Weather detection on Honeywell RDR-7000 system
Effectivity: Global Express/XRS/5000 aircraft equipped with Honeywell weather radar’s ART-7000 Transmitter-Receiver Unit (Supplemental Type Certificate T00003NY)
ATA: 34-41
By: Salah ud Din — Technical Services Bombardier would like to inform operators equipped with Honeywell RDR 7000 weather radar systems about a weather detection issue outlined in Honeywell SIL D202402004286.
Operators have reported instances of missing weather radar data on their navigation displays, particularly at ranges between approximately 50 and 120 nautical miles (nm) ahead of the aircraft.
During radar return processing, the ART-7000 distinguishes between returns from weather targets and ground terrain targets based on an internal terrain database. Upon investigation, it has been discovered that misclassification occasionally occurs where weather returns are incorrectly placed in the memory partition designated for ground terrain returns instead of the intended weather returns partition. This misclassification mainly affects radar returns from low-altitude rainfall at altitudes of 5,000 ft (1,524 m) or lower. Correct classification typically occurs when the misclassified returns approach within 50 nm ahead of the aircraft.
To address this issue, Honeywell has devised the following plan:
Short-term Mitigation: Temporarily adjusting the radar's gain control to the manual gain function and setting the variable gain to maximum will display more weather-related returns in the 50 to 120 nm range. After evaluating the weather conditions, restore the radar's manual gain control to the calibrated or automatic setting.
Long-term Solution: Honeywell will address this issue by releasing a new version of the application software for the ART-7000, known as TSO 2.0. The software update, expected to be available by the end of Q2 2024, is expected to significantly improve weather detection capabilities.
For additional details, figures and examples, please refer to the SIL posted on the Bombardier Customer Portal.