Ethiopean 787 fire at Heathrow
Join Date: Jul 2013
Location: Eastern Anglia
Age: 75
Posts: 131
Likes: 0
Received 0 Likes
on
0 Posts
The Roadie
However, they add another layer of risk in the failure flowchart,
Electic
Meanwhile everybody should be aware, as it was already posted in post 581,
post 581
Karel_x posted it in post 769,
Post 769
What has not been discussed is, how they could save over 50% of weight by maintaining the same power output. Could this weight saving be on behalf of less built in safety, insulation and more risk when using 2 cells instead of 6 cells?
I don't know if it is any help, but here is the company product brochure for the Honeywell RESCU406AFN2
http://www51.honeywell.com/aero/comm...U_406_AFN2.pdf
http://www51.honeywell.com/aero/comm...U_406_AFN2.pdf
post 581
Karel_x posted it in post 769,
Post 769
What has not been discussed is, how they could save over 50% of weight by maintaining the same power output. Could this weight saving be on behalf of less built in safety, insulation and more risk when using 2 cells instead of 6 cells?
Last edited by RetiredF4; 28th Jul 2013 at 22:15.
checks for Honeywell ELTs on other model aircraft
Bloomberg is posting a story stating that Boeing "asked specific operators of 717, next-generation 737, 747-400, 767 and 777 airplanes to also inspect aircraft with fixed emergency locator transmitters, or ELTs, from Honeywell". This is described as pursuant to an AAIB recommendation.
The Bloomberg story is directly sourced to Randy Tinseth's (Boeing marketing VP) blog, which you can find easily enough, but which when updated will no longer carry this entry at the top.
The Bloomberg story is directly sourced to Randy Tinseth's (Boeing marketing VP) blog, which you can find easily enough, but which when updated will no longer carry this entry at the top.
Join Date: Jun 2010
Location: Czech Republic
Posts: 185
Likes: 0
Received 0 Likes
on
0 Posts
how they could save over 50% of weight by maintaining the same power output
Join Date: Jul 2002
Location: Ireland
Posts: 596
Likes: 0
Received 0 Likes
on
0 Posts
What has not been discussed is, how they could save over 50% of weight by maintaining the same power output.
http://www.pprune.org/rumours-news/5...ml#post7964412
Join Date: Jun 2009
Location: NNW of Antipodes
Age: 81
Posts: 1,330
Received 0 Likes
on
0 Posts
@ SoS
Following from Honeywell -
Note the 12 year battery life.
I believe there are 2 packs comprising 4 cells in each and most likely of the Li-MnO2 type.
Following from Honeywell -
Specifications (RESCU 406 AFN2)
MTBF 100,000 hours (estimated)
Certifications Approved by Boeing, Airbus, Dassault, FAA
RF Power 100 mW 121.5 MHz, 5 watts (406 MHz)
Battery Service Life 12 Years
Compatibility Backwards compatible with RESCU 406 AFN
MTBF 100,000 hours (estimated)
Certifications Approved by Boeing, Airbus, Dassault, FAA
RF Power 100 mW 121.5 MHz, 5 watts (406 MHz)
Battery Service Life 12 Years
Compatibility Backwards compatible with RESCU 406 AFN
I believe there are 2 packs comprising 4 cells in each and most likely of the Li-MnO2 type.
Can anybody tell me the cost per life saved by fixed ELTs in heavy transport aircraft? My strong suspicion is that not a SINGLE life has been saved and the cumulative cost over the last thirty years probably in the hundreds of millions of dollars. As well as the cost, the PROVEN increase in risk must be taken into account.
Just because a thing CAN be done doesn't mean that it is sensible that it should be done*.
In my view fixed ELTs MIGHT be justifiable in aircraft up to light twins but that is all.
*In the mid seventies the head of training, on F27, of a national carrier, carried out a GA from 1500 ft on final on glide path below all cloud, with gear down and locked**, after there was an explosion in one wheel well. He could do it, but should he have? Nah.
** There were still three greens after the explosion. That's all one needs to land an F27 on 10000'.
Just because a thing CAN be done doesn't mean that it is sensible that it should be done*.
In my view fixed ELTs MIGHT be justifiable in aircraft up to light twins but that is all.
*In the mid seventies the head of training, on F27, of a national carrier, carried out a GA from 1500 ft on final on glide path below all cloud, with gear down and locked**, after there was an explosion in one wheel well. He could do it, but should he have? Nah.
** There were still three greens after the explosion. That's all one needs to land an F27 on 10000'.
Join Date: Jul 2002
Location: Ireland
Posts: 596
Likes: 0
Received 0 Likes
on
0 Posts
mm43
Thanks for that.
There seems to be a number of data sheets around giving different information.
I'm still struggling to understand how a greatly reduced number of cells can provide the same amount of power or even more, using the same Li-MnO2 chemistry.
There seems to be a number of data sheets around giving different information.
I'm still struggling to understand how a greatly reduced number of cells can provide the same amount of power or even more, using the same Li-MnO2 chemistry.
Join Date: Jul 2013
Location: Eastern Anglia
Age: 75
Posts: 131
Likes: 0
Received 0 Likes
on
0 Posts
I'm still struggling to understand how a greatly reduced number of cells can provide the same amount of power or even more, using the same Li-MnO2 chemistry
As others have said too, we don't know how long the transmissions have to last when used in anger perhaps the MKI battery was over specified in that respect?
Join Date: Aug 2000
Location: EGGW
Posts: 2,112
Likes: 0
Received 0 Likes
on
0 Posts
mm43
The 12 year life for the battery is the same for the portable RESCU 406 ELT that Honeywell makes, which is also fitted to some B787 aircraft.
My guess would be the same type of battery, but l am not in a position to check at this time.
The batteries are replaced however at 10 years as per the MPD for the fixed ELT.
It is the same interval also for the portable ELT, which aligns with the second 5 year off wing inspections.
My guess would be the same type of battery, but l am not in a position to check at this time.
The batteries are replaced however at 10 years as per the MPD for the fixed ELT.
It is the same interval also for the portable ELT, which aligns with the second 5 year off wing inspections.
Can anybody tell me the cost per life saved by fixed ELTs in heavy transport aircraft? My strong suspicion is that not a SINGLE life has been saved and the cumulative cost over the last thirty years probably in the hundreds of millions of dollars. As well as the cost, the PROVEN increase in risk must be taken into account.
Just because a thing CAN be done doesn't mean that it is sensible that it should be done*.
In my view fixed ELTs MIGHT be justifiable in aircraft up to light twins but that is all.
Just because a thing CAN be done doesn't mean that it is sensible that it should be done*.
In my view fixed ELTs MIGHT be justifiable in aircraft up to light twins but that is all.
As you suppose, the answer is NIL!
See my posts a few pages back, the in-service failure rate in accidents for fixed ELT is better (or worse)than 95%, or 100% in water.
They are simply not justified on any aircraft. The Australian research and results on the subject is very clear.
Fixed ELT are an utter waste of money, without regard to any additional risks they may introduce.
What other piece of equipment with a 95%+ failure rate is tolerated on an aircraft??
Tootle pip!!
Last edited by LeadSled; 29th Jul 2013 at 08:51.
787 Chief Project Engineer at Boeing, Mike Sinnett, sidelined :
Boeing changes chief 787 engineer in management shuffle | Reuters
Boeing changes chief 787 engineer in management shuffle | Reuters
Join Date: Jul 2002
Location: Ireland
Posts: 596
Likes: 0
Received 0 Likes
on
0 Posts
fenland787
Bigger capacity cells,
If the same, or greater power can be derived from a 60% smaller volume of cells, then the energy density of those cells must be more than double.
Energy efficiency savings gained by better circuit design would be somewhere around 5-10%, and only then if the mark one electronics were very inefficient to start with.
Join Date: Mar 2013
Location: Siliconia
Age: 63
Posts: 44
Likes: 0
Received 0 Likes
on
0 Posts
A further thought on battery size and life...
The monthly system self-test described in the data sheet is declared as having a total duration of 5 seconds (unchanged between unit types), elsewhere the data sheet states "Enhanced ... and self test".
There is a merit in keeping the outside observable maintenance procedures unchanged, to eliminate possible adverse risks of forward and backwards compatibility.
A reduced battery size can be speculated, based upon a system self-test using less power per usage (month), by enhancement to the test sequences and better test result data integration.
The monthly system self-test described in the data sheet is declared as having a total duration of 5 seconds (unchanged between unit types), elsewhere the data sheet states "Enhanced ... and self test".
There is a merit in keeping the outside observable maintenance procedures unchanged, to eliminate possible adverse risks of forward and backwards compatibility.
A reduced battery size can be speculated, based upon a system self-test using less power per usage (month), by enhancement to the test sequences and better test result data integration.
Join Date: Jul 2013
Location: Eastern Anglia
Age: 75
Posts: 131
Likes: 0
Received 0 Likes
on
0 Posts
If the same, or greater power can be derived from a 60% smaller volume of cells, then the energy density of those cells must be more than double.
Join Date: Jul 2013
Location: UK
Age: 68
Posts: 736
Likes: 0
Received 0 Likes
on
0 Posts
Join Date: Dec 2006
Location: Florida and wherever my laptop is
Posts: 1,350
Likes: 0
Received 0 Likes
on
0 Posts
In the Bloomberg report Boeing changes chief 787 engineer in management shuffle | Reuters
is the following throwaway line...
Obviously, a fire in another aircraft type would be of zero interest to the baying peanut gallery - but when it happened in a 787 it is suddenly worldwide news. So the various regulatory bodies only took action after the media interest?
is the following throwaway line...
Investigators traced that incident to pinched wires in an emergency beacon and regulators instructed airlines to inspect or replace the units. Since then, other reports of fires have surfaced.
Join Date: Jul 2002
Location: Ireland
Posts: 596
Likes: 0
Received 0 Likes
on
0 Posts
fenland787
Agreed, do we know the cell volume is decreased by 60% or just the housing/battery pack? Not disputing, just asking!
I wish I could find the damn jpeg as a few people have asked what the inside of the beacon looks like!
Join Date: Aug 2000
Location: EGGW
Posts: 2,112
Likes: 0
Received 0 Likes
on
0 Posts
Eclectic
Don't believe all that you read from the unreliable press.
Not all EASA supervised airlines operating the B787 have removed the fixed ELT, l know of one that is inspecting the wiring around the ELT and the outer case for signs of overheating, on a daily basis.
Not all EASA supervised airlines operating the B787 have removed the fixed ELT, l know of one that is inspecting the wiring around the ELT and the outer case for signs of overheating, on a daily basis.