Gate 41Things that look scary but have an explanation
Why do the wings flex?
That wing is bending. Is it supposed to do that?
A wing is a long, strong, springy beam. In flight it carries the whole aircraft, so the tips rise relative to the roots: tens of centimetres on a short-haul jet, a few metres on the largest long-haul wings. On the ground the wings droop slightly instead, under the weight of fuel and engines.
The flex is deliberate. A bendy wing spreads loads smoothly instead of concentrating them at the root, soaks up gusts and weighs less than a rigid one.
Before an aircraft type is certified, a test wing is bent upward to 150% of the greatest load it should ever meet in service, and it has to hold. Fatigue tests then simulate many lifetimes of flights.
A little deeper
Fuel stored in the wings helps too: its weight pulls against the lift, which reduces the bending at the root. That is one reason fuel is used from tanks in a planned order.
Some aircraft also use control surfaces to ease gust loads, moving automatically to soften bumps. Wings are inspected regularly for fatigue cracks, because strength is about repeated loads over decades, not just one big one.
Limits: flex is only reassuring because the design margins are tested and maintained. Engineers measure it; passengers just get the window seat.
See it in Gate 41, in the outside view
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People involved
- Kenji WatanabeAircraft maintenance engineer