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Canada issues Emergency AD to limit Airbus A220 engine power settings after recent incidents
28 October 2019

Canada issues Emergency AD to limit Airbus A220 engine power settings after recent incidents

Regulator Transport Canada issued an Emergency Airworthiness Directive (AD) to limit certain engine power settings on Airbus A220 aircraft following three recent failures.

Three inflight shutdowns occurred within three months time: July 25, 2019, September 16, 2019, and October 15, 2019. In all cases, the aircraft involved was a Swiss International Air Lines Airbus A220-300 (formerly named Bombardier CSeries 300) with Pratt & Whitney PW1524G-3 engines. These inflight shutdowns were due to failure of the low-pressure compressor (LPC) stage 1 rotor, which resulted in the rotor disk releasing from the LPC case and damaging the engine.

Investigations are ongoing to determine the root cause., but preliminary investigation results indicate high altitude climbs at higher thrust settings for engines with certain thrust ratings may be a contributor. This condition, if not corrected, could lead to an uncontained failure of the engine and damage to the aeroplane.
Transport Canada issued the AD on October 26, introducing a new Aircraft Flight Manual (AFM) limitation and normal procedure to limit the engine N1 setting to 94% while above 29000 feet. This AD is considered an interim action and further AD action may follow.


FAA issues emergency AD on GE90-115B turbofan engines following uncontained failure incident

The FAA issued an emergency Airworthiness Directive (AD), ordering the removal of a seal from certain General Electric GE90-115B turbofan engines.

The emergency AD was prompted by an incident that occurred on October 20, 2019, in which a Thai Airways Boeing 777-300ER airplane powered by GE GE90-115B turbofan engines experienced an uncontained high-pressure turbine (HPT) failure that resulted in an aborted takeoff. Debris impacted the aircraft fuselage and the other engine.

The AD calls for the removal from service of the Interstage Seal of certain GE GE90-115B turbofan engines, within 25 flight cycles.


Airbus A220 PW1500G engine failures prompt inspection AD

The FAA issued an airworthiness directive (AD), requiring initial and repetitive inspections on certain Pratt & Whitney geared turbofan engines following two recent incidents.

The first inflight shutdown occurred on July 25, 2019 and the second occurred on September 16, 2019. In both cases, the aircraft involved was a Swiss International Air Lines Airbus A220-300 with Pratt & Whitney PW1524G-3 engines.
These inflight shutdowns were due to failure of the low-pressure compressor (LPC) stage 1 rotor, which resulted in the rotor disk releasing from the LPC case and damaging the engine.

To prevent recurrences, the FAA requires initial and repetitive borescope inspections of the LPC inlet guide vane (IGV) and the LPC stage 1 rotor and, depending on the results of the inspections, replacement of the LPC.

Although these incidents occurred on PW1524G-3 model turbofan engines, the FAA is including PW1900 engines because similarities in type design make these engines susceptible to the same unsafe condition. The required inspections have to be performed within 50 flight cycles from September 26, and thereafter at intervals not to exceed 50 flight cycles until the engine accumulates 300 flight cycles.

The investigation into both incidents has been delegated to the NTSB.

Parts from the low-pressure compressor stage 1 rotor in the July 25 incident

CASA Australia and EASA lift grounding of GA-8 Airvan

Australian and European regulators decided to lift the grounding of the GA8 Airvan.

The grounding came into effect on July 20, following a fatal accident on 14 July 2019, when a GA8 Airvan skydiving plane crashed in Sweden. At 4000 meters altitude, the aircraft suffered a separation of a wing.

Since the emergency AD was issued, CASA Australia informed EASA that the results of the physical inspection of the accident aircraft indicate that it appears to have been exposed to aerodynamic loads beyond those for which the type design is certificated.

No evidence was found to indicate that an unsafe condition exists or could develop that would warrant further grounding.

CASA Australia and EASA ground GA-8 Airvan following a recent accident in Sweden

Australian and European regulators decided to ground the GA8 Airvan following a recent accident.

On 14 July 2019, a fatal accident occurred with a GA8 Airvan skydiving plane in Sweden. Indications are that the aircraft, at 4000 meters altitude, suffered structural failure. Early reports are that a wing may have detached prior to the accident, but, at this time, the root cause of the accident cannot be confirmed.
CASA Australia, the authority of the State of Design of the affected type design, has informed EASA that a Direction will be issued, which provides for the temporary prohibition of operations of the GA8 Airvan in Australia. The Direction will take effect on 20 July 2019 and will be valid for 15 days. Based on all available information, and taking into account the Australian Direction, EASA has
decided to ground the affected aeroplanes registered in EASA Member States, until further notice.
The emergency AD 2019-0177-E is considered an interim action and further AD action may follow.

File photo of a GA8 Airvan (c) H. Ranter


FAA: Some Boeing 737NG and MAX aircraft may have improperly manufactured leading edge slat tracks

Boeing has informed the FAA that certain 737NG and 737MAX leading edge slat tracks may have been improperly manufactured and may not meet all applicable regulatory requirements for strength and durability.

Following an investigation conducted by Boeing and the FAA Certificate Management Office (CMO), the FAA determined that up to 148 parts manufactured by a Boeing sub-tier supplier are affected. Boeing has identified groups of both 737NG and 737MAX airplane serial numbers on which these suspect parts may have been installed. 32 NG and 33 MAX are affected in the U.S. Affected worldwide fleet are 133 NG and 179 MAX aircraft.

The affected parts may be susceptible to premature failure or cracks resulting from the improper manufacturing process. Although a complete failure of a leading edge slat track would not result in the loss of the aircraft, a risk remains that a failed part could lead to aircraft damage in flight, the FAA stated.

The FAA will issue an Airworthiness Directive to mandate Boeing’s service actions to identify and remove the discrepant parts from service. Operators of affected aircraft are required to perform this action within 10 days. The FAA today also alerted international civil aviation authorities of this condition and required actions.

Upset incidents lead EASA to issue emergency AD on CitationJets with active winglets

The European Union Aviation Safety Agency (EASA) issued an emergency airworthiness directive (2019-0086-E) in the wake of recent in-flight upset incidents involving Cessna CitationJets, modified to have Tamarack ATLAS winglets.

The active load alleviation system (ATLAS), when operational, deflects the Tamarack active control surfaces (TACS) on the outboard wings. This system can aerodynamically “turn off” the winglet in specific conditions, thus dumping additional loads. Load alleviation enables a substantial increase in aspect ratio without the need for wing reinforcement and added weight, according to Tamarack. The modification is available for Cessna CitationJet models.

Recently, occurrences have been reported in which ATLAS appears to have malfunctioned, causing upset events where, in some cases, the pilots had difficulty to recover the aircraft to safe flight. Investigation continues to determine the cause(s) for the reported events. This condition, if not corrected, could lead to loss of control of the aircraft, EASA states.

The AD issued by EASA requires the Tamarack ATLAS to be deactivated and the TACS to be fixed in place. It also requires implementation of operational limitations and repetitive pre-flight inspections by amending the applicable flight manual.

Within 100 flight hours, owners must contact the ATLAS-manufacturer for modification instructions.

Update 11 July 2019
Both EASA and the FAA approved fixes incorporated in two Tamarack Aerospace service bulletins to resolve the emergency airworthiness directive that required deactivating Tamarack’s active load-alleviation system (ATLAS) on Cessna CitationJets.


FAA demands replacement of AOA sensors on Cirrus SF50 jets following incidents

On April 18 the FAA published an emergency airworthiness directive (2019-08-51), requiring replacement of the angle of attack (AOA) sensor with an improved model.

This AD was prompted by Cirrus reporting three incidents of the stall warning and protection system (SWPS) or Electronic Stability & Protection (ESP) System engaging when not appropriate.
The SWPS and ESP may engage even when sufficient airspeed and proper angle of attack (AOA) exists for normal flight. SWPS includes the stall warning alarm, stick shaker and stick pusher. ESP includes under speed protection (USP). The SWPS and ESP engaging could potentially result in a STALL WARNING crew alert (CAS) message activation, accompanied by an audio alarm and stick shaker activation, followed possibly by either low speed ESP/USP engaging and/or the stick pusher engaging. The pilot will also observe the dynamic and color-coded (Red) airspeed awareness ranges displaying the stall band, regardless of actual indicated airspeed. These conditions, if not addressed, could result in the flight crew having difficulty controlling the airplane, lead to excessive nose-down attitude, significant altitude loss, and possible impact with terrain.

Cirrus and Aerosonic (manufacturer of the technical standard order AOA sensor) have identified the probable root cause as an AOA sensor malfunction due to a quality escape in the assembly of the AOA sensor at Aerosonic. Two set screws that secure the potentiometer shaft to the AOA vane shaft may have improper torqueing and no application of thread locker (Loctite) to secure the two set screws.

Before further flight, AOA sensor must be replaced before further flight.  Operators may fly the airplane to a location where the modification/corrective action can be incorporated using a special flight permit.

FAA issues emergency AD regarding potential erroneous AOA input on Boeing 737 MAX

On November 7, the U.S. FAA issued an emergency Airworthiness Directive (AD 2018-23-51) regarding the potential for erroneous angle of attack input.

The AD, and an earlier Boeing FCOM Bulletin on the matter, was prompted by initial findings in the investigation into the cause of the crash of Lion Air flight JT610 on October 29, 2018. The Indonesian NTSC revealed that the aircraft experienced erroneous input from one of its AOA (Angle of Attack) sensors.

The FAA AD now requires “revising certificate limitations and operating procedures of the airplane flight manual (AFM) to provide the flight crew with runaway horizontal stabilizer trim procedures to follow under certain conditions.”

On November 6, 2018, Boeing issued an Operations Manual Bulletin (OMB) directing operators to existing flight crew procedures to address circumstances where there is erroneous input from an AOA sensor. (Boeing statement)


FAA issues AD for ultrasonic inspection for cracks in HPT stage 1 and stage 2 disks on CF6-80 engines

The U.S. Federal Aviation Administration (FAA) issued an Airworthiness Directive, requiring airlines to perform an ultrasonic inspection for cracks in High-Pressure Turbine (HPT) stage 1 and stage 2 disks on certain CF6-80 engines.

The AD, was published in the wake of the uncontained engine failure accident involving American Airlines flight 383 at Chicago-O’Hare International Airport on 28 October 2016. The aircraft, a Boeing 767-300ER suffered an experiencing an uncontained General Electric CF6-80C2 engine failure during takeoff. A fire erupted and consumed a large part of the wing. All 170 occupants survived.

Stage 2 high pressure turbine disk of AA383