Inertage des réservoirs

Bonjour à tous

Une évolution réglementaire à venir : l'inertage des réservoirs vides

Marshall Aerospace propose une solution pour les avions existants

http://www.flightglobal.com/articles/2010/04/14/340553/marshall-aerospace-talks-fuel-tank-inerting-with-757-767.html

Marshall Aerospace is in discussions with several airlines over the provision of a fuel tank inerting modification for their Boeing 757 and 767 fleets.

The UK company expects to install its modular onboard inert gas generating system (OBIGGS) on an aircraft for the first time next year, with the safety enhancement now in the design and risk-reduction phase.

"We are looking at OBIGGS solutions for the 757-200/300 and the 767-300/300ER and 400ER," says commercial inerting project manager Richard Milne. Workshop sessions have already been held with potential customers, and the company has also studied offering the enhancement for the Airbus A320.

The use of common systems and components will reduce spares demands and training requirements for airlines operating types from both manufacturers, he adds.

Marshall launched its commercial retrofit programme in response to a US Federal Aviation Administration regulation which calls for all carriers to install the safety enhancement. Approved after an investigation into the 1996 loss of a TWA 747-100 after a centre fuel tank explosion, Special Federal Aviation Regulation 88 requires half of an airline's fleet to be equipped with nitrogen fuel tank inerting equipment by 2014, and the remainder by 2017.




"We are developing a product to support the airlines to do that job," says Philip Windred, managing director of Marshall Aerospace's Technology, Products & Services business unit.

"The competitors are the original equipment manufacturers, but they are designing systems for new aircraft. We are convinced that there are significant advantages, primarily in the installation time, with not having to integrate it with the rest of the aircraft systems," he says.

The Marshall design uses air separation membrane technology, which strips out oxygen and carbon dioxide from cooled bleed air before pumping almost pure nitrogen into the ullage of a centre wing fuel tank. The palletised equipment will be installed during a planned period of heavy maintenance by the company, an airline or a third-party support organisation.

For the 757, the installation is in the belly fairing, and comprises two air separation modules, a heat exchanger and a network of pipes running to the centre wing tank.

Marshall is meanwhile expanding its production of auxiliary fuel tanks, and will install its first examples on an A318 Elite at its Cambridge airport site from next month. The work builds on previous orders to produce auxiliary fuel tanks for the Boeing 747, 777-200LR and the US Navy's 737-based P-8 Poseidon maritime patrol aircraft.

The company has delivered the first three shipsets of six under-floor tanks each for the P-8, and will increase output to 66 tanks in 2011 and around 150 a year at full rate, says Steve Thomas, head of operations for Marshall Aerospace Aerostructures.

L'inertage va devenir obligatoire en 2017 avec une étape intermédiaire en 2014 (moitié de la flotte équipée).
La solution de marshall pour les 767 et 757 utilise l'azote présent dans l'air
Installation dans les carénages à l'emplanture des ailes
A noter, marshall fourni également des kit pour les réservoirs de soute des boeing

Bonne journée

Bonjour tous

Quelques compléments sur l'inertage des réservoirs

http://en.wikipedia.org/wiki/Inerting_system#Current_FAA_Rules_on_Inerting_in_Aircraft

Current FAA Rules on Inerting in Aircraft
After what it said was seven years of investigation, the FAA proposed a rule in November 2005, in response to an NTSB recommendation, which would require airlines to "reduce the flammability levels of fuel tank vapors on the ground and in the air". This was a shift from the previous 40 years of policy in which the FAA focused only on reducing possible sources of ignition of fuel tank vapors.

The FAA issued the final rule on July 21, 2008. The rule amends regulations applicable to the design of new airplanes (14CFR§25.981), and introduces new regulations for continued safety (14CFR§26.31-39), Operating Requirements for Domestic Operations (14CFR§121.117) and Operating Requirements for Foreign Air Carriers (14CFR§129.117). The regulations apply to airplanes certificated after January 1, 1958 of passenger capacity of 30 or more or payload capacity of greater than 7500 pounds. The regulations are performance based and do not require the implementation of a particular method.

. The proposed rule would affect all future fixed-wing aircraft designs (passenger capacity greater than 30) , and require a retrofit of more than 3,200 Airbus and Boeing aircraft with center wing fuel tanks, over nine years. The FAA had initially planned to also order installation on cargo aircraft, but this was removed from the order by the Bush administration. Additionally, regional jets and smaller commuter planes would not be subject to the rule, because the FAA does not consider them at high risk for a fuel-tank explosion.[2] The FAA estimated the cost of the program at US$808 million over the next 49 years, including US$313 million to retrofit the existing fleet. It compared this cost to an estimated US$1.2 billion "cost to society" from a large airliner exploding in mid-air. The proposed rule comes at a time when nearly half of the U.S. airlines' capacity is on carriers that are in bankruptcy.[2]

The order affects aircraft whose air conditioning units have a possibility of heating up the center wing fuel tank. Some Airbus A320 and Boeing 747 aircraft are slated for "early action". Regarding new aircraft designs, the Airbus A380 does not have a center wing fuel tank and is therefore exempt, and the Boeing 787 has a fuel tank safety system that already complies with the proposed rule.[3] The FAA has stated that there have been four fuel tank explosions in the previous 16 years -- two on the ground, and two in the air -- and that based on this statistic and on the FAA's estimate that one such explosion would happen every 60 million hours of flight time, about 9 such explosions will probably occur in the next 50 years. The inerting systems will probably prevent 8 of those 9 probable explosions, the FAA said. Before the inerting system rule was proposed, Boeing stated that it would install its own inerting system on airliners it manufactures beginning in 2005. Airbus had argued that its planes' electrical wiring made the inerting system an unnecessary expense.[2]

As of December 2, 2009, the FAA has a pending rule to increase the standards of on board interting systems again. New technologies are being developed by others to provide fuel tank inerting:

(1) The OBIGGS system, tested in 2004 by the FAA and NASA, with an opinion written by the FAA in 2005 [7]. This system is currently in use by many military aircraft types, including the C-17. This system provides the level of safety that the proposed increase in standards by the proposed FAA rules has been written around. Critics of this system cite the high maintenance cost reported by the military.

(2) Three independent research and development firms have proposed new technologies in response to Research & Development grants by the FAA and SBA. The focus of these grants is to develop a system that is superior to OBIGGS that can replace classic inerting methods. None of these approaches has been validated in the general scientific community, nor have these efforts produced commercially available products. All the firms have issued press releases or given non-peer reviewed talks.

Donc à priori :
Sous 30 PAX et 7500 lb de CU pas d'inertage
CARGO : pas d'inertage (???)
Semble effectivement concerner que les réservoirs de caisson central, ce qui explique que l'A380 en soit dispensé... la version -800 n'a que des réservoirs d'aile (y a de la place dans les ailes de cette machines...).

Un exemple d'OBIGGS (c'est le terme pour le dispositif...)

http://www.dta.airliquide.com/fr/notre-offre/aeronautics/programmes-aeronautiques/avions-de-transport-militaires/obiggs-pour-c27j.html

A suivre

Bonjour !

Tu as raison, Poncho !
Mais ça ne me plait pas .... pour autant !
Pas de systèmes électriques dans les réservoirs d'aile ou de Queue ??
Pompes, jauges, etc !
Plus les risques de foudre !
Et comment ils réchauffent leurs quasi 300 000 litres de kéro, les A380, ! Rien d'électrique ??

Une 1/2 mesure de la FAA !!


A vérifier / Si Boeing a inerté tous les réservoirs du 787 ?
A priori si on génère de l'air sans oxygène, ce n'est plus qu'une question de débit et de tuyaux !

--------------- Trouvé celà, Extrait Aviation today 2006 --------------

http://www.aviationtoday.com/am/categories/bga/Regulatory-Report_284.html

In other words, no amount of maintenance is likely to eliminate the hazard of ignition sources in fuel tanks. In fact, the Sandia report demolishes the FAA's comforting blandishments. The report talks about any number of ADs still to be issued, so the hunt for ignition sources extends into perpetuity. One wonders why this independent evaluation was not published earlier, as it likely would have led to a more modest reckoning of the effects of the SFAR 88-related ADs.

The Sandia effort probably should be taken to the next step: an independent evaluation of the FAA's inerting scheme, which relaxes the allowable oxygen content of the fuel/air vapors in the tank from 9 percent to 12 percent, foregoes inerting on descent, and envisions providing a flow of nitrogen enriched air only to heated center wing tanks. Moreover, a 10-day MEL is envisioned, so the airplane can operate without inerting for up to this long, with the various "unexpected" hazards documented in the Sandia report.

One suspects that an independent evaluation of the inerting scheme would leave the FAA's fuel tank safety program dead in the water. Inerting of all tanks, all the time, would provide protection against a combination of faults, even with Mother Nature thrown in as the stirrer with lightning, but that would require more than the minimalist approach now being entertained.

It should be pointed out that the National Transportation Safety Board (NTSB) has called for the elimination in all tanks of the hazard posed by flammable vapors. In other words, the NTSB never put its faith in the SFAR 88 ADs to reduce hot spots, preferring instead to eliminate the explosive fumes.

Indeed, an NTSB letter dated March 23 and obviously submitted after the Sandia report, suggested the FAA needs to do better:

"The fact remains that wing tanks have exploded ... the Board ... believes that the FAA should at least provide design guidance to encourage the use of available nitrogen generation technologies for all fuel tanks ... Further, the Safety Board does not believe that cargo airplanes should be omitted ...

"Finally, the Safety Board notes that additional benefits from onboard flammability reduction systems can be realized, but that the FAA does not address any of these. Nitrogen-producing equipment can be used to provide fire protection for avionics, electrical compartments, unoccupied spaces, and cargo compartments. For example, on February 8, 2006, a DC-8 cargo airplane was on fire when it landed at Philadelphia, Pennsylvania, International Airport. The fire was quickly spreading to the cargo area, and the crew may have had only a few extra minutes in which to land the airplane. An inerting system may have suppressed or extinguished the fire, significantly improving the safety of the flight."

To be sure, the aviation industry is in no economic shape to undertake the cost of retrofitting proper inerting. In this regard, the Sandia report on the SFAR 88 ADs might help to convince Congress of the absolute necessity of authorizing the funds necessary for inerting.

Formation of new safety analysis effort

On March 21 the Federal Aviation Administration announced the formation of an airplane-level safety analysis group under the auspices of the Aviation Rulemaking Advisory Committee (ARAC). The new ARAC is designed to pull together the potentially malignant "interaction of systems." The group has been specifically tasked to examine specific risk, latent risk, and the extent to which, under the minimum equipment list (MEL), an airplane can be exposed to a critical failure.

According to the FAA's tasking document, "The report will document the approach used to establish whether a significant latent failure should be allowed to leave the airplane one failure away from a catastrophic condition." The maintenance implications relate to the MEL, and whether or not a component must be fixed to insure that the airplane is not one failure away from catastrophe. Although not specifically mentioned, the task ought to relate to the fuel system safety issue cited above. (See www.faa.gov/regulations_policies/rulemaking/recently_published/media/TAE_notice.pdf)

A dangerous foible

"The actions specified in this AD are intended to detect and correct improper rigging of the propeller feathering linkage. The above issue, if uncorrected, could result in degraded performance and poor handling qualities with consequent loss of control of the airplane," the FAA intones in an AD published March 23 (see http://thefederalregister.com/d.p/2006-03-22-E6-4123). A spate of recent MU-2 accidents prompted the FAA to conduct a safety evaluation of the MU-2B, and this AD is one of the outcomes. The MU-2 is a twin-turboprop with jetlike performance; one wonders how many accidents were attributable to this foible.

JPRS

Bonjour

Remise à plat intéressante ! Piqure de rappel !
La FAA et ses 1/2 mesures, cernant surtout le cas du 747 ..;
Et en laissant pas mal en route !
Et Airbus qui y en à profité pour passer à travers les mailles, pour le A380 !

Pas satisfaisant pour ma fibre sécuritaire tout ça !

La finance avant la sécurité ... au minimum légal, c'est mon avis !

JPRS

La sécurisation des réservoirs, ça traîne lamentablement !

Les constructeurs, comme les utilisateurs y vont à reculons aux USA , ça n'avance pas !
Malgré les efforts de la FAA ...
Et l'EASA qui regarde ce qui se passe ... beuh
Jusqu'au prochain accident ?? Improbable ... hum !

Du Seattle Times, un excellent article de Dominic Gates !

http://seattletimes.nwsource.com/html/businesstechnology/2018436447_boeing15.html

A rapprocher de cet AD US ??, pas vu mentionné l'EASA !

Un AD qui va certainement être suivi par Airbus ... Pour des A300 et A310 !
Une révision des cablages dans une baie electro .
Toujours pour les mêmes raisons, des défauts d'isolation pouvant induire des surtensions dans les réservoirs !
Comme quoi, les régulations tombent sur tous et pour le même motif ...
A rapprocher de Boeing, qui traîne les pieds pour modifier ses 757 !

Drôle de question ... un avion est il trop vieux pour mériter une mise à jour de sécurité ... hum !
Ou ... un freighter peut il prendre plus de risques ... (Cas des B757)

http://www.gpo.gov/fdsys/search/pagedetails.action?granuleId=2012-14048&packageId=FR-2012-06-18&acCode=FR

Déterrage de fil..

Inertage du réservoir central,  judicieux ou pas ? Il faut relativiser et comparer avec l'absence totale de dispositif d'extinction incendie sur le pont principal des avions cargos, rétrofités et neufs juste sortis de la chaîne. On vole pendant des heures avec des dizaines de tonnes de frêt et la seule procédure en cas de feu/fumée est de dépressuriser l'avion et de voler à 25.000 ft et de se dérouter.

Beochien a écrit:Bonjour !

Tu as raison, Poncho !
Mais ça ne me plait pas ....  pour autant !
Pas de systèmes électriques dans les réservoirs d'aile ou de Queue ??
Pompes, jauges, etc !
Plus les risques de foudre !
Et comment ils réchauffent leurs  quasi 300 000 litres de kéro, les A380, ! Rien d'électrique ??

Une 1/2 mesure de la FAA !!


A vérifier / Si Boeing a inerté tous les réservoirs du 787 ?
A priori si on génère de l'air sans oxygène, ce n'est plus qu'une question de débit et de tuyaux !
.../...

JPRS

Le problème du réservoir central c'est qu'il situé au dessus des groupes de conditionnement d'air (packs) qui génèrent des températures très chaudes dans cette zone, ce qui chauffe les vapeurs du réservoir au fur et à mesure qu'il se vide (c'est ce réservoir qui est utilisé en premier)

Pour l'A380, les 2 packs sont localisés en avant de la position habituelle des réservoirs centraux or il ne possède pas de réservoir central.

Le carburant n'est pas réchauffé électriquement sur tous les Boeing que je connais, c'est par de l'air chaud ou par échangeur huile/carbu et ce réchauffage ne se fait pas au niveau du réservoir (aile ou central) mais sur le moteur lui même. BA 38...

Le 787 possède un inertage de série pour tous les réservoirs donc y compris les ailes, à la différence du 777 (depuis les sortie usine d'il y a 5 ans environ) qui n'inerte que le réservoir central comme sur 737. Le système est simple (air prélevé sur les réacteurs puis séparation dans systèmes à membrane) et injection dans réservoir.

Les réservoirs d'aile sont structurellement toujours plus froids que les réservoirs centraux ce qui rend leur carburant plus éloigné de la zone de risque d'inflammation. Ceci pour le kérosène JET A et encore plus pour le kérosène militaire JP4.


L'article que tu cites parle du cout d'exploitation de l'OBBIGS du C17, c'est probablement parce que le système est plus compliqué que pour les avions de ligne; le C17 possède 12 bouteilles de nitrogen:

- on prélève de l' air sur un étage élévé du compresseur du réacteur . L'air peut aussi provenir d'un prélèvement APU.
- cet air est refroidi puis dirigé vers un Air Separation Module fonctionnant électriquement.
- l' ASM est contitué de 3 zéolites qui séparent l'oxygène et l' azote de l' air ; quand des 3 est saturé , un des 3 autres prend le relais, celui qui est saturé en oxygène évacue cet oxygène vers l' extérieur de l' avion ainsi que l' humidité résiduelle .
- L' air enrichi en azote ( NEA = nitrogen enriched air ) est comprimé par un compresseur hydraulique
- le NEA est comprimé à 3000 PSI et refroidi après sa compression et est stocké dans des bouteilles .
- Le NEA est envoyé dans les réservoirs au fure et à mesure de la consommation ( abaissement du niveau de carburant dans les ailes , donc augmentation du volume gazeux = ullage en anglais )
- La difficulté du processus est de gérer les variations de pression dans les réservoirs en fonction des variations d e pression extérieure ( altitude ) en respectant les limites de pression différentielle qui conditionnent la résistance structurale des réservoirs . Par exemple lors des decentes dites tactiques à 9000 ft/mn . ( extrait manuel )

C17:





Historiquement, le B 47 a eu un inertage par carboglace... et le Victor avait un système d'inertage pour la perche de ravitaillement qui traversait le fuselage:

Victor: