anything about it."

Last edited by Mike S : 08-22-2013 at 09:58 AM.
Reply With Quote
  #10  
Old 08-22-2013, 10:01 AM
AndyRV7's Avatar
AndyRV7 AndyRV7 is offline
 
Join Date: Sep 2007
Location: Hudson County, NJ
Posts: 1,092
Default

Excellent discussion and something every pilot is fearful of I'm sure. Egress from an inverted RV is the thing that worries me.

One question. Does 100LL ignite by hot metal? The reason I ask, and am now ashamed to even discuss, is that I had an old '64 Buick Skylark as a kid. It had a rotten fuel line leaving the tank and there were times before I fixed it when the fuel would run onto the tail pipe and vaporize from the heat. I'm sure it was running on 87 octane. I would think 100LL would be that much more difficult to get to combust.

Just curious.
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

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

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 05:13 AM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.