The error message "Surveillance Equipment (ICAO): 'B1' is invalid" occurs when a transponder code is missing from the ICAO Surveillance Equipment field. To resolve this issue, include a valid transponder code (A, C, E, H, I, L, N, P, S, or X) along with the ADS-B code in the ICAO Surveillance field of the flight plan.
Commonly Used ICAO Transponder Codes:
- A: Mode A only (no altitude reporting)
- C: Mode A and C
- S: Mode S with Aircraft ID and Altitude
- E: Mode S with Extended Squitter (ADS-B Out, commonly used)
- L: Mode S with Extended Squitter and Enhanced Surveillance (EHS)
Common Configurations and Recommended Codes:
Transponder and ADS-B Out systems with the recommended ICAO Surveillance codes are listed in the table below:
| Device | Filing Codes |
|
Bendix/King |
|
|
KT 74 |
E, B1 |
|
KT76A |
C |
|
FreeFlight |
|
|
Ranger XVR with mode A/C transponder |
C, U2 |
|
Ranger Lite with mode A/C transponder |
C, U1 |
|
Garmin |
|
|
GTX327 |
C |
|
GTX330 |
S |
|
GTX 330ES |
E, B1 |
|
GTX 335 |
E, B1 |
|
GTX 335R |
E, B1 |
|
GTX 345 |
E, B2 |
|
GTX 345R |
E, B2 |
|
GDL 88/84 w Mode S transponder |
S, U2 |
|
GDL88/84 with Mode A/C transponder |
C, U2 |
|
Lynx |
|
|
Lynx NGT-9000 series |
E, B2 |
|
Stratus |
|
|
Stratus ESG - file |
E, B1 |
|
Trig |
|
|
TT31 |
E, B1 |
NOTE: Including only the ADS-B code (e.g., B1 or U1) without a transponder code will result in the flight plan being rejected. Always pair the ADS-B code with a valid transponder code for successful filing.
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