EASA Rapports et Airworthiness Directives

PARIS, 23 septembre (Reuters) - Les autorités européennes ont ordonné des vérifications sur des capteurs de vitesse fabriqués par l'américain Goodrich (GR.N: [Vous devez être inscrit et connecté pour voir ce lien]) équipant des Airbus A330, plusieurs semaines après avoir restreint l'utilisation de capteurs fournis par le français Thales (TCFP.PA: [Vous devez être inscrit et connecté pour voir ce lien]).
Le fonctionnement défectueux de capteurs de vitesse Thales a peut-être joué un rôle dans l'accident du vol AF447 d'Air France (AIRF.PA: [Vous devez être inscrit et connecté pour voir ce lien]) qui s'est abîmé dans l'Atlantique le 1er juin entre Rio et Paris, entraînant la mort des 228 personnes à bord.
Dans une directive datée du 22 septembre, l'Agence européenne de la sécurité aérienne indique que des dysfonctionnements ont été rapportés concernant certains capteurs Goodrich, aussi appelés sondes Pitot. S'ils ne sont pas corrigés, ils pourraient provoquer des fuites d'air et perturber les mesures de vitesse

The European Aviation Safety Agency (EASA) has mandated that operators of [Vous devez être inscrit et connecté pour voir ce lien] family aircraft and [Vous devez être inscrit et connecté pour voir ce lien]/300 models perform repetitive inspections of the composite skins on the aircraft's left and right-side elevator assemblies from 15 December.
An earlier directive, issued by French regulators in 2004 after maintainers found debonding on the right-hand elevator of an [Vous devez être inscrit et connecté pour voir ce lien] during a scheduled maintenance task, called for a one-time inspection to search for flaws in the sandwich structure of the skin panels of the aircraft models.
Along with the initial inspections defined in the previous directive, the new mandate calls for repeat inspections for evidence of debonding every six years.
"Investigation has revealed that this debonding may have been caused by water ingress and, if not detected and corrected, might compromise the structural integrity of the elevators," says EASA.

European safety regulators are extending fuel-icing prevention modifications to [Vous devez être inscrit et connecté pour voir ce lien] and [Vous devez être inscrit et connecté pour voir ce lien] aircraft powered by Rolls-Royce Trent engines.
The European Aviation Safety Agency (EASA) has issued an airworthiness directive ordering replacement of fuel-oil heat exchangers in [Vous devez être inscrit et connecté pour voir ce lien] and 700 powerplants.
[Vous devez être inscrit et connecté pour voir ce lien] engines for the [Vous devez être inscrit et connecté pour voir ce lien] are already the subject of a similar directive, the result of investigations into the [Vous devez être inscrit et connecté pour voir ce lien] 777 accident at London Heathrow last year.
But an incident at Manchester in May, involving an Etihad A330, led [Vous devez être inscrit et connecté pour voir ce lien] to suggest that Trent engines on the A330 and [Vous devez être inscrit et connecté pour voir ce lien]/600 might also need precautionary modification.
EASA's new directive states: "The incident has indicated the potential susceptibility to ice blockage for Airbus aircraft in combination with [Rolls-Royce] engines that feature similar fuel systems to the Trent 800."
It is requiring heat exchangers in Trent 500s and 700s to be modified within 6,000 flight hours from 10 July 2009, or before 1 January 2011, whichever falls first.

The European Aviation Safety Agency (EASA) has mandated that operators of a large variety of [Vous devez être inscrit et connecté pour voir ce lien] aircraft fitted with Hamilton Sundstrand ram air turbines (RATs) perform inspections and part replacement on the backup devices.
The action comes after Hamilton Sundstrand, a subsidiary of United Technologies, reported a failure during a wind tunnel test of a balance weight fastening screw on a RAT turbine cover, according to an [Vous devez être inscrit et connecté pour voir ce lien] issued today.
"After investigation, it has been discovered that a batch of screws, which are used to attach the balance washers of the Hamilton Sundstrand RAT turbine assembly, have not been subject to the correct heat treatment and are consequently exposed to potential fracture," EASA states.
If the screws fracture and release the balance weights, EASA says the RAT vibrations can increase and possibly cause "detachment of RAT parts and consequent loss of RAT functionality".
In the worst case, the problem could leave pilots with no control over an aircraft if all engines were to flame out, says EASA. Airbus uses RATs to power the aircraft's essential systems in the absence of engine power.
The directive, which becomes effective on 24 December, applies to the [Vous devez être inscrit et connecté pour voir ce lien]-600, A310, [Vous devez être inscrit et connecté pour voir ce lien], [Vous devez être inscrit et connecté pour voir ce lien] and [Vous devez être inscrit et connecté pour voir ce lien] families of aircraft.
Operators must identify the suspect RAT turbine assemblies and replace defective parts at the next RAT spin test or within a specified number of flight hours or months, whichever comes first

A ram air turbine (RAT) is a small [Vous devez être inscrit et connecté pour voir ce lien] that is connected to a hydraulic pump, or [Vous devez être inscrit et connecté pour voir ce lien] used as a power source for [Vous devez être inscrit et connecté pour voir ce lien]. The RAT generates power from the airstream due to the speed of the aircraft.
With the exception of crop dusters (see below), modern aircraft only use RATs in emergency - in case of the loss of both primary and auxiliary power sources the RAT will power vital systems (flight controls, linked hydraulics and also flight-critical instrumentation). Some RATs produce only hydraulic power, which is in turn used to power electrical generators. In some early aircraft, these were permanently mounted and operated a small electrical generator or [Vous devez être inscrit et connecté pour voir ce lien].
Modern aircraft generate power through the main engines or an additional fuel-burning turbine called an [Vous devez être inscrit et connecté pour voir ce lien], which is often a small tail-mounted turbine engine. The RAT generates power from the airstream due to the speed of the aircraft, and if aircraft speeds are low the RAT will produce less power. In normal conditions the RAT is retracted into the fuselage (or wing), deploying automatically upon emergency power loss. In the time between power loss and RAT deployment, batteries are used.
RATs are common on military aircraft, where sudden and complete loss of power is more likely. Fewer civilian aircraft are fitted with them, although most commercial airliners are (since the 1960s on the Vickers [Vous devez être inscrit et connecté pour voir ce lien]). The [Vous devez être inscrit et connecté pour voir ce lien] has the largest RAT propeller in the world at 1.63 m in diameter, but around 80 cm is more common. A typical large RAT on a commercial aircraft can be capable of producing, depending on the generator, from 5 to 70 kW. Propellers started as two-bladed or four-bladed models but military (and increasingly commercial) models now use ducted multi-blade fans. Smaller, low airspeed models may generate as little as 400 watts.
In other military uses, pod-fitted systems such as the [Vous devez être inscrit et connecté pour voir ce lien] or electronic systems (e.g. the [Vous devez être inscrit et connecté pour voir ce lien] TJS) can be powered by a RAT in standard operation. Also, some free-fall nuclear weapons, such as the British [Vous devez être inscrit et connecté pour voir ce lien] and [Vous devez être inscrit et connecté pour voir ce lien] used RATs to power [Vous devez être inscrit et connecté pour voir ce lien] and firing circuits.
In non-military use, RATs have been used to power [Vous devez être inscrit et connecté pour voir ce lien] to pressurize the spray systems on aircraft that are used as [Vous devez être inscrit et connecté pour voir ce lien] to deliver liquid agents to cropland. The major reason for choosing a RAT is safety; using a RAT allows the FAA-certified engine and power systems on the aircraft to remain unmodified. There is no need to use an engine power takeoff to drive the pump, and the pump can be placed low or below the exterior of the airframe greatly simplifying plumbing, and being the lowest point in the plumbing, it will have gravity feed from the spray tanks and never need to be primed. In the event of a pump failure that could result in seizure, there is no effect on the flying ability of the aircraft or its systems apart from the obvious fact that the spray systems are non functional.
[Vous devez être inscrit et connecté pour voir ce lien] and [Vous devez être inscrit et connecté pour voir ce lien] are the main US suppliers of RAT systems.

By April 30, Airbus A330 and A340 operators will be required to make a detailed visual inspection of aircraft equipped with a Thales Avionics AoA (angle of attack) probe with part no. C16291AA.
The inspections are necessary to identify and replace parts suspected of causing inaccurate AoA indications. The requirement comes from a Feb. 9 airworthiness directive issued by the European Aviation Safety Agency (EASA) after final assembly line testing revealed that AoA data from two different aircraft were incorrect. Flight data analysis confirmed the inaccuracies.
Thales, in its examination of the suspect probes, discovered oil residue between the stator and rotor parts of the AoA vane position resolvers. The residue, according to EASA, was the result of improperly cleaned machine oil used in manufacturing the resolvers.
The oil residue becomes viscous at low temperatures, especially at cruise altitudes, and can cause a lag in AoA vane movement. This, in turn, can lead to erroneous measurement of the aircraft’s angle of attack. Should two or three probes become simultaneously affected and provide incorrect indications, the aircraft’s AoA protection would be late to activate, which, when combined with flight at a high angle of attack, creates an unsafe condition.

FAA calls for Boeing 737 thrust reverser inspections

The US FAA wants operators of more than 1,000 next generation [Vous devez être inscrit et connecté pour voir ce lien] 737s to begin periodic inspections of the twinjet's thrust reverser assemblies.
The proposed airworthiness directive (AD), to be issued on 22 March, was prompted by reports of damage to the attachment fittings for thrust reverser actuators of in-service aircraft. Damage is caused when bushings in the actuator attach fitting wear out due to friction during the normal course of operations.
"We are proposing this AD to detect and correct such damage, which could result in actuator attach fitting failure, loss of the thrust reverser auto re-stow function, and consequent loss of control of the airplane," says the agency. "Loss of the thrust reverser auto re-stow function removes one of the three primary levels of protection against an uncommanded thrust reverser deployment."
While certain aircraft must get a one-time inspection of hydraulic actuator ends within 7,500h of the finalised AD, all aircraft must have repetitive detailed inspections of thrust reverser mechanisms every 7,500 flight hours under the proposal.
The FAA estimates the AD will apply to 1,070 US-registered 737-600/700/700C/800/900 and 900ER-series aircraft, collectively costing an estimated $2 million for the one-time inspections and $2 million for each 7,500 flight hour inspection.

• que, dans la partie "causant" l'AD (le motivant sur les plans technique, sécuritaire et juridique), il est tout a fait normal de présenter le "worst case" (dans le raisonnement),
  
• même si les cas concrets détectés, et susceptibles de progresser jusqu'au déclenchement de la séquence des événements capable de conduire jusqu'au 'cas le pire', si aucune mesure conservatoire, ou de solution fondamentale n'est mise en place.
  

Leur approche, leurs avis infondés, non étayés et non étayables, .... n'ont aucune pertinence, et n'intéressent pas grand-monde !

L'UE propose d'inspecter 170 avions Airbus

Les autorités européennes de régulation de l'aviation ont demandé mercredi l'inspection minutieuse de plus de 170 avions monocouloirs Airbus en service dans le monde en raison d'une série d'écrous douteux, et le remplacement des éventuelles pièces défecteuses.
Cette mesure de sécurité concerne certains des biréacteurs A319, A320 et A321 de l'avionneur européen.
Selon l'Agence européenne de la sécurité aérienne, "un grand nombre" d'écrous suspects ont été installés dans le fuselage et dans la zone du réservoir de carburant des avions pendant l'assemblage. Si l'on n'y remédie pas, l'utilisation de ces pièces pourrait avoir des conséquences à long terme et altérer "l'intégrité structurelle" des appareils concernés, avertit l'agence.
Les autorités de régulation de l'Union européenne ont cependant indiqué que des tests évaluant la fatigue des métaux, la corrosion et d'autres problèmes avaient montré que les pièces douteuses ne faisaient pas courir de danger immédiat.
L'Agence européenne de la sécurité aérienne a donc proposé d'ordonner que les inspections détaillées et l'éventuel remplacement des écrous soient réalisés dans un délai de six à 12 ans après le premier vol des avions concernés.
Un porte-parole d'Airbus a déclaré que le groupe et les régulateurs avaient précédemment déterminés qu'une intervention immédiate n'était pas nécessaire, car les problèmes potentiels n'apparaîtraient pas avant longtemps, voire jamais.

EASA Calls For A320 Fixes

The European Aviation Safety Agency is calling on operators of Airbus A320 family aircraft to address issues related to problems with the cargo loading system and cracking fuselage nuts.
A May 5 airworthiness directive (AD) addresses a previously identified problem with tie down points of YZ latches on the cargo loading system of A319s, A320s and A321s, which do not withstand maximum loading requirements leading to potential damage in the forward and aft lower deck cargo holds. EASA says the rectifying action, called for in 2006, has not been properly installed across the fleet.
The safety agency warns that it recently realized that on some aircraft the fix “has been applied only on one of the lower deck cargo holds (fwd or aft) while both cargo compartments were concerned by the modification.”
The second AD, issued May 4, warns that parts inspection during production showed some nuts used on the fuselage of A318, A319, A320, and A321s showed cracks. “A large number of these nuts are fitted on primary structural elements, which could have long-term consequences,” EASA says, while noting that no immediate action to address the issue is necessary.
EASA is therefore calling “a detailed inspection of the affected nuts, associated correction actions, depending on findings, and replacement of the affected [part number] nuts with new ones having the same [part number].”
Operators are supposed to inspect the affected parts for aircraft flying six years or more and, within 90 days, report those findings to Airbus.

Airbus A380 Engine Pylons May Need Air Holes to Avoid Fire Risk

Airlines operating Airbus SAS’s A380 superjumbo may be required to modify equipment that connects the plane’s engines to its wings, safety regulators said, citing a risk of overheating that could cause a fire.

Test flights revealed a buildup of heat in the pylons of A380s equipped with Rolls-Royce Holdings Plc Trent 900 engines, the European Aviation Safety Agency said today in a proposed airworthiness directive which would require carriers to install ventilation holes in some of the panels covering the structures.

“This condition could, in case of a heavy fuel leak, lead to an ignition of fuel vapors, possibly resulting in a fuel fire and consequent damage to the aeroplane and/or injury to its occupants,” EASA said in the directive, which is open for consultation until Oct. 28. If made mandatory, the modifications would have to be implemented within a 10-month period, it said.

Australian carrier [Vous devez être inscrit et connecté pour voir ce lien] grounded its A380s for 23 days last year after a Trent 900 failure prompted an emergency landing in [Vous devez être inscrit et connecté pour voir ce lien] on Nov. 4. Rolls-Royce has since carried out modifications to address issues with a faulty oil pipe, and the glitch disclosed today is unrelated, Airbus said.

The planned directive would affect the Trent-equipped -841 and -842 variants of the A380, all manufacturer serial numbers, except for planes that have already been modified, EASA said.

Today’s proposal follows a bulletin issued by Airbus to A380 operators on July 25 after the manufacturer uncovered the overheating issue during its own test flights, spokesman [Vous devez être inscrit et connecté pour voir ce lien] said by phone, adding that the EASA directive is a standard response. Schaffrath said that the period permitted to address the problem indicates the low perceived risk.

EASA said no-one was immediately available to comment further, and London-based Rolls-Royce declined to comment.

A380s equipped with Engine Alliance turbines made by [Vous devez être inscrit et connecté pour voir ce lien] and Pratt and Whitney aren’t affected.

Airlines operating Airbus SAS’s A380 superjumbo may be required to modify equipment that connects the plane’s engines to its wings. Photographer: Jason Alden/Bloomberg.

Airlines operating Airbus SAS’s A380 superjumbo may be required to modify equipment that connects the plane’s engines to its wings, safety regulators said, citing a risk of overheating that could cause a fire.

Pylône ? Serait-ce un 'problème-moteur' , ... ou un problème de l'airframe ? Quelle est la vraie "root cause" ?

Test flights revealed a buildup of heat in the pylons of A380s equipped with Rolls-Royce Holdings Plc Trent 900 engines, the European Aviation Safety Agency said today in a proposed airworthiness directive which would require carriers to install ventilation holes in some of the panels covering the structures.

“This condition could, in case of a heavy fuel leak, lead to an ignition of fuel vapors, possibly resulting in a fuel fire and consequent damage to the aeroplane and/or injury to its occupants,” EASA said in the directive, which is open for consultation until Oct. 28. If made mandatory, the modifications would have to be implemented within a 10-month period, it said.

Australian carrier [Vous devez être inscrit et connecté pour voir ce lien] grounded its A380s for 23 days last year after a Trent 900 failure prompted an emergency landing in [Vous devez être inscrit et connecté pour voir ce lien] on Nov. 4. Rolls-Royce has since carried out modifications to address issues with a faulty oil pipe, and the glitch disclosed today is unrelated, Airbus said.

The planned directive would affect the Trent-equipped -841 and -842 variants of the A380, all manufacturer serial numbers, except for planes that have already been modified, EASA said.

Today’s proposal follows a bulletin issued by Airbus to A380 operators on July 25 after the manufacturer uncovered the overheating issue during its own test flights, spokesman [Vous devez être inscrit et connecté pour voir ce lien] said by phone, adding that the EASA directive is a standard response. Schaffrath said that the period permitted to address the problem indicates the low perceived risk.

EASA said no-one was immediately available to comment further, and London-based Rolls-Royce declined to comment.

A380s equipped with Engine Alliance turbines made by [Vous devez être inscrit et connecté pour voir ce lien] and Pratt and Whitney aren’t affected.