Honeywell Mechanical Systems Deliver for 737 Airlines

Continuous improvement is the name of the game for engineering teams at Honeywell, which are always looking for ways to improve the effectiveness and reliability of our broad and diverse line of mechanical products.

Honeywell mechanical systems control the environment in the cockpit and cabin of commercial aircraft. They also improve engine performance, provide onboard electric power and perform dozens of other tasks critical to aircraft safety, efficiency and availability.

Honeywell Innovation Improves Fuel Tank Safety

For example, Honeywell has developed an air separation module (ASM) kit to enable Boeing 737 operators to upgrade the performance, extend the service life and reduce maintenance costs for this critical fuel tank safety system found on every commercial airliner. The ASM is part of the aircraft’s nitrogen generation system, which has all-but eliminated fuel tank explosions in recent decades.

The ASM separates oxygen from the aircraft engine’s bleed air to produce nitrogen-enriched air, which is then introduced to the fuel tank. This creates an in-tank atmosphere with less than 12 percent oxygen, far below the 21 percent level found in the outside air, and far too low to enable any fuel vapors to ignite.

Honeywell developed the ASM kit in response to operator concerns about the standard ASM’s service life, which averages about three years or between 9,000 and 12,000 hours of operation. By installing our kit operators can more than double on-wing time.

We’re so sure of our reliability of our upgraded ASM that Honeywell offers a full seven-year warranty, enabling airlines to incorporate routine ASM change-outs into their regularly scheduled heavy-maintenance intervals. In addition, the Honeywell ASM outperforms the installed OEM module by about 120%, even near the end of its service life.

Valve Improvements Improve Engine Reliability

Honeywell has more than five decades of experience designing and manufacturing high-performance valves to make aircraft engines safer, more efficient and more reliable.

Our valves provide precise, reliable control of critical engine functions for turbine clearance control, compressor bleed, anti-ice and engine start. The Honeywell engine valve portfolio includes more than 900 unique valve designs that are used on most airliners and many other aircraft types.

Honeywell engineers are dedicated to improving valve performance, reliability and durability. For example, they redesigned the temperature control valve (TCV) for the Boeing 737 environmental control system, which has reduced unscheduled removals by 20-50%. These improvements were achieved by upgrading the actuator assembly to eliminate a major valve wear-out mode and including an improved capacitor with increased temperature rating for longevity.

We also improved the expected service life for our pre-cooler control valve (PCCV), which flies on the Boeing 737NG. The re-engineered PCCV valve eliminates the mechanical feedback system and moves vibration response away from engine frequency, expanding predicted reliability to 20,000 hours mean time between failures (MTBF) compared to the previous valve’s expected lifecycle of 8,000 hours. More than 3,000 PCCVs have been delivered to more than 40 different airlines since 2016.