Investigation support for TSS-4100 Failure in-flight
Effectivity: Challenger 300/350/650, Global 5000 Vision/6000/6500/5500/7500/8000 aircraft
ATA: 34-43/34-54 Navigation TCAS /Transponder
By: Camelia Constantin – Avionics, Technical Services, Challenger/Global Series In the past 12 months, the Aircraft Health Management System (AHMS) has shown an increase in TSS-4100 system failures in-flight. The investigation of the Traffic Avoidance Collision System (TCAS) transponder #1 intermittent failure with the associated XPDR 1 FAIL CAS and/or on Global TCAS FAIL CAS message or on Challenger TCAS FAIL on the primary flight display, indicates that TSS-4100 could potentially be affected by the following conditions (Ref. AW000-34-0038):
Continuous Wave (CW) interference
Applicable: TSS-4100 P/N: 822-2132-001/-002
FDE: TCAS/Transponder #1 fault clears only after a power cycle and occurs frequently in a specific geographic location.
NSEU (Neutron Single Event Upset)
Applicable: TSS-4100 P/N: 822-2132-001/-002/-003
FDE: TCAS/Transponder #1 fault clears by itself within 30 seconds.
Extended Squitter Fault
Applicable: TSS-4100 P/N: 822-2132-003
FDE: TCAS/Transponder #1 fault typically clears by itself within few minutes.
It is important to understand that there are many other possible faults that can cause a momentary loss of Transponder and TCAS functions. It should not be assumed that all TCAS/Transponder #1 indications are caused by the above.
To further investigate the TSS-4100 failure in flight and improve unit reliability, Bombardier asks aircraft owners and operators to report any of the above conditions, as follows:
Continuous Wave (CW) interference
If CW Interference is suspected at a particular location, it is recommended to notify the appropriate regulatory agency, e.g. Federal Aviation Administration (FAA) or, you can report the condition to your local Bombardier Field Service Representative (FSR) or the Customer Response Centre (CRC), so a case is open in the Bombardier system. Please include the following information in the report:
Aircraft model and serial number
Date of the event and time
Phase of flight (i.e. climb, cruise, descent) when the fault occurred
Approximate location
Approximate altitude
Specific failure annunciation
Information on how the fault was cleared
For the FAA, the following link can be used to identify the appropriate Flight Standards District Office (FSDO): https://www.faa.gov/about/office_org/field_offices/fsdo
NSEU (Neutron Single Event Upset) & Extended Squitter Fault
These two events share similar FDE behavior, which makes them difficult to differentiate. Therefore, we highly encourage the customer to follow the same reporting process. If NSEU or Extended Squitter Failure is suspected at a particular location, it is recommended to report the condition to your local Bombardier Field Service Representative (FSR) or the Customer Response Centre (CRC) so a case is open in the Bombardier system. Please include the following information in the report:
Aircraft model and serial number
Date of the event and time
Duration of the event
Phase of flight (i.e. climb, cruise, descent) when the fault occurred
Approximate location
Approximate altitude
Specific failure annunciation
Information on how the fault was cleared
TSS-4100 P/N and S/N
Furthermore, if any of the above failures are suspected, Collins Aerospace does not recommend removing units from the aircraft, as replacing the unit will have no impact on this condition.
Operators will be kept updated on the investigation status via a revision of AW000-34-0038 as new information is made available.
Thank you for your support.