Load factor

Load factor is how many G's the wing carries

Definition

Load factor is the ratio of the lift the wing is making to the airplane's weight — how many G's. In straight-and-level flight it's 1 G (lift equals weight). In a level turn the wing also has to pull the airplane around, so it makes more lift than weight: load factor = 1 ÷ cosine of the bank angle. That's about 1.15 G at 30°, about 1.4 G at 45°, and exactly 2 G at 60°.

Explanation

The wing must make lift equal to load factor × weight. Past about 45° the curve climbs fast — small increases in bank cost a lot of G.

Figure 5-53. Angle of bank changes load factor in level flight. — Figure 5-53 · FAA-H-8083-25C, Pilot's Handbook of Aeronautical Knowledge (p. 131)

Why it matters

A 60° steep turn makes the airplane 'weigh' twice as much to the wing. That extra lift demand is exactly why steep turns feel heavy — and why the next slide's stall speed climbs.

From the Right Seat

I have students watch the G-feel and the back-pressure grow together as they roll into a steep turn — load factor is something you can feel, not just a number.

A DPE might ask

What is the load factor in a level 60° banked turn?
How does the wing's lift requirement change as you bank?

PHAK ch. 5 — Load factors

Why it bites: stall speed and Vₐ

Definition

Higher load factor raises the stall speed: stall speed goes up with the square root of the load factor. At 2 G the stall speed is about 1.4× its 1-G value — which is why you can stall at cruise speed in a 60° turn.

Explanation

The wing still stalls at its critical angle of attack; the load factor just makes you reach it at a higher airspeed. Maneuvering speed (Vₐ) is the speed at or below which the wing will stall before the airframe is overstressed — an abrupt full control input or a strong gust makes the wing stall instead of bending the airplane. Vₐ is lower when the airplane is lighter.

Why it matters

This is the quantitative backbone of the stall lesson and the base-to-final case study: it's the angle that stalls the wing, and load factor is what sneaks the stall speed up on you.

Common error

Students think load factor is an aerobatics-only concern. It isn't — a routine 60° steep turn already pulls 2 G, and any abrupt pull-up or turbulence adds load. That's why we respect maneuvering speed and don't yank the controls at high speed.

How much load factor does a level 60° banked turn produce?

Safety

At or below maneuvering speed, full or abrupt control inputs are protected by the wing stalling first. Above it, you can exceed the airplane's limit load — so slow to Vₐ in turbulence.

A DPE might ask

What does maneuvering speed (Vₐ) protect against, and how does weight affect it?
Why does stall speed increase in a steep turn?

Airplane Flying Handbook — Maneuvering speed & load factor