Jet Engines: How They Work and Why They're So Reliable
2 min read
The short answer
Jet engines are some of the most reliable machines ever made. They're tested against birds, ice and extreme conditions before they carry passengers, and they're monitored on every flight. Even if one stops, the plane flies safely on the other.
One of the Most Reliable Machines Ever Built
Jet engines are among the most dependable machines people have ever made. Knowing how they work — and how they're tested — can replace vague worry with real confidence.
How a Jet Engine Works
A modern airliner engine works in four steps:
- The fan — the big fan at the front pulls in air. Most of that air flows around the engine's core. It gives most of the push, and keeps the engine quieter and more efficient.
- Squeezing — rows of spinning blades squeeze the rest of the air to up to 40 times normal air pressure.
- Burning — fuel is added and lit, and the hot gas expands rapidly.
- Spinning — the expanding gas spins more blades, which drive the fan. What's left rushes out of the back as thrust.
Everything inside spins smoothly in one direction. There are no parts moving back and forth, as there are in a car engine. That's a big reason jet engines are so reliable.
The Reliability Numbers
The FAA has cited a jet engine failure rate of about one per 375,000 flight hours. For piston engines, it's one per 3,200 hours — so jet engines are more than 100 times more reliable.
One engine type has gone 200,000 hours on average between unplanned shutdowns in flight. And GE's airline engines are ready to fly on schedule more than 99.97% of the time.
Tested to the Extreme
Before any engine carries passengers, it must pass tough tests set by the FAA and EASA:
- Birds — it must keep running after swallowing birds of set sizes
- Blade containment — if a fan blade breaks, the engine casing must hold it in
- Ice — it must run safely in icing conditions
- Crosswinds — it must start and run in very strong side winds
- Endurance — it must run for hundreds of hours at maximum power
Flying on One Engine
Every airliner can keep flying safely if an engine stops. A twin-engine jet can take off, climb, cruise and land on one engine. Pilots practise this regularly in the simulator.
Watched on Every Flight
Modern engines send performance data to the airline during the flight. Anything unusual is flagged straight away. Small issues are then fixed during routine maintenance — long before they could affect a flight.
The Bottom Line
The engines on your plane are among the most tested, monitored and reliable machines on Earth. And even if one stopped, the plane would carry on safely.
Sources
- FAA, Turbine Engine Failure Rate (cited in Wikipedia, Turbine engine failure): https://en.wikipedia.org/wiki/Turbine_engine_failure
- GE Aerospace, Commercial Engine Status Report: https://www.geaerospace.com/news/press-releases/commercial-engines/ge-aircraft-engines-commercial-engine-status-report
- FAA, 14 CFR Part 33 — Airworthiness Standards: Aircraft Engines: https://www.ecfr.gov/current/title-14/chapter-I/subchapter-C/part-33