Reliability enhancement for Collins weather radars

Effectivity: Global and Challenger series aircraft equipped with Collins Aerospace weather radars (RTA 4218 & 41XX) 

ATA: 34-41 

By: Salah ud Din — Technical Services 

Bombardier would like to notify operators whose aircraft are equipped with Collins Aerospace weather radars RTA 4218, 4118, and 4114 about recent reliability improvements. 

Bombardier previously released service bulletins (SBs) that highlighted modifications to the weather radar system. These modifications (via Collins Aerospace SB RTA 41XX-34-8, Digital Signal Processor (DSP) Communication (COM) Fault Reliability Improvement) are meant to improve reliability. 

In an ongoing commitment to enhance weather radar reliability, Collins Aerospace released SB RTA-4218-34-3 (CPN 523-0834247) and RTA-41XX-34-9 (CPN 523-0834248) for RTA-4218 and RTA-4114 & 4118, respectively. Further details on these SBs are accessible on the Bombardier Customer Portal. The modifications aim to reduce WXR faults and mitigate noisy or banging antennas. 

In summary, modifications entail: 

(a) Replacement of boresight sensor threshold resistors on the power supply circuit card assembly (CCA). This replacement enhances the position signal and minimizes positional errors in motor movement. 

(b) Replacement of tilt and scan sensor vanes with improved vanes to eliminate any potential play that may occur in motor movement. 

(c) Replacement of the main interconnect cable mounting bracket to securely hold the cable in place against vibration and movement. 

(d) If inadequate post-coating is identified, perform touch-up/recoating is necessary. Humidity can alter critical values of electronic components, leading to errors. This measure ensures solder joints are shielded from humidity. 

Since June 2023, installation of these bulletins has been conducted by Collins Aerospace on all radars within their rental exchange pool.  

In addition, since that time, radar being updated via Bombardier recommended SB service also benefit from these latest improvements. 

For reference, here is the list of related Bombardier SBs, if they have not yet been performed on your aircraft:  

700-34-5029 / 700-34-5510 / 700-34-6029 / 700-34-6510 

605-34-037/ 650-34-020  

100-34-48/ 350-34-026