Which aircraft models are associated with the B737-900?

• A. 37k and 73C
• B. 37k and 73G
• C. 73C and 73G
• D. 37k and 73H

Answer: (A)

In this material, you’re learning how a B737-900 is referenced alongside other 737 models for cross-reference in training and manuals. The B737-900 is linked with designators that represent the closest related 737 family members used in United’s documentation: 37K and 73C. The 37K code corresponds to the 737-700 family, and the 73C code covers the Classic 737 lineup (737-300/400/500). These pairings are used because they reflect which other models share similar systems, cockpit layouts, and maintenance references, making cross-training and equipment reference practical. Other pairings don’t align with United’s documented associations for the 737-900, so they aren’t the correct cross-reference.