Fixed Wing

AIRBUS, A310 304
SDR # 20101223006
Flight Spoiler PCU Rod End Failure

SDR submitted:

During flight, a R/H spoiler panel began to float freely where maintenance discovered the #2 R/H Spoiler Actuator threaded rod end assembly had failed and separated from its adjoining PCU housing.

Prior to this finding on the previous flight, a Minimum Equipment List (MEL) deferral for a #2 & #3 spoiler fault was applied and the aeroplane was dispatched.

The flight spoiler PCU actuator was replaced, MEL removed and the aeroplane was made serviceable.

Transport Canada Comments:
The information on this finding has been forwarded to Airbus for further investigation.

Transport Canada Civil Aviation (TCCA) would like to remind all operators of the importance to ensure for correct aircraft system integrity prior to applying MEL deferrals. Hammer and wrench in X formation indicating end of article

PCU Rod End | PCU Actuator Housing

BAE - UK, 3112
SDR # 20101028003
Passenger Door Seat Retainer Corrosion

SDR submitted:

The aeroplane passenger door seal had a small tear in it causing a pressurization leak. Upon maintenance inspection when the door seal was removed, corrosion was noted.

A further inspection found extensive corrosion through the skin with a width of 2.5 cm (1 in) by 1.27 cm (1/2 in) on the top of the door seal retainer under the seal.

A repair was carried out, the corrosion removed and the aircraft was made serviceable.

Transport Canada Comments:
BAE United Kingdom being the Type Certificate Holder (TCH) of this aircraft and as noted from the operator, have issued Information Letter 52-J31-J32-664-1 and revised the maintenance program to define a more specific inspection task for the passenger door.

Transport Canada Civil Aviation (TCCA) would like to advise all owners and operators of this aeroplane model to be aware of this possible corrosion and BAEs corrective action to address this issue. Hammer and wrench in X formation indicating end of article

Passenger Door Seat Retainer Corrosion

SDR # 20110506002
Elevator Auto Pilot Servo Drum - Frozen

SDR submitted:

The aeroplane was parked outside overnight in the rain. The following day while flying at FL240 (24 000 feet) the pilot received an auto-pilot (A/P) “disconnect” annunciation. The pilot then manually took control and noted a slight resistance of the elevator control inputs.

Prior to next flight, maintenance personnel gained access to the tail section and found the elevator auto pilot servo cable drum coated with ice. It was apparent that the rain (the previous night) had drained down onto the stabilizer and then migrated onto the cable drum. During flight the next day at 24 000 feet, ice formed on the A/P cable drum and caused resistance of the elevator controls.

The operator stated that this was the 2nd occurrence of this nature.

Transport Canada Comments:
Transport Canada Civil Aviation wish to remind owners and operators to hangar their aeroplane (whenever possible) during rainy conditions. Any interference of the primary or secondary flight controls can jeopardize the safety of the flight
. Hammer and wrench in X formation indicating end of article

SDR # 20091002006
Engine High Pressure Fuel Leak

SDR submitted:

The pilot noticed a fuel leak during preflight inspection. Maintenance personnel removed the engine cowling and cleaned the residual fuel from the immediate area. When the engine was being run-up to check for fuel leaks, it was then noted that a high-pressure fuel spray was coming from a fuel line that attaches from the engine pylon area to the hydromechanical fuel unit. The fuel spray was contacting the back of one of the engine igniters. Fortunately, the engine was immediately shutdown without a major fire.

The defective fuel line was replaced, however there was no chafing or wear damage evident.

Transport Canada Comments:
A search of the SDR database revealed several previous reports of this engine motive fuel line being chaffed and damaged by contacting the adjacent cowl latch.

The power plant installed on this aeroplane has tight clearances; therefore it is recommended that adequate distance between lines, tubings, cables and wires be adhered to. Hammer and wrench in X formation indicating end of article

BOEING, 727 227
SDR # 20110225009
Cargo Door Hydraulic Leak

SDR submitted:

A hydraulic fluid leak was identified when closing the main cargo door. Maintenance investigation identified hydraulic fluid leaking from the cargo door manifold assembly at the check-valve body due to a circumferential and through crack.

The manifold assembly was replaced, a leak and function check carried out and the aircraft was made serviceable.

Transport Canada Comments:
The check-valve cylindrical body, which is mounted to the manifold assembly, has two “Hex wrenching” flat surfaces. One near its base used specifically to mount it to the manifold and a second one at the attachment of the hydraulic line, used for line attachment support.

It is suspected that the hydraulic line was torque during installation without the use and support of the check-valves Hex wrenching surface, stressing its cylindrical body and causing its failure.

Transport Canada Civil Aviation (TCCA) would like to advise all maintainers the importance in understanding these design features and maintenance practices for the correct installation of hydraulic components. Hammer and wrench in X formation indicating end of article

Hex Wrenching Flat Surface

SDR # 20110119003
CFM56-7B Engine Check Valve Failure

SDR submitted:

During descent with the auto-throttle (a/t) engaged, the flight crew encountered a left engine surge and intermittent stalls. The crew disengaged the a/t and using manual throttle inputs, were able to sufficiently control the engines tendency to surge.

The engines parameters remained normal during descent and made an uneventful landing. During maintenance taxi to the hangar, the left engine fuel flow was fluctuating slowly between 700 and 800 lbs/hr. When the thrust levers were advanced slightly, the left engine started to shake and vibrate with subsequent annunciation of an engine fail message and an automatic engine shut down occurred.

Maintenance personnel accomplished FIM 71-05 task 805 and subsequently found the 5th stage compressor check valve stuck open. The valve was replaced as the corrective action and the aeroplane was returned to service.

Transport Canada Comments:
It is important for maintenance personnel to recognize the characteristics of a failed engine compressor check valve to prevent further engine surging.
Hammer and wrench in X formation indicating end of article

CFM56-7B Engine Check Valve Failure

Broken Flange Bushing

SDR # 20110212001
Slat Drive Shaft Loose Screws

SDR submitted:

While removing the right engine pylon during a scheduled event, maintenance found a left-hand wing leading edge flap drive shaft coupling sleeve, at wing station 468, with loose attaching screws due to missing lockwire.

The attaching screws were re-torqued and lockwired as per Aircraft Maintenance Manual (AMM) 27-81-05 & 27-52-09.

Upon this finding, the operator proceeded to inspect its remaining Boeing 747 fleet of all leading edge flap drive shaft couplings and trailing edge flap torque tube couplings to ensure for proper installation and safety in accordance with the AMM.

Transport Canada Comments:
All aeroplane attaching hardware incorporate a form of lock or safety to ensure that the applied torque is kept through the life of the fasteners installation.

Lockwire is one of several methods used to perform this important and essential function. Hammer and wrench in X formation indicating end of article

Slat drive-shaft torque tube coupling screw found loose (gap under head) due to no lockwire installed

BOEING, 757 28A
SDR # 20101206015
Pylon Panel Missing

SDR submitted:

On arrival after a flight, it was noticed that inspection panel 443BR on the outboard side of the right engine pylon was missing. Panel part number (P/N) 311n5049-139, IPC 54-53-01-05, item 175. The panel was replaced and the aeroplane was made serviceable.

Transport Canada Comments:
A similar event had occurred previously with this operator and an internal investigation was done through their standard Safety Management System (SMS) process.

The results defined the root cause of the events as being induced through the improper installation of the panel.

Boeing AMM 54-53-01 defines the correct panel “latch indicator groove” alignment as seen below for a “closed/locked” and “open/unlocked” position.

Also included is a picture of the backside of the panel as seen in the “closed/locked” position. Note that the “groove indicator” marks are a direct indication of the rotating latch position which retains the panel to the pylon structure. Hammer and wrench in X formation indicating end of article

Panel Assy 311N5049-139
Rotating Latch In Locked Position – Points to Edge of panel
Normal operation: To open - loosen screw until the rotating latch rotates to the open position. To close - tighten screw causing the rotating latch to rotate to the locked position and continue to tighten screw to draw the rotating latch tight to the structure.

Boeing 757 Aircraft Maintenance Manual
Rotary Latch Closed
Strut Skin | Skin Doubler | Latch Bolt | Access Door | Latch Indicator Grooves
Rotary Latch Open
Latch Indicator Groove

SDR # 20101130004
Global Express Secondary Power Center Stud Burn

SDR submitted:

The flight crew reported that the multi-functional display (MFD) unit 1 went blank. APU would not start and after engine start, “DCU A OFF”, Flaps Fail, Fire Sys. Fault, Inboard Brakes Fail, L/H IAPS Fail, Pack Fail, Cabin Pressure Fault, FDR Fail, R/H Eng. Thrust Fault, R/H Eng. Fault, RDC Fault and MFD XTALK Fail messages appeared. MFD 1 and 2 swapped and the failure condition remained on the same side. There were no electrical fault CAS messages except for the DAU A circuit-breaker (CB) had tripped.

Two bus bars (ESS bus) were confirmed with no power and the battery connections were verified all good. On visual inspection of the L/H Secondary Power Center (SPC), the T1 wire-lead and stud was confirmed as badly burnt and melted.

The SPC was replaced and the aeroplane was made serviceable.

Transport Canada Comments:
Electrical faults are difficult to trouble-shoot and identify due to the system complexity and, as in this case, multiple cascading fault messages can be generated.

Wiring stud torque values are essential for the continuous and correct operations of all electrical systems.

Transport Canada Civil Aviation (TCCA) would like to emphasize to all operators and maintainers, the importance of correct wiring installation torque values of wire lead stud attachment points. Hammer and wrench in X formation indicating end of article

Global Express Secondary Power Center Stud Burn

SDR # 20110110011
Global Express NLG Trunion End-Cap O-Ring Pinched

SDR submitted:

During an unscheduled maintenance task, a technician noticed grease migrating into the nose fuselage underfloor area, between fuselage station (FS)  202 and 280, from a nose landing gear trunnion bearing end-cap.

Maintenance investigation revealed that the bearing caps recessed O-ring was improperly installed and found pinched, allowing grease to ingress into the pressurized nose fuselage underfloor area.

The O-ring was replaced and correctly installed; cap reinstalled per AMM and the aeroplane was made serviceable.

Transport Canada Comments:
Grease in that area is potentially dangerous because of the close proximity of four oxygen bottles therefore Bombardier Aerospace has issued advisory wire AW700-53-0328, defining this possible scenario and corrective action.

Transport Canada Civil Aviation would like to advise all BD700 operators of this event and of the advisory wire instructions issued by Bombardier. Hammer and wrench in X formation indicating end of article

Pinched at two locations allowing grease to pass

BOMBARDIER, CL600 2D15 (705)
SDR # 20101209005
Spoiler Power Control Unit Harness Clamp Chaffing

SDR submitted:

While carrying out a planned maintenance inspection task of the flap system, it was noticed that the flap drive torque-tube located directly under the right-wing inboard flight spoiler power control unit (PCU) was rubbing on a harness p-clamp when the flaps were transitioning from zero to eight degrees and back. The p-clamp was determined to be incorrectly installed and was repositioned 180 degrees in a pointing up position to provide the required clearance.

Transport Canada Comments:
There are 4 multi function spoiler PCU’s on the aeroplane. The Aircraft Maintenance Manual (AMM) outlines the procedure specifically for the installation of the 4 different PCU’s.

Presently in the AMM, there is no mention of the required p-clamp positioning that secures the wiring harnesses of the PCU’s.

Transport Canada Civil Aviation (TCCA) is presently working with Bombardier Aerospace to address this issue.

TCCA advises all operators of this possible PCU harness configuration discrepancy. Hammer and wrench in X formation indicating end of article

Correct clamp configuration | Relocated PCU harness p-clamp to provide required clearance

Incorrect clamp configuration | Torque-tube designed pivot motion during flap transition  | Incorrect PCU harness p-clamp position causing hard chaffing

SDR # 20091207005
Flap Transmission Support Bracket – Cracked/Dislodged

SDR submitted:

Uncommanded flap retraction from 20 degrees to 10 degrees during approach resulted in a drop of 50 feet. Shortly thereafter, the flap motor circuit breaker popped.

Following an uneventful landing; maintenance personnel found that the flap transmission support bracket had buckled and twisted, thereby pulling the flap transmission out of position.

Cessna Caravan Service Bulletin CAB05-4 (4 April 2005) titled “Flap Actuator Support Bracket Inspection/Replacement” had been complied with, on 28 August 2005, at TSN 6959 airframe hours. CAB instructions are to inspect for cracks along the inboard and outboard flange radius on the forward and aft areas of the support bracket. The operator then carried out Cessna Service Kit (SK) 208-158 to replace the support bracket.

Transport Canada Comments:
The flap transmission brackets absorb significant air loads when the flaps are deployed; therefore it is important that the crew ensures that flap limitations/airspeeds are followed in accordance with the Pilots Operating Handbook. A loss of lift during a critical phase of flight (approach) can greatly reduce the level of flight safety.

It is also recommended that maintenance personnel pay particular attention to the inspection of this flap bracket area. Hammer and wrench in X formation indicating end of article

SDR # 20071211001
Elevator Trim Actuator – Freeze Up

SDR submitted:

During cruise flight with autopilot engaged, the cockpit Advisory Message indicated “Mistrim Nose Dn”. The pilot disengaged the autopilot and then noted that additional forward control column force was required to maintain level flight. The pilot was unable to move the elevator trim forward because the trim wheel was jammed. The trim indicator also indicated a position forward of the take-off range. It was also determined that the elevator trim would move rearwards but not forward. Following an emergency declaration to ground control, the crew conducted a normal approach and uneventful landing.

Maintenance personnel carried out a functional check of the elevator trim system but were unable to duplicate the reported condition. Further examination revealed that the elevator trim screw jack assembly lubricant appeared to be milky in color with some water visibly present. Both the L/H and R/H screwjack assemblies were then purged of all contaminated grease/water and lubricated in accordance with the manufacturers’ instructions.

Prior to this flight, the aeroplane had been parked outside in heavy rain, which may have resulted in a buildup of water in the screw jack actuator cavity. By the time the aeroplane reached cruising altitude, ice had formed and restricted elevator trim movement. It appears that ice had clogged the trim actuator chain links preventing trim movement. Additionally, one of the tail plane access holes was not properly sealed thus permitting water to migrate into this aresa.

Transport Canada Comments:
A review of the SDR database revealed two similar reports related to water ingress and “freeze up” of the trim actuator chain link mechanism.

Operators are reminded to be cognizant of these hazards in inclement weather. Hammer and wrench in X formation indicating end of article

Trim Chain Grease seems to be milky in appearance suggesting it has had some moisture absorbed

SDR # 20110330007
Hydraulic Lines Swapped

SDR submitted:

After a series of flights and daily inspections, maintenance engineers noticed a slow transfer of hydraulic fluid between the left and right hydraulic systems. Detailed inspection of past maintenance activities was initiated in conjunction with recommendations from the manufacturer.

The left aileron servo actuator hydraulic system return lines were found to be interchanged. The left system pressure was returning to the right system hydraulic reservoir and vise-versa for the right system pressure.

The lines were returned to their correct positions and the aeroplane was released for service with a monitor for close hydraulic system reservoir level checks.

After several flights it was noted that the fluid transfer continued yet significantly reduced.

Further maintenance inspections discovered that the right aileron servo actuator system return lines had also been interchanged. The lines were reconfigured in their correct positions, the aeroplane was made serviceable and after several flights it was confirmed that the fluid transfer had stopped.

Transport Canada Comments:
Correct hydraulic line configurations are essential for proper aeroplane hydraulic system operations.

The Aircraft Maintenance Manual (AMM) chapter 27-10-80 contains a “note” specific to the above scenario defining the correct hydraulic line installation configuration.

In correlation with the Fault Isolation Manual (FIM), the AMM should also be used to confirm correct system operation and installation when trouble-shooting a snag. Hammer and wrench in X formation indicating end of article

SDR # 20101007014
Engine Mount Cracks

SDR submitted:

Upon a routine servicing, maintenance found the L/H lower engine mount tubular frame to be cracked through on both of the inboard and outboard areas. The engine mount was removed and sent for repair.

Transport Canada Comments:
A similar event occurred to the same operator on another aeroplane where Transport Canada Civil Aviation (TCCA) advised M7 Aerospace, the manufacturer and type certificate holder of the aeroplane, along with the Federal Aviation Authority (FAA).

TCCA would like to advise all operators that M7 Aerospace have recently issued Service Bulletin 226-71-018 for a detailed inspection of the concerned engine mount area. Hammer and wrench in X formation indicating end of article

Through cracks found and area of inspection of newly released Service Bulletin

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