Fixed Wing

BOEING, 767 333
SDR # 20100629007
Under-floor wire bundle arcing

SDR submitted:

Sparks were noted emanating from an In-Flight Entertainment (IFE) wire bundle section below floor of a Boeing 767. This condition resulted in the tripping of circuit breaker TR-4. Further maintenance investigations found a wire arcing and shorting to a clamp due to its shielding being worn. The bundle was opened, repaired with a sealed splice per SWPM 20-30-12, then cleaned and inspected for further damage. Additional protection with tape per SWPM 20-10-13 was applied and a larger replacement clamp was used. The wire bundle was resecured; TRU #4 and Thales system checked serviceable per Thales AMM SUPP. 44-22-04.

Transport Canada Comments:
As aircraft technology advances and more electronic equipment is being used, such as this case with complex IFE systems, the essential requirement for diligence towards proper wiring practices is critical.

Always ensure harnesses are well supported through correct clamp sizes and proper shielding. Hammer and wrench in X formation indicating end of article

Under-floor wire bundle arcing 

SDR # 20081121009

Chafed Hydraulic Line on Challenger 300

SDR submitted:

While in cruise flight, the amber (R HYD Press Low) Crew Alert System (CAS) message illuminated. Pilot observed the hydraulic synoptic page and noted the fluid level in the right hydraulic reservoir was dropping. Aircraft (ACFT) began descent. During approach, pilot noted the right hydraulic reservoir quantity was reading (4%). After landing, visual inspection of the ACFT revealed hydraulic fluid streaming from the wheel well area to the tail of the ACFT.

Maintenance found a hydraulic line in the aft equipment bay that had a hole in it caused by chaffing on a fairlead block.

Transport Canada Comments:
This is the second SDR received in 30 days for chaffing hydraulic lines in the same area. Proper protection and clearance will prevent line chaffing and prevent in-flight safety occurences. Hammer and wrench in X formation indicating end of article


BOMBARDIER, BD 700 1A10 / 1A11
SDR # 20100629003

Variable Frequency Generator Rupture and Failure

SDR submitted:

In cruise after 8 hours of flight, the aeroplane had a Variable Frequency Generator (VFG) #1 fail. The crew heard a loud bang followed by a “Gen 1 Fail” message on the Engine Indicating and Crew Alerting System (EICAS). A visual inspection conducted after landing confirmed that the L/H engine lower cowling had been punctured and the VFG sump casing was extensively damaged. Additional damage to the VFG #1 oil and the engine driven pump (EDP) drain line was found.

Transport Canada Comments:
This has been the second occurrence of this type of VFG rupture and failure since the introduction of the Global Express Aircraft.

Failure investigation has revealed that under cold conditions in flight, where the VFG oil viscosity is high, the cooling oil flow is reduced which can lead to rotor diode failure. This investigation has been linked to a recent change in oil filter element material with low oil flow at low temperatures.

Bombardier Aerospace has issued Advisory Wire AW700-24-0313 rev 8 and will continue to investigate this occurrence. Hammer and wrench in X formation indicating end of article

Variable Frequency Generator Rupture and Failure 

BOMBARDIER, CL600 2B19 (RJ100)
SDR # 20090203007

Loose Bearings

SDR submitted:

While rigging the parking brake cable, small balls were found at the bottom of the compartment housing the brake control valve P/N 600-88101-125. Upon further investigation, it was discovered that the two follower bearings for the pilot brake pedal input to the brake control valve were destroyed.

The part cycles, TSN and TSO are unknown on the bearings. Hammer and wrench in X formation indicating end of article


BOMBARDIER, CL600 2B19 (RJ100/200/440)
SDR # 20100610002

Windshield Center Post Support Structure Crack

SDR submitted:

During a scheduled maintenance visit and completion of task RJ2-53-220-604, detailed inspection of a CRJ 100 windshield center post and bulkhead aft post at FS202.75, maintenance found the windshield center post lower forward strap cracked at FS210.00, CL0.00 and WL110. The post strap was repaired per drawing and Structural Repair Manual (SRM) and made serviceable.

Transport Canada Comments:
This aircraft had accumulated 32 300 hours of flight and 26 141 flight cycles when this crack was found during a 72 month inspection interval.

Transport Canada Civil Aviation would like to emphasize the importance for all maintainers to follow the required maintenance program that is defined by the manufacturer. Hammer and wrench in X formation indicating end of article

Windshield Center Post Support Structure Crack 

BOMBARDIER, CL600 2B19 (RJ100/200/440)
SDR # 20100329009

NLG Door Actuator Support Mechanism Cracks

SDR submitted:

During a routine inspection, maintenance found cracks on the base of the nose landing gear door (NLG) actuator support mechanism, located in the NLG bay.

The cracks were at both the forward and aft lug pivot points for the lower lever pin. A new NLG door mechanism was ordered, the mechanism was replaced, functional tests were carried-out and the aeroplane was made serviceable.

Transport Canada Comments:
Further inspections on other aircrafts of the same model were done with no findings.

Through the close scrutiny of the mechanic involved, a potential NLG gear door failure and possible operational interference was averted. Hammer and wrench in X formation indicating end of article

View looking into the NLG wheel well, right hand side 

CONVAIR 340 (580)
SDR # 20101018014

Elevator Hinge Fitting - Gouged

SDR submitted:

Upon removal of elevator panels to facilitate inspection; it was discovered that the R/H elevator hinge fitting was grooved/gouged on the top radius of the fitting. It was apparent that the gouging was caused by one of the panel screws that attach the R/H elevator end cap fairing was too long. When the elevator controls were moved, the screw would continue to wear a groove in the fitting. It was later determined that incorrect screws were installed (too long) in the upper elevator access panel.

The Convair parts catalogue calls for an AN509-10-R7 screw; the rest of the fleet will be inspected for similar condition and rectify as necessary.

Transport Canada Comments:
Over a period of time, the structural integrity of the elevator fitting could be degraded. As a result, it would be an ideal condition for stress corrosion and possible failure of the elevator fitting. Hammer and wrench in X formation indicating end of article

Interference damage from too long of a panel screw 

SDR # 20100701006

Rudder Push-rod Chaffing

SDR submitted:

During a scheduled maintenance inspection, the rudder push-pull non-adjustable rod was found chafing hard against an elevator servo hydraulic pressure line. The rod was replaced with serviceable unit and the lines repositioned.

Transport Canada Comments:
It is suspected that the elevator servo pressure line was improperly tightened in a manner that allowed it to twist and in-turn causing it to chafe on the rudder push-pull tube.

Transport Canada Civil Aviation recommends that when working in this area to pay close attention to this possible scenario and to always ensure not to pre-load hydraulic lines during installation. Hammer and wrench in X formation indicating end of article

Hydraulic-line b-nut twisting torque direction - Rudder control rod and chaffing point 

SDR # 20091204008

Cabin Overhead Connector - Overheated

SDR submitted:

During a major inspection, the L/H overhead light connector 3320-P40 and receptacle 3320-J35 were found severely burnt.

This event occurred on a foreign registered aircraft, thus it is not known how long the receptacle was in this condition.

Transport Canada Comments:
It is unknown what caused this extensive damage; however, connectors have been particularly vulnerable to condensation in the past, due to condensation within the shell. Special connectors with waterproof features have been developed for use in high humidity areas (e.g. cabin overhead ceiling areas). Hammer and wrench in X formation indicating end of article

 Cabin Overhead Connector - Overheated

SDR # 20100802002

Pre-cooler Seal Failure and Wiring Damage

SDR submitted:

While maintenance was performing a scheduled inspection task within the right engine pylon, wiring harnesses W606 and W607 including some adjoining clamps were found with heat damage from a hot air lead at the pre-cooler.

The wire harnesses were repaired as per the standard wiring practice manual (SWPM) and the pre-cooler gasket was replaced and the aeroplane was returned to service.

Transport Canada Comments:
The pylon harnesses that are being damaged by the pre-cooler engine bleed air leakage provide various engine control and monitoring functions.

Transport Canada Civil Aviation is presently working with Embraer Continuing Airworthiness to correct the pre-cooler bleed air leakage fault in-order to decrease the possibility of damaging pylon-wiring harnesses. Hammer and wrench in X formation indicating end of article

Pre-cooler bleed air leakage wiring damage - Engine bleed air entrance into pre-cooler 

SDR # 20100714004

Metroliner Cabin Window Retainer Crack

SDR submitted:

The aeroplane was undergoing a cabin inspection for window frame fastener corrosion when maintenance found a crack in R/H #4 window inner retainer. The crack measured 11.176 cm (4.4 inches) running between and parallel to the 2 rows of fasteners at the lower edge of the retained.

The window structure was repaired and the aeroplane was returned to service.

Transport Canada Comments:
This retainer is the only structure attaching the window assembly to the fuselage and if the crack was allowed to continue to propagate, it could have resulted in a rapid depressurization and possible loss of the window assembly.

Recently at the last revision, maintenance inspection tasks were added in the Maintenance Planning Manual (MPM) to detect this type of failure.

Transport Canada Civil Aviation would like to ensure that all owners and operators are aware of this possible scenario and of the new maintenance inspection
tasks available.
 Hammer and wrench in X formation indicating end of article

Metroliner Cabin Window Retainer Crack of 4,4 inches

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