Attention:
Operators of MHI RJ AVIATION ULC. (MHIRJ) (Formerly Bombardier) CRJ100/200/440/Challenger 850 and CRJ550/700/701/702/705/900/1000 Aircraft Models
| File Classification No.: | Z 5000-35 |
|---|---|
| RDIMS No.: | 20497952 |
| Document No.: | CASA 2024-11 |
| Issue No.: | 01 |
| Effective Date: | 2024-11-15 |
Purpose:
The purpose of this Civil Aviation Safety Alert (CASA) is to raise awareness of an issue when an aircraft fails to complete a planned turn while on autopilot to capture the localizer and overshoots the localizer centerline.
Background:
On 8 May 2023, NAV Canada advised MHIRJ of a significant number of localizer capture issues on parallel runways in Toronto with CRJ900 aircraft.
While attempting to capture the localizer with the autopilot engaged, it has been noted that some aircraft overshoot the localizer centerline. Some of these aircraft have been able to successfully re-join the localizer, however others required vectors for another approach or had to execute a missed approach due to stabilization issues. This is not an issue specific to Toronto and is a known issue on all CRJ models. Past investigations have been unable to determine a root cause.
This issue is more likely to occur at long runways where the localizer beam is narrower, in developed (urban) areas and especially for more recent or updated localizer antennas with more elements.
Recommended Action:
This issue has been known since 2006. It may be occurring more frequently as the number of elements of newer localizers have increased to improve precision and the linear sector of the beam may become narrower. There have been presentations made to operators at Flight Operations Steering Committee (FOSC) meetings.
Flight crews should be familiar with the existing mitigating factors which are as follows:
- Procedures in Flight Operations Notes (FON):
CRJ100/200/440/Challenger 850-FON-34-014, CRJ700/705/900/1000-FON-34-027 “Localizer “False Capture” and Tracking Issues - Awareness and Mitigation Mode - Data Survey” was published in May of 2024 to raise awareness and recommend procedures to mitigate the risk. This FON supersedes previous FONs:
- CRJ700/705/900-FON-22-001
- CRJ100/200/440-FON-22-001
- CRJ100/200/440/Challenger 850-FON-34-006A
- CRJ700/705/900/1000-FON-34-010A
- Flight Crew Operating Manual (FCOM):
FCOM volume 2 chapter 4 – Normal Procedures – prior to landing – 4. The precision Instrument Landing System (ILS) approach includes caution to flight crew to avoid arming Approach (APPR) mode until the airplane is close to or established on an inbound localizer course.
- Other existing mitigations:
- a) The use of Traffic Collision Avoidance Systems (TCAS) provides an additional element of safety to parallel approach operations.
- b) Pilots are informed by the approach chart that simultaneous approaches to parallel runways are available and by Air Traffic Control (ATC) or through the air traffic information system when a class of simultaneous approaches is in use.
- c) These simultaneous parallel approach operations demand heightened pilot situational awareness.
- For simultaneous dependent approaches ATC radar monitoring ensures adequate diagonal spacing (lateral/vertical) during the turn onto and on final approach,
- Simultaneous independent approaches also require Non-Transgression Zone (NTZ) radar monitoring,
- Simultaneous close parallel Precision Runway Monitor (PRM) approaches require NTZ radar monitoring by two monitor controllers and specific pilot training.
Additional Actions:
MHIRJ is in process to revise and issue updates to the FCOMs to implement operational procedures based on changes introduced in the new FONs. The target date for release of the FCOM updates is in the first half of 2025.
Contact Office:
For more information concerning this issue, contact a Transport Canada Centre; or contact Daniel Haughton, Continuing Airworthiness in Ottawa, by telephone at 1-888-663-3639, by fax at 613-996-9178 or by e-mail at TC.CAWWEBFEEDBACK-retroactionWebMDLN.TC@tc.gc.ca.
Original Signed By
Jenny Young
Chief, Continuing Airworthiness
National Aircraft Certification
Localizer Tracking Anomaly
(PDF, 268 KB)
The Transport Canada Civil Aviation Safety Alert (CASA) is used to convey important safety information and contains recommended action items. The CASA strives to assist the aviation industry's efforts to provide a service with the highest possible degree of safety. The information contained herein is often critical and must be conveyed to the appropriate office in a timely manner. The CASA may be changed or amended should new information become available.