Home » ASN News
EASA publishes Emergency AD following control issues on A321 with blocked angle of attack probes
10 December 2014

EASA publishes Emergency AD following control issues on A321 with blocked angle of attack probes

File photo of AOA probes on an Airbus A330 (photo: ATSB)

File photo of AOA probes on an Airbus A330 (photo: ATSB)

The European Aviation Safety Agency (EASA) issued an Emergency Airworthiness Directive for several Airbus models, detailing emergency procedures in the case of undue activation of Alpha Protection.

An occurrence was reported where an Airbus A321 encountered a blockage of two Angle Of Attack (AOA) probes during climb, leading to activation of the Alpha Protection (Alpha Prot) while the Mach number increased. The flight crew managed to regain full control and the flight landed uneventfully.
When Alpha Prot is activated due to blocked AOA probes, the flight control laws order a continuous nose down pitch rate that, in a worst case scenario, cannot be stopped with backward sidestick inputs, even in the full backward position. If the Mach number increases during a nose down order, the AOA value of the Alpha Prot will continue to decrease. As a result, the flight control laws will continue to order a nose down pitch rate, even if the speed is above minimum selectable speed, known as VLS.

This condition, if not corrected, could result in loss of control of the aircraft.
This systems is installed on Airbus A318, A319, A320, A321, A330 and A340 aircraft. To address this unsafe condition, Airbus have developed a specific Aircraft Flight Manual (AFM) procedures. The Airworthiness Directive requires amendment of the applicable AFM.

This is considered to be an interim action and further AD action may follow.

More information:

 

Brazil issues emergency AD for inspection of horizontal stabilizer attachment nuts

Embraer Phenom 100 file photo (photo: JBabinski380 / CC:by)

Embraer Phenom 100 file photo (photo: JBabinski380 / CC:by)

The Brazilian regulator Agência Nacional de Aviação Civil (ANAC) issued an Emergency Airworthiness Directive (EAD) to inspect barrel nuts in the horizontal stabilizer-to-vertical stabilizer attachment joint on Embraer EMB-500 Phenom jets.

During an inspection on the assembly line, cracking in the barrel nuts at the horizontal stabilizer-to-vertical stabilizer attachment joint was found on an Embraer Phenom jet.

This prompted ANAC to issue an EAD to detect and correct cracking of the barrel nuts at the horizontal stabilizer-to-vertical stabilizer attachment joint, which could result in reduced structural integrity of the affected part and consequent detachment of the horizontal stabilizer from the airplane.

The inspection must be accomplished within three flight cycles of July 25, 2014.

More information:

 

 

Brazil issues emergency AD to prevent engine separations on Embraer ERJ-190 jets

Right hand engine pylon on an Embraer ERJ-190 (photo: H.Ranter/ASN)

Right hand engine pylon on an Embraer ERJ-190 (photo: H.Ranter/ASN)

The Brazilian regulator Agência Nacional de Aviação Civil (ANAC) issued an Emergency Airworthiness Directive (EAD) to prevent engine separations on Embraer ERJ-190 jets.

During maintenance on an Embraer ERJ-190 passenger jet of Virgin Australia on 25-26 June it was discovered that there was an issue with an engine pylon lower link fitting assembly. Virgin Australia subsequently checked the entire fleet of 17 ERJ-190’s and found similar issues with nine of them.

The manufacturer, Embraer, then issued Alert Service Bulletins on June 27, which were followed by ANAC’s Emergency Airworthiness Directive that mandated the actions described in these service bulletins.
The actions required are intended to prevent the shear pins installed on the left hand and on the right pylon outboard and inboard fittings to get loose, which could lead to failure of one of these fittings and consequent separation of the engine from the wing.

Operators are to re-torque the inboard and outboard lower link fitting assembly on the  left hand and on the right hand engine pylon. The EAD is considered an interim action. These action are required to be repeated at intervals not to exceed 600 flight cycles or 750 flight hours, whichever occurs first.

More information:

 

Emergency AD issued to prevent in-flight deployment of Challenger 600 thrust reversers

File photo of a Challenger 600 with thrust reverser deployed (Photo: User:Omoo / CC:by)

File photo of a Challenger 600 with thrust reverser deployed (Photo: User:Omoo / CC:by)

Transport Canada issued an emergency Airworthiness Directive (AD), requiring checks of thrust reversers on the Bombardier CL-600-1A11 Challenger 600 corporate jet.

According to Transport Canada there have been two reported incidents of partial deployment of an engine thrust reverser on a Challenger 600 jet in-flight.
This was caused by a failure of the translating sleeve at the thrust reverser actuator attachment points. Inspection of the same area on some other thrust reversers revealed cracks emanating from the holes under the nut plates.
In both incidents, the affected aircraft landed safely without any noticeable controllability issues. Transport Canada decided to issue an emergency AD to prevent further incidents or accidents.

Bombardier Inc. has revised the Aircraft Flight Manual (AFM) to prohibit the thrust reverser operation on affected airplanes. Additionally, as an interim corrective action, Bombardier has issued
an alert service bulletin requiring an inspection and/or a mechanical lock out of the thrust reverser to prevent it from moving out of forward thrust mode.
The AD mandates the incorporation of revised AFM procedures and compliance with the service bulletin for all affected CL-600-1A11 aircraft.

More information:

 

Transport Canada issues emergency AD addressing Challenger 604 potential APU fuel leak

File photo of a Challenger 604 (H.Ranter/ASN)

File photo of a Challenger 604 (H.Ranter/ASN)

Transport Canada issued an emergency Airworthiness Directive (AD), limitating landing/taxi light operations on ground due to potential fuel  leakage relating to specific models of the Bombardier CL-600-2B16 Challenger 604 corporate jet.

Bombardier Inc. has determined that there is a potential for fuel leakage from the auxiliary power unit (APU) boost pump component installations in the right hand landing lights compartment. On a hot day, the temperatures in the landing light compartment as result of the heat generated by the taxi lights and/or the landing lights on the ground, can reach the auto-ignition temperature of the fuel and may ignite any fuel/fumes present in the right hand landing light compartment.
In order to mitigate the potential safety hazard, Bombardier Inc. has revised the Aircraft Flight Manual (AFM) to introduce additional limitations for operation of the landing/taxi lights on the ground.
This AD is being issued to mandate compliance with the revised AFM limits for landing/taxi light operations for the affected aeroplanes.

 

More information:

 

FAA issues Emergency AD to prevent TFE731 engine turbine blade separations

Honeywell TFE731 engine

Honeywell TFE731 engine

The FAA issued an Emergency airworthiness directive (AD), detailing inspections of specific Honeywell TFE731 turbofan engines following reports of 2nd stage low-pressure turbine (LPT2) blade separations.

On June 10, 2014 the U.S. Federal Aviation Administration issued an Emergency airworthiness directive (AD), prompted by reports of 2nd stage low-pressure turbine (LPT2) blade  separations on TFE731 engines. Analysis indicates the presence of casting anomalies at or near the root of the LPT2 blade. This condition, if not corrected, could result in LPT2 blade failure, multiple engine in-flight shutdowns, and damage to the airplane.

The AD requires before further flight a review of the engine log book maintenance records to determine if any affected engines are installed. Operation is prohibited of an airplane with two or more affected engines that have LPT2 blades with less than 250 operating hours since new after receipt of the emergency AD.

Affected engine series are: Honeywell International Inc. (Type Certificate previously held by AlliedSignal Inc., Garrett Turbine Engine Company) TFE731-4, -4R, -5AR, -5BR, -5R, -20R, -20AR, -20BR, -40, -40AR, -40R, -40BR, -50R, and -60 turbofan engines. These engines are fitted to various corporate jet models and some military jet trainers.

More information:

 

 

 

 

China orders Xian MA60 landing gear checks

An Okay Airways MA60 retracting the undercarriage afte takeoff (Photo: byeangel / CC:Bync-sa)

An Okay Airways MA60 retracting the undercarriage afte takeoff (Photo: byeangel / CC:Bync-sa)

The Civil Aviation Administration of China (CAAC) ordered landing gear checks of MA60 turboprop aircraft following recent incidents.

The Xian MA60, a Chinese manufactured 60-passenger turboprop airliner, was involved in two incidents in China in February 2013. On February 4, a Joy Air MA60 suffered a nose gear collapse on landing at Zhengzhou. Three weeks later, the crew of an Okay Airways MA60 aborted the approach due to unsafe gear indications. A safe landing was carried out at Shenyang.

These incidents prompted the CAAC to issue three airworthiness directives (AD’s) on the issue. The AD’s call for a revision of the Airplane Flight Manual and an inspection of the undercarriage and gear annunciation system for all aircraft that have logged more than 6400 takeoffs.

A total of 15 aircraft are affected by the measure. Five are operated by Joy Air and others by Okay Airways, Lao Airlines, Air Zimbabwe, TAM of Bolivia and aircraft that were operated in the Philippines by Zest Air

More information:

 

EASA issues emergency AD for Short 360 landing gear inspections

File photo of a Short 360 (photo: H.Ranter/ASN)

File photo of a Short 360 (photo: H.Ranter/ASN)

The European Aviation Safety Agency (EASA) issued an emergency airworthiness directive (AD) to prevent main gear collapse occurrences on Short 360 aircraft.

During investigation of an accident with a Short 360 aircraft, it was established that a main landing gear (MLG) wheel lever failure occurred, due to fatigue cracking. This was initiated by corrosion in the area between the wheel lever bore for the axle bushes and the outer surface of the axle bushes. The absence of cadmium protective treatment on the outer surface of the axle bush was cited as a primary cause of the corrosion and subsequent fatigue cracking.
A review of maintenance repair organisation (MRO) records for the affected Wheel Lever Unit (WLU) provided no tangible evidence that the repair bushes used had the necessary cadmium protective treatment applied. The MRO record review also identified a further three WLU that were lacking the cadmium protective treatment and were therefore susceptible to corrosion and fatigue cracking.
This condition, if not detected and corrected, could lead to failure of the WLU and collapse of the main landing gear, possibly resulting in damage to the airplane and injury to the occupants.
For these reasons, the emergency AD requires identification of the affected WLU and their replacement with serviceable parts.

More information:

 

Airbus A320 gear up landing accidents prompt tougher inspections

The right landing gear of flight 063 only partially extended. (photo: ANSV)

The right landing gear of flight 063 only partially extended. (photo: ANSV)

Two recent Airbus A320 gear up landing accidents in Italy prompted EASA to demand tougher inspections. At the same time, the Italian accident investigation board ANSV issued four safety recommendations to EASA.

ANSV is currently investigating two accidents involving Airbus A320 passenger planes at Roma-Fiumicino Airport (FCO) in 2013. On June 8 an Wizzair A320 encountered problems when the crew selected the gear down during the approach to Rome-Ciampino Airport.  The left main gear only partially extended and remained stuck. An emergency landing was carried out at Fiumicino Airport.

On September 29, an Airbus A320 operated by Alitalia developed similar problems, this time with the right main gear only partially extending on approach to Rome. This aircraft also made an emergency landing at Fiumicino Airport.

Preliminary investigation results of the Alitalia plane indicate that the right hand main gear actuator was jammed. An X-Ray analysis revealed the presence of heavy debris in the damping housing. A retaining ring was found ‘out of the design position’. An analysis of DFDR data showed that the undercarriage locked down without delay on previous flights. No fault messages were found.

Several airworthiness directives have been issued since a similar occurrence involving a United Airlines A319 at Newark in January 2010. EASA now issued a new AD that retained the requirements of EASA AD 2011-0069R1 and AD 2013-0132-E, which are superseded, but with reduced inspection intervals, and requires replacement or modification, as applicable, of the affected MLG door actuators as terminating action for the monitoring, repetitive checks and inspections.

At the same time, ANSV issued four safety recommendations to EASA. Amongst others, ANSV recommends EASA to require additional checks of the hydraulic system of the landing gear doors when replacing an actuator, to make sure that there is no contamination present. ANSV also recommends X-Ray inspections of actuators.

 

Emergency AD calls for Embraer Phenom 300 brake inspections

File photo of a Phenom 300 (photo: Rolf Wallner)

File photo of a Phenom 300 (photo: Rolf Wallner)

Brazilian authorities issued an Emergency Airworthiness Directive (EAD) regarding a  brake assembly inspection for Embraer Phenom 300 jets.

The Brazilian civil aviation agency Agência Nacional de Aviação Civil (ANAC) issued an Emergency Airworthiness Directive to inspect Embraer EMB-505 Phenom 300 corporate jets.
Embraer learned that cracks could occur in the stator pressure plate of the brake assembly of an airplane. This may lead to loss of brake parts on the runway, and to a reduced airplane brake capability with a possible runway excursion event.

The EAD calls for inspection of the airplane before the next flight after the effective date of the AD, which is September 26, 2013.

The AD does not state if the cracks were discovered during routine maintenance or during examination following a recent incident. On August 5, 2013, for instance, a Phenom 300 suffered a runway excursion on landing at Minneapolis-Flying Cloud Airport, MN (FCM).

More information: