In a series of brake certification tests conducted in Oklahoma, Boeing’s 777X test team faced severe weather conditions, including fierce winds, torrential hail, and thunderstorms.
Despite these obstacles, the team successfully completed the tests over 63 days, more than double the original forecast, and returned home in May, the manufacturing giant said.
The primary objective of these tests was to subject the aircraft’s brakes and wheels to hard-braking scenarios to demonstrate performance for certification credit. This process involved the use of 117 new wheels.
“We test these extremes so that we know where the boundaries are for the airplane, and we make sure that the airplane meets our expectations and the expectations of the regulator,” said Heather Ross, the jet’s project pilot, in a Boeing blog post.
![Boeing workers position fans to cool the 777X's wheels and brakes after testing. [Credit: Boeing/Paul Weatherman]](https://flyingmag1.b-cdn.net/wp-content/uploads/sites/2/2025/09/08e3dc84-ea92-457d-98af-26cb203ceac0.webp?width=1024&height=682)
Testing Continues
The 777X is equipped with a six-wheel main landing gear truck, similar to previous generation 777 variants. The tires used in these systems are built to withstand the immense forces encountered during landing and braking.
Typically, aircraft tires are inflated to about 200 psi, significantly higher than car tires, to handle the substantial loads and speeds.
The testing process required specific weather conditions, including calm winds (below 10 knots) and dry runways. However, due to unpredictable weather, the team often had to adjust its plans, sometimes relocating to different locations to continue testing.
Looking ahead, the 777X program plans to continue testing, including simulating ice formations on the aircraft’s wings and evaluating braking performance on wet runways. The program has faced a slew of delays.
Previously, Boeing expected to deliver the first 777X in 2020, but this plan has now shifted to 2026.
