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FAA AD on gust lock modification on Gulfstream G-IV jets becomes effective
2 August 2017

FAA AD on gust lock modification on Gulfstream G-IV jets becomes effective

The G-IV accident that prompted the AD (NTSB)

An FAA Airworthiness Directive (AD) is becoming effective on August 3, 2017, calling for a retrofit of the gust lock throttle interlock on specific Gulfstream G-IV, G300 and G400 jets. This AD follows a fatal accident in 2014.

On May 31, 2014 a Gulfstream G-IV corporate jet was destroyed in a takeoff accident at Bedford-Hanscom Field, Massachusetts, USA. All four passengers and three crew members were killed.
During the engine start process, the flight crew neglected to disengage the airplane’s gust lock system, which locks the elevator, ailerons, and rudder while the airplane is parked to protect them against wind gust loads. Further, before initiating takeoff, the pilots neglected to perform a flight control check that would have alerted them of the locked flight controls. During takeoff the flight crew noticed that the controls were locked. The aircraft overran the runway, struck lights and came to rest in a gully.

The G-IV is equipped with a mechanical interlock between the gust lock handle and the throttle levers that restricts the movement of the throttle levers when the gust lock handle is in the ON position. This interlock mechanism was intended to limit throttle lever movement to a throttle lever angle (TLA) of no greater than 6° during operation with the gust lock on. However, postaccident testing on nine in-service G-IV airplanes found that, with the gust lock handle in the ON position, the forward throttle lever movement that could be achieved on the G-IV was 3 to 4 times greater than the intended TLA of 6°.

This caused the NTSB to issue a Safety Recommendation (A-15-31) in September 2015, addressed to the FAA:

After Gulfstream Aerospace Corporation develops a modification of the G-IV gust lock/throttle lever interlock, require that the gust lock system on all existing G-IV airplanes be retrofitted to comply with the certification requirement that the gust lock physically limit the operation of the airplane so that the pilot receives an unmistakable warning at the start of takeoff.

A notice of proposed rulemaking (NPRM) was published by the FAA in December 2016, resulting in the AD to be published June 29, 2017. This AD now becomes effective.

Operators must, within 36 months, modify the gust lock system by doing a retrofit of the gust lock throttle interlock, in accordance with the Accomplishment Instructions provided by Gulfstream.

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EASA issues emergency AD for stabilizer inspection of Sukhoi Superjet aircaft

The European Aviation Safety Agency (EASA) issued an emergency airworthiness directive, requiring inspection of the horizontal stabilizer for cracks.

EASA reported that cracks were found on Sukhoi Superjet 100-95B aeroplanes in service in the rear spar of the horizontal stabilizer between ribs 0, 1 and 2.

The AD requires operators to accomplish a borescope inspection of the horizontal stabilizer rear spar web cut-out between ribs 0-1 and 1-2 before exceeding 1300 flight cycles since first flight, or before July 29, whichever occurs later. Thereafter, the inspection must be repeated at intervals not to exceed 300 flight cycles.

Should an operator detect any crack, fastener failure, or corrosion, it must contact Sukhoi Civil Aircraft before next flight, for approved repair instructions.

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Authorities ground Sukhoi Superjets for inspections

File photo of an Aeroflot Superjet 100-95 (photo: Dmitry Zherdin / CC:by-sa)

Russian authorities grounded all Sukhoi Superjet aircraft for mandatory inspections after cracks were found at stabilizer attachment points.

In an Airworthiness Directive, the Russian Federal Air Transport Agency reported that during the maintenance of Sukhoi Superjet 100-95B aircraft serial No. 95018, tail No. RA-89010, cracks were detected in the lugs of the stabilizer upper and lower bracket attachment bands.

Operators are instructed to perform an inspection of the stabilizer bracket attachment bands prior to departures from the base airports of the RRJ-95 aircraft.

RA-89010 is one of 104 Superjets that have been delivered to date. RA-89010 first flew in July 2012 and operates for IrAero since July 2016.

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FAA orders engine icing fixes for GEnx-powered Boeing 787 Dreamliners

The incident aircraft, JA822J at Vancouver, 18 April 2015 (photo: Eric Salard / CC:by-sa)

The incident aircraft, JA822J at Vancouver, 18 April 2015 (photo: Eric Salard / CC:by-sa)

The U.S. Federal Aviation Administration (FAA) issued a new airworthiness directive (AD) to reduce the likelihood of engine damage due to fan ice shedding on certain Boeing 787 Dreamliner aircraft powered by GEnx-1B engines.

On March 14, 2016, the FAA already issued AD 2016-06-08 which was prompted by an incident on 29 January 2016.
A Japan Airlines Boeing 787-8 Dreamliner, operating as JL17 from Vancouver, Canada to Tokyo/Narita, Japan, was at 140 km east of Narita when the No.2 engine had to be shut down.
Partial fan ice shedding resulted in fan imbalance that in turn caused substantial damage to the engine and an in-flight non-restartable power loss. The engine involved was a General Electric GEnx-1B()/P2.
The engine damage appears to be a result of susceptibility to heavy fan blade rubs common to the GEnx-1B PIP2 engine. The other engine on the event airplane was an older design GEnx-1B PIP1 configuration that incurred expected wear and minor damage during the icing event and continued to operate normally. The event occurred in icing conditions at an altitude of 20,000 feet.
The urgency of this issue stems from the safety concern over continued safe flight and landing for airplanes that are powered by two GEnx-1B PIP2 engines operating in a similar environment to the event airplane. In this case both GEnx-1B PIP2 engines may be similarly damaged and unable to be restarted in flight. The potential for common cause failure of both engines in flight is an urgent safety issue.

This AD (AD 2016-08-12) requires revising the AFM to provide the flight crew a revised fan ice removal procedure and a new associated mandatory flight crew briefing to reduce the likelihood of engine damage due to fan ice shedding. For an airplane with two GEnx-1B PIP2 engines having specified model and part numbers, this AD also requires reworking or replacing at least one engine.

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FAA proposes AD to prevent turbine hub failures on IAE jet engines

The FAA proposes to issue an Airworthiness Directive (AD)  to prevent high-pressure turbine hub failures on certain IAE jet engines, which could result in uncontained blade release, damage to the engine, and damage to the airplane.

The AD was issued in the wake of an incident that occurred on 18 September 2014. An Airbus A320-232, JetBlue flight number 1416, powered by two International Aero Engines (IAE) V2527-A5 turbofan engines, experienced a No. 2 (right) engine failure and subsequent undercowl fire during initial climb after departing Long Beach Airport (LGB), California. The flightcrew shutdown the No. 2 engine, discharged both fire bottles, and performed an air turnback to Long Beach. The airplane made a successful and uneventful single-engine landing at Long Beach Airport.

The NTSB determined the probable cause of the engine failure and subsequent undercowl engine fire was due to the fatigue fracture of a high pressure turbine stage 2 disk blade retaining lug that released two blades which impacted the low pressure turbine case causing a fuel line to fracture spraying fuel on the hot engine cases where it ignited. During a machining operation of the disk lug, a tool mark was introduced that set up the area for fatigue cracks to initiate.

The FAA determined the unsafe condition is likely to exist or develop in other products of the same type design. Consequenty a Notice Of Proposed Rulemaking (Nprm) was issued, asking relevant parties to respond to the proposed AD by June 6, 2016.

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FAA issues Airworthiness Directive following airspeed anomalies on Boeing 787 Dreamliners

The FAA issued an Airworthiness Directive (AD), warning Boeing 787 Dreamliner pilots not to use abrupt control inputs in case of erroneous airspeed indications.

The FAA states it has received three reports of in-service displayed airspeed anomalies on Boeing 787 Dreamliner airplanes. While further investigation is ongoing, the anomalous behavior is consistent with significant water ingestion or simultaneous icing of two or three of the three pitot probes. During each of the reported events, the displayed airspeed rapidly dropped significantly below the actual airplane airspeed. In normal operations, the air data reference system supplies the same airspeed to both the captain and first officer primary flight displays. During one in-service event, with autopilot engaged, the pilot overrode the engaged autopilot in response to the displayed erroneous low airspeed and made significant nose-down manual control inputs. In this situation, there is the potential for large pilot control inputs at high actual airspeed, which could cause the airplane to exceed its structural capability.

The AD, for all Boeing 787-8 and 787-9 airplanes, calls for a revision of the airplane flight manual (AFM) to instruct the flightcrew to avoid abrupt flight control inputs in response to sudden drops in airspeed, and to reinforce the need to disconnect the autopilot before making any manual flight control inputs.

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Brazil issues emergency AD on Phenom 300 anti-icing equipment

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

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

Brazilian authorities, ANAC, issued an Emergency Airworthiness Directive (EAD) requiring inspection of a wing anti-icing element on Phenom 300 jets.

The Emergency AD resulted from a report of an incorrect installation of the wing leading edge anti-ice piccolo tube. Incorrect installation of this tube could result in ice accretion on the wing leading edges and consequent loss of control of the airplane. ANAC judged that this condition might exist in other Phenom 300 jets.
Consequently an Emergency AD was issued. requiring inspection and correction of discrepancies in the installation of the piccolo tube of the left hand and right hand outboard wing leading edges.

The piccolo tubes route hot bleed air from the engines  through wings, tail surfaces, and engine inlets to keep the flight surfaces above the freezing temperature.

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Canada issues emergency AD requiring inspection of flap fasteners on Challenger jets

File photo of a Challenger 601 (H.Ranter/ASN)

File photo of a Challenger 601 (H.Ranter/ASN)

Transport Canada issued an emergency airworthiness directive (AD), requiring operators of specific Canadair Challenger 600, 601, 601-3A/3R aircraft to inspect inboard flap fasteners.

According to the AD, there have been three in-service reports on Challenger 604 Variant aircraft of a fractured fastener head on the inboard flap hinge-box forward fitting at Wing Station (WS) 76.50, which were found during a routine maintenance inspection.
Investigation revealed that the installation of these fasteners on the inboard flap hinge-box forward fittings at WS 76.50 and WS 127.25, on both wings, does not conform to the engineering drawings. Incorrect installation may result in premature failure of the fasteners attaching the inboard flap hinge-box forward fitting. Failure of the fasteners could lead to the detachment of the flap hinge box and consequently the detachment of the flap surface. The loss of a flap surface could adversely affect the continued safe operation of the airplane.

On August 15, 2014, an AD had been issued, mandating a detailed visual inspection (DVI) of each inboard flap hinge-box forward fitting, on both wings, and rectification as required. Incorrectly oriented fasteners require repetitive inspections until the terminating action is accomplished.
After the issuance of the original AD, there has been one reported incident on a Challenger 604 where four fasteners were found fractured on the same flap hingebox forward fitting. The investigation determined that the fasteners were incorrectly installed. Although there have been no reported fractured fastener heads found to date on any model Challenger 600, 601, 601-3A/3R aircraft , incorrectly oriented fasteners were found on some of these models.

The AD requires repeated inspections until the fasteners have been replaced.

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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.

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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.

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