January 20, 2012
The European Aviation Safety Agency (EASA) issued an Airworthiness Directive (AD), ordering inspection of certain Airbus A380 aircraft for the possible presence of cracks in the wing rib feet.
The AD states:
Following an unscheduled internal inspection of an A380 wing, some rib feet have been found with cracks originating from the rib to skin panel attachment holes (Type 1 cracks according to Airbus All Operator Telex (AOT) terminology).
Further to this finding, inspections were carried out on a number of other aeroplanes where further cracks have been found. During one of those inspections, a new form of rib foot cracking originating from the forward and aft edges of the vertical web of the rib feet has been identified (Type 2 cracks according to Airbus AOT terminology). The new form of cracking is more significant than the original rib foot hole cracking. It has been determined that the Type 2 cracks may develop on other aeroplanes after a period of time in service.
This condition, if not detected and corrected, could potentially affect the structural integrity of the aeroplane.
For the reasons described above, this AD requires a Detailed Visual Inspection (DVI) of certain wing rib feet. This AD also requires reporting the inspection results to Airbus.
This AD is considered to be an interim action to immediately address this condition. As a result of the on-going investigation, further mandatory actions might be considered.
The cracks were discovered by Airbus engineers while performing repair work to a Qantas A380 that had suffered an uncontained engine failure near Singapore’s Changi Airport. Singapore Airlines also discovered some cracks in on the L-shaped feet of the wing ribs. The feet attach the rib, a vertical fixture, to the cover of the wing.
On January 9th a spokesman for the Australian Licensed Aircraft Engineers Association demanded that all A380 aircraft should be grounded for inspections. Airbus reported that all planes were safe to fly and that the cracks did not pose a safety threat.
August 3, 2011
The European Aviation Safety Agency (EASA) is proposing an Airworthiness Directive for an Airbus A330/A340 Flight Control Primary Computer (FCPC) software update in the wake of the fatal accident involving Air France flight AF447.
EASA states that it has been determined that, when there are significant differences between all airspeed sources, the flight controls of an Airbus A330 or A340 aeroplane will revert to alternate law, the autopilot (AP) and the auto-thrust (A/THR) automatically disconnect, and the Flight Directors (FD) bars are automatically removed.
Further analyses have shown that, after such an event, if two airspeed sources become similar while still erroneous, the flight guidance computers will display the FD bars again, and enable the re-engagement of AP and A/THR. However, in some cases, the AP orders may be inappropriate, such as possible abrupt pitch command.
In order to prevent such events which may, under specific circumstances, constitute an unsafe condition, EASA issued AD 2010-0271 to require an amendment of the Flight Manual to ensure that flight crews apply the appropriate operational procedure.
Since that AD was issued, new FCPC software standards have been developed that will inhibit autopilot engagement under unreliable airspeed conditions. The proposed AD requires software standard up-grade of the three FCPCs by either modification or replacement. The Proposed AD will be open for consultation until 30 August 2011.
July 25, 2011
Transport Canada issued an emergency airworthiness directive regarding wing to fuselage attachment joints on DHC-8-400 aircraft models.
Transport Canada reports that there have been three in-service reports of cracked barrel nuts found at the front spar locations of the wing to fuselage attachment joints. Additionally, three operators have reported finding a loose washer in the barrel nut assembly. Failure of the barrel nuts could compromise the structural integrity of the wing to fuselage attachments.
Preliminary investigation determined that these cracks are due to hydrogen embrittlement.
The AD mandates an initial and repetitive detailed inspection of the barrel nuts. The AD applies to all DHC-8 aeroplane models 400, 401 and 402, serial numbers 4001 and subsequent that have accumulated 1900 or more total hours air time or 12 months or more in service since new
June 30, 2011
The European Aviation Safety Authority (EASA) issued an emergency Airworthiness Directive (AD) effecting specific Airbus A330 and A340-200/-300 aeroplanes. EASA requires reduction of the existing main landing gear (MLG) bogie beam life limits and replacement of each MLG bogie beam that has already exceeded the new limit.
During ground load test cycles on an A340-600 aeroplane, the MLG bogie beam prematurely fractured.
The results of the investigation identified that this premature fracture was due to high tensile standing stress, resulting from dry fit axle assembly method.
Improvement has been introduced subsequently with a grease fit axle assembly method.
Analysis was performed on other bogie beam with dry fit axles. It has been determined that MLG bogie beams with specific part numbers are more likely to suffer from standing stress generated by dry-fit axles because these bogie beams are stiffer between the axle sockets. These two part numbers are fitted on A330, A340-200 and -300 series aircraft.
Fracture of a MLG bogie beam under high speed could ultimately result in the aeroplane departing the runway, or in the bogie detaching from the aeroplane, or MLG collapse, which could cause structural damage to the aeroplane and injury to the occupants.
June 17, 2011
A Dassault-owned Falcon 7X arrives at Rotterdam Airport (EHRD) on the day following the lifting of the ban (Photo: Harro Ranter, 17 June 2011)
On May 26, 2011 all flights involving Dassault Falcon 7X jets were prohibited following the EASA’s issuance of emergency AD 2011-0102-E. This suspension is now lifted for certain aircraft as of June 16, 2011.
The suspension of flight operations was considered to be an interim measure pending the outcome of an investigation into a serious incident involving an uncontrolled pitch trim runaway during descent.
The initial results of the investigations are showing that there was a production defect in the Horizontal Stabilizer Electronic Control Unit (HSECU) which could have contributed to the cause of the event. One specific HSECU is potentially affected by this production defect. Investigations are continuing to confirm this cause.
In the meantime, to allow re-starting flight operations and providing protection against further pitch trim runaway events, Dassault Aviation have developed two modifications which are implemented through accomplishment of Dassault Service Bulletin (SB) F7X-211. In addition, it has determined that the flight envelope must be restricted, compared to the original certified flight envelope.
For aeroplanes equipped with HSECU P/N 051244-02, this AD, which supersedes EASA AD 2011-0102-E, requires:
- accomplishment of two Dassault Aviation modifications,
- amending the AFM and installing a placard in the cockpit,
- amending the Minimum Equipment List (MEL), and
- implementing an operational test of the HSTA electric motors reversion relays.
For aeroplanes equipped with HSECU P/N 051244-04, the prohibition of flights is maintained.
Download PDF: EASA EAD 2011-0114-E
May 26, 2011
A Falcon 7X jet (photo: Jerome K. /CC: by-nc-nd)
The European Aviation Safety Agency (EASA) issued an Emergency Airworthiness Directive (AD), prohibiting flight operations of Dassault Falcon 7X jets.
The AD is considered to be an interim measure pending the outcome of an investigation into a serious incident currently carried out by the manufacturer. Further AD action is expected to follow when additional information is available.
The incident involved a Falcon 7X which experienced an uncontrolled pitch trim runaway during descent. The crew succeeded in recovering a stable situation and performed an uneventful landing. Analysis of the Digital Flight Data Recorder (DFDR) and Fault History Database (FHDB) confirmed the event, but did not allow explaining the origin of the pitch trim runaway.
This condition, if occurring again, could lead to loss of control of the aeroplane. To address this potential unsafe condition, Dassault Aviation has proposed to EASA to prohibit, from the effective date of this AD, any flight operations of Falcon 7X aeroplanes, to which EASA agreed by issuing this AD.
April 5, 2011
The U.S. FAA issues an emergency directive that will require operators of specific early Boeing 737 models to conduct initial and repetitive electromagnetic inspections for fatigue damage. This action will initially apply to a total of approximately 175 aircraft worldwide, 80 of which are U.S.-registered aircraft. Most of the aircraft in the U.S. are operated by Southwest Airlines.
The FAA airworthiness directive will require initial inspections using electromagnetic, or eddy-current, technology in specific areas of the aircraft fuselage on certain Boeing 737 aircraft in the -300, -400 and -500 series that have accumulated more than 30,000 flight cycles. It will then require repetitive inspections at regular intervals.
In November 2010, the FAA published a rule designed specifically to address widespread fatigue damage in aging aircraft. The rule requires aircraft manufacturers to establish a number of flight cycles or hours a plane can operate and be free from fatigue damage. The rule requires aircraft manufacturers to incorporate the limits into their maintenance programs.