Feedback - Canadian Aviation Service Difficulty Reports
From Transport Canada
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Nose Landing Gear Damaged on Push-Back
During the aircraft push-back from the gate the tow bar shear pin sheared and the aircraft moved approximately 1 to 2 feet from its original position. The flight crew later reported the aircraft brakes were not released prior to initiating the push-back. Following the shear pin event, the tow bar was examined, the axle interface pins were bent and the tow bar head "yoke" was bent. Due to the over load caused by this event, the nose landing gear assembly and drag brace were replaced. The right nose wheel assembly was also replaced due to the damaged rim caused by the tow bar.
Transport Canada Comments:
This report serves as a reminder that these types of incidents can and do occur, even to highly trained and professional personnel.
It is easy to fall into the trap of examining only the events immediately leading to such an incident. Asking whether or not there was communication between the flight deck and ground crew prior to the aircraft being pushed back is natural and important, but there is also a lot of value in examining the organizational and human factors that likely contributed. Were there time pressures? Was fatigue a factor? Was this a routine push-back, or was something different? Etc.
A properly implemented Safety Management System (SMS) can help an organization learn from and avoid such incidents by helping them identify organizational and human factors during the investigation process. An SMS can also help identify hazards that are inherent, but not always obvious, in day to day operations. With that type of knowledge organizations can build policies and procedures to defend against these types of incidents and work to strengthen their own internal safety culture.
Improvements to the online submission of the Annual Airworthiness Information Report (AAIR)
On August 2nd, 2018, Transport Canada (TC) launched the newly redesigned Continuing Airworthiness Web Information System (CAWIS) which included enhancements to the online submission of the AAIR. Some of the improvements include:
There is now a specific AAIR login page for aircraft owners. The login page will require a User ID and Password instead of an AAIR access code. User IDs will be assigned by TC and will remain the same each year.
For aircraft owners who had an AAIR access code, the User ID is the first part of that access code. For example if your access code was 123456 ABCDE, your Used ID will be 123456.
Owners are now able to create their own unique AAIR password via the AAIR login page and also recover a forgotten AAIR User ID.
The webpage layout has been redesigned in order to facilitate the data entry of the AAIR information. The functionality of certain areas, for example the AMO/AME section, has been updated in order to provide a more user friendly experience.
The most recently reported Hours flown since new and inspection date are now shown to facilitate entering in information previously reported which is remaining unchanged.
Print AAIR anytime
Owners are now able to log into CAWIS anytime during the year in order to print their most recently submitted report.
We hope our continued improvements to the CAWIS system make submitting the AAIR easier to complete. If you have any questions related to the AAIR program, please contact our office at 1-888-663-3639 (Option 1) or by email at firstname.lastname@example.org.
You will find below, email addresses to be used for various situations. To be sure you receive all pertinent information from the National Aircraft Certification branch, we recommend you save these addresses in your contact list and make appropriate adjustments to your SPAM protection.
- TC.DoNotReplyNAC-NepasrepondreCNA.TC@tc.gc.ca: This address is used to distribute safety publications/messages. This mailbox cannot accept incoming emails.
- email@example.com: This address is for all questions/concerns related to the Annual Airworthiness Information Report (AAIR) program.
- AD-CN@tc.gc.ca: This address is for all questions/concerns related to Airworthiness Directives.
- TC.NACcommunications-CommunicationsCNA.TC@tc.gc.ca: This address is for all distribution questions/concerns including updating your email address.
- SDRS@tc.gc.ca: This address is for all questions/concerns related to the Service Difficulty Report (SDR) program including technical support with the online WSDRS system.
- firstname.lastname@example.org: This address is for all other Continuing Airworthiness matters including CASAs and Feedback articles.
Bombardier, CL600 2D15 (705), CL600 2C10 (700, 701, 7020 and CL600 2D24 (900)
Frame corrosion under forward passenger door
SDR #: 20170817016
While investigating an unrelated defect, corrosion was found in the area under the floor near the passenger door. Maintenance staff removed and replaced the intercostal from frame fuselage station (FS) 310 to 333.00 and from stringer (STR) 25L to 26L as per Structural Repair Manual (SRM) 51-00-00 and Bombardier Aerospace drawing number SH670-31810. Additional corrosion was discovered on the foot of the frame at FS 319.70 between STR 20L to 21L. This frame was also removed and replaced with a new frame as per SRM 51-00-00 and Bombardier Aerospace drawing number SH670-31810. Please see the attached pictures to view the damaged pieces and severity of the corrosion.
Transport Canada Comments:
While the submitter does not specify a cause, it is likely that the corrosion was the result of water and moisture that passed through the floor and accumulated in the bilge area. This location is susceptible to water ingress because it is a high traffic area and is often subjected to the outside elements such as rain and snow. When the stairs are raised, any water or melting snow will also drip onto the floor and may then pass through the floor seals. On many models of this aircraft a galley is also located nearby, providing opportunity for spilled liquids.
After discovering this corrosion, the operator chose to update its company’s corrosion protection and control program, to better address this issue.
Engines and APU’s
Oil Servicing Safety Issues
SDR #: Not applicable
Oil servicing issues continue to occur in the aviation industry, including over and under servicing engines, failing to properly secure oil filler caps and failing to latch access doors/panels. These events can lead to loss of oil and engine shutdown, smoke or odors in the cabin and loss of panels in flight.
Human factors studies tell us that the reason for these events can include complacency, fatigue, distraction, a lack of experience, inadequate training, etc. A properly implemented Safety Management Systems (SMS) can help reduce occurrence rates.
When Transport Canada receives reports of these (and other) types of occurrences, the information is passed on to the type certificate holder (TCH) of the affected product. Transport Canada Continuing Airworthiness works with the TCH towards reducing both the rate of occurrence and the impact.
Some of the resulting corrective actions may include: design changes (such as check valve installation on oil filler necks), awareness campaigns through various publications and revised labeling and placarding.
Maintainers must remember that although oil servicing is a routine task, it is absolutely vital to flight safety. Servicing tasks (however routine they may seem) need to be carried out correctly and completely, in accordance with the latest manufacturer’s instructions. It is worth noting that manufacturers’ websites are excellent resources for safety information regarding the operation and maintenance of their products.
V-Band Couplings and Clamps
Maintenance of V-Band Couplings and Clamps
SDR #: 20170404021
Best Practices for Maintaining V-Band Couplings / Clamps
Transport Canada Comments:
V-band couplings and clamps can be found on many general aviation and commercial aircraft. These units are frequently used to attach exhaust and turbocharger assemblies. This important, yet often overlooked item, plays a critical role in the function and safe operation of the aircraft. Failure of these items has led to serious in flight emergencies including engine power loss, engine failure and in flight fire. The difficulty with these items is that due to the nature of the installations, they are often extremely hard to inspect. Some of the issues that can arise from normal operation (due to the harsh operating environment) can include cracking, loosening of fasteners and weld breaks. It has been reported to Transport Canada that some of these units from PMA (Parts Manufacturing Approval) manufacturers have failed even when new (as seen in the photo below –spot welds not holding together).
Recently the Federal Aviation Administration (FAA), in conjunction with an industry working group, released a ‘best practices guide’ regarding V-band couplings / clamps. This article contains a great deal of valuable information regarding the installation, inspection and maintenance of these units. Transport Canada recommends that operators and maintainers of aircraft equipped with these couplings review this article. The following is the link to the FAA best practice guide:
Teledyne Continental Motors Ignition Switches
SDR #: 20170623010
Note: TCCA has made minor editorial changes and additions to the original text of the SDR, for improved reading and better logic flow.
The aircraft was snagged for “engine won`t start”. Troubleshooting was carried out and maintenance found the ignition switch to be faulty. The switch was checked in accordance with Diamond DA20-C1 aircraft maintenance manual (AMM) chapter 74-00-00, p 201- ignition switch test #2, item number 3 on page 202. When tested in the “start” position, the left retard was found to be “open” which was correct, but it was also found that the left and right advance cable points were “open”. These contact points should have read zero ohms or “closed”. A new switch was obtained from the company’s primary base of operation. It was tested in accordance with the AMM, found serviceable and installed.
The defective switch had been replaced for troubleshooting purposes due to an “erratic starter engagement” the previous week. The switch was not checked for correct continuity at that time of installation and had accumulated 21.1 hours in service.
During the current snag troubleshooting, when the switch was found to be defective, there were no new switches in stock at the company’s sub base, so a serviceable switch was removed from an aircraft down for a 1500 hour inspection. When that switch was tested prior to the planned installation to rectify the snag, the then removed serviceable switch was found to have the same defect as the switch with the 21.1 hours in service. The total time in service of the removed serviceable switch is unknown at this time and there is no record of replacement within the previous 6 months. The removed serviceable switch was red tagged and placed in quarantine stores.
Transport Canada Comments:
The original equipment switch part number (P/N) listed in the DA20-C1 Illustrated Parts Catalog (IPC) is shown as being P/N A-510-2. The latter is manufactured by ACS Products Company. In this particular SDR, the faulty ignition switch is identified as being P/N 10-357210-1. This ignition switch was previously manufactured by Bendix Engine Components Division (Bendix), now part of Teledyne Continental Motors (TCM). The DA20-C1 IPC specifies that the Bendix P/N 10-357210-1 ignition switch is an optional switch with a “push-to-start feature”. It is eligible to be installed on the DA20-C1 by virtue of Diamond Service Bulletin (SB) DAC1-74-03, now at revision 2.
This SDR raises a potential airworthiness concern with respect to the possibility of a latent or hidden failure of the ignition switch. In this particular case, the switch failed to an open or no-start condition. TCCA searched the WSDRS database and found 6 SDRs between 1984 and 2010 related to the original ACS Products Co. P/N A-510-2 switch and 25 SDRs between 1975 and 2017 related to Bendix P/N 10-357210-1 switch. The problem descriptions of the SDRs reveal several potential failure types, including failed open / “no-start” failures, intermittently failed open / “erratic starter engagement” failures and failed closed / “hot start” failures. The latter are particularly problematic because such failures could result in an un-commanded start with potential death or serious injury to ground personnel due to unexpected propeller rotation.
The Federal Aviation Administration (FAA) issued Airworthiness Directive (AD) 76-07-12 on April 14 1976, against several Bendix part number ignition switches, including the P/N 10-357210-1 switch. The AD was subsequently amended effective August 30 1977. The AD requires an operational check of the ignition switch every 100 hours, by running the engine and rotating the ignition switch to the extreme “off” direction. If the engine keeps firing, it indicates a malfunctioning switch. The AD refers to Part III of Bendix SB No. 583, issued in April of 1976, for repair and replacement of the switch. In addition TCM issued SB 660 which addresses testing the Bendix switches every 100 hours or annual inspection.
The FAA also issued the very similar AD 93-05-06 against ACS Products Co. and Gerdes Products Co. ignition switches, including the ACS P/N A-510 series of switches. The AD is effective April 29 1993, and requires an inspection of the switch to detect wear and corrosion and to further disassemble and lubricate the switch, all in accordance with ACS SB 92-01, dated August 15 1992, or Cessna SB SE91-5, revision 1, dated June 14 1991. The AD requires a repeat inspection and lubrication of the switch every 2000 flight hours. It also requires a one-time inspection at the first 100 hours or next annual inspection to determine if a diode or surge suppressor is installed on the starter solenoid and, if not, to install one. Failure to install a diode or suppressor could accelerate damage to the switch contacts.
The DA20-C1 AMM incorporates ignition switch resistance and continuity testing requirements with an ohm meter in Chapter 74-00-00, every time the switch is replaced. It should be noted however that the specific types of ignition switches described in this article are not limited to the DA20-C1 aircraft model. They are commonly used on multiple aircraft models in the general aviation segment, including Diamond, Cessna, Piper, Schweizer, Grob-Woerke, American General, and Burkhart Grob. The underlying safety issue may potentially affect thousands of aircraft.
TCCA reminds general aviation aircraft owners, operators and maintainers of the potential for latent failures and the inherent safety risks of these types of ignition switches and to take the appropriate corresponding safety actions required by the relevant ADs and SBs.
ATR 42 - Wheel Assembly Tie Bolt Failures
It has come to the attention of Transport Canada through the Web Service Difficulty Reporting System (WSDRS) that numerous operators of the ATR-42 series aircraft, have had main wheel tie bolts found sheared or missing.
Over the past year, nine SDRs have been submitted via the WSDRS for this problem.
Typically, the operators have reported hearing an odd sound emanating from the wheel assembly while towing the aircraft in the hangar or from the gate. Upon further inspection, most operators find the remains of a tie bolt loose within the cavity between the brake system and the wheel. Other operators have detected the problem upon removal of the wheel assembly, due to tire wear or one operator found the wheel assembly would not hold air pressure.
The manufacturer of the wheel assemblies, Meggitt Aircraft Braking Systems, issued service bulletin (SB) ATR42-32-33, dated June 14 1999, to attempt to address this issue. Meggitt has introduced through this SB an increased torque value and torqueing sequence for the tie bolts, as well as specific cautions as to the use of power and automatic tightening devices.
Most operators send their wheel assemblies out to overhaul facilities for repair and non-destructive testing (NDT) as applicable. It is recommended that the operator ensure the overhaul facility is following the most up-to-date information prior to performing the overhaul and assembly of these wheel assemblies. Special attention should be given to the tie bolts themselves. The Meggitt component maintenance manual (CMM) for the wheel assemblies in the part number 5006856 series has specific instructions pertaining to the inspection of the bolts and nuts, including a Magnetic-Particle Inspection (MPI) for cracks, paying particular attention to the radius under the bolt head and to the threads adjacent to the bolt shank.
The CMM also states “An equivalent bolt maintenance program may be established by aircraft operators with service experience whereby bolts are replaced based on usage.”
Transport Canada recommends following the CMM and SB ATR42-32-33 while operating these wheel assemblies. Doing this should give operators of the ATR-42 series aircraft the life expected from these components.
757-2B7 - The Effects of Skydrol
SDR #: 20171004006
While approaching the gate, the crew noticed a "left hyd. Qty." warning message appear. The aircraft was brought to a stop at the gate, and shut down normally. Maintenance noticed a large hydraulic leak from the left gear bay, and a total of 5 ramp personnel assisting with marshaling the aircraft were exposed to the atomized skydrol as a result of the high pressure leak. The ramp personnel affected were taken to the hospital with various symptoms, including vomiting. Maintenance staff found the cause of the leak, which turned out to be a ruptured hydraulic line going to the down lock actuator, and subsequently replaced the unserviceable component.
Transport Canada Comments:
This SDR reminds us of the effects of Skydrol on the body. These individuals were not expecting to be in contact with the chemical. When you are anticipating the potential of contact with Skydrol, please wear proper personal protective equipment (PPE) such as gloves and eye protection.
BOMBARDIER, CL-600-2D15 (705)
Equipment Airworthiness Directive on Crew O2 Mask
The oxygen mask was received for servicing and the defect noted was "observer mask has a hole in it". Upon inspection and teardown, it was found that the harness assembly was 12 years old and blown. The manufacturer recommends to replace the inflatable harness assembly every 6 years. Upon further inspection, a number of other discrepancies and evidence of improper/substandard maintenance were noted.
The main concern/problem is a blown inflatable harness with over 12 years of service indicates a lack of proper inspection and recommended maintenance. There were no inspection letter markings found on the harness indicating that Zodiac service bulletin (SB) MXH-35-241 was carried out. This SB was required by EASA airworthiness directive (AD) 2011-0090R1 and dates back to June 23, 2011 with accomplishment instructions within 24 months.
The mask assembly was manufactured in November 2001, and the combined diaphragm was dated 2004 which indicates no proper maintenance or overhaul had been done since new. It was also noted that the main casing which was dated October 2009 was replaced during a repair accomplished in 2010, however the combined diaphragm dated 2004 was put back into the regulator.
Service information letter (SIL) 18 recommends replacement of the harness every 6 years, and overhaul every 6 years.
Transport Canada Comments:
The submitter raises some good points and references the recommended intervals recommend by the manufacturer and the SIL. The question about the operator’s compliance with the EASA equipment AD 2011-0090R1 is certainly a concern. This equipment AD is effective in Canada and is in the Continuing Airworthiness Information System (CAWIS) database.
The manufacturer’s and the SIL recommendations are not necessarily a mandatory overhaul requirement. These items are manufacturer’s recommendations and used to make and amend an operator’s maintenance schedule approval (MSA). The MSA requirements and intervals may be the same or different depending on the actual Transport Canada MSA approval for the operator.
Without knowing the history of this line replaceable component and the installation and removal data, it is difficult to assess the missed AD compliance issue. Operators must be diligent in monitoring all applicable equipment ADs to remain in compliance with Canadian Aviation Regulation (CAR) 605.84 requirements, because they can come from many civil aviation authorities.
Transport Canada is publishing this article to raise awareness in regards to equipment maintenance and equipment ADs.
BOMBARDIER, CL600-2D24 (RJ900)
Circuit Breaker Panel Burned Through
The left hand cockpit main circuit breaker panel was burned through when a foreign metal object contacted the windshield wiper circuit breaker and grounded to the panel door skin. The ensuing electrical arcing burned through the panel creating a hole.
Transport Canada Comments:
The burnt part of the panel is actually a door which hinges down in order to provide access to the circuit breakers for maintenance and inspections. It is likely that during some previous maintenance event that the foreign object was dropped or left inside the panel. The object then moved and shorted out the wiper circuit breaker causing the damage to the panel door.
Service Difficulty Reports about fixed wing that either show a trend or should be known by the airworthiness community.
These are the most recent articles. The full list of articles can be found on the Fixed Wing page.
Service Difficulty Reports about engines that either show a trend or should be known by the airworthiness community.
These are the most recent articles. The full list of articles can be found on the Engines page.
Service Difficulty Reports about rotorcraft that either show a trend or should be known by the airworthiness community.
These are the most recent articles. The full list of articles can be found on the Rotorcraft page.
Suspected Unapproved Parts (SUP)
In Canada, SUPs are reported in accordance with section 571.13 of the standard of the Canadian Aviation Regulation (CAR).
When you suspect an unapproved part, the SUP report can be submitted on the SDR form or through the Web Service Difficulty Reporting System.
FAA Unapproved Parts Notifications (UPN)
Unapproved Parts Notifications are published by: FAA, AIR-140, P.O. Box 26460, Oklahoma City, OK 73125.
FAA Special Airworthiness Information Bulletins (SAIB)
A Federal Aviation Administration (FAA) SAIB is an information tool that alerts, educates, and makes recommendations to the general aviation community. It is non-regulatory information and guidance that does not meet the criteria for an Airworthiness Directive (AD).
EASA Safety Information Bulletin (SIB)
European Aviation Safety Agency (EASA) SIB is an information tool that alerts, educates, and makes recommendations to the general aviation community. It is non-regulatory information and guidance that does not meet the criteria for an Airworthiness Directive (AD).
Equipment Airworthiness Directives (AD)
Transport Canada (TC) endeavours to send copies of new Airworthiness Directives (ADs), which are applicable in Canada to the registered owners of the affected products. Equipment/appliance ADs are often only distributed to our regional offices because the owners of aircraft affected by this type of AD are not generally known.
Aircraft Maintenance Engineers (AMEs) and operators of the affected products are encouraged to obtain further information or a copy of the ADs from their regional TC office, their local Transport Canada Centre (TCC), their Principal Maintenance Inspector (PMI), or from the Civil Aviation AD website
Service Difficulty Reports (SDR)
Service Difficulty Reports are submitted by Aircraft Maintenance Engineers (AMEs), owners, operators and other sources to report problems, defects or occurrences that affect aircraft airworthiness in Canada.
Civil Aviation Internet Sites
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Reprints of original Feedback material are encouraged, but credit must be given to Transport Canada's Feedback. Please forward one copy of the reprinted article to the Editor.
To obtain information concerning copyright ownership and restrictions on reproduction of the material, please address your correspondence to:
Jérémie Laviolette, Editor
Transport Canada (AARDG)
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Tel.: 888-663-3639 Fax: 613-996-9178
The articles contained in Feedback are derived from Service Difficulty Reports (SDRs) submitted by Aircraft Maintenance Engineers (AMEs), owners, operators and other sources in accordance with Canadian Aviation Regulation (CAR) 521.
SDRs are normally published verbatim. Transport Canada assumes no responsibility for the accuracy or content of any of these reports. Only spelling errors are corrected and content may be reduced as well as personal references deleted.
All defects or occurrences should be reported to Transport Canada through the Service Difficulty Reporting Program. For additional information about this program or concerning an article in Feedback, contact your nearest Transport Canada Centre.
For all technical inquires related to articles of this magazine, please address your correspondence to CAWWebFeedback@tc.gc.ca
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ISSN 1925-8429 (Online)