After a prop strike

Overview

Impact with object — what to check before next flight.

Betaflight/INAV, BLHeli32/Bluejay ESC, DJI consumer (closed stack).

Symptoms

Typical "After a prop strike" signs in flight, app or OSD:

• Bent prop
• Motor shaft play
• Gimbal error after touch
• Motor test without props — all spin evenly.

Common causes

Before replacing parts, rule out software, mechanical and environmental causes:

• Tree branch
• Ground strike
• Indoor collision

Tools needed

Prepare before diagnostics — saves time in the field:

• Prop removal tool
• Multimeter
• Blackbox log reader

Step-by-step fix

Work safely: battery off when working on ESC/motors; props removed; after repair — VLOS test flight.

• Replace ALL props; inspect motors for shaft bend.
• IMU + gimbal calibration.
• Blackbox review if FPV — check for desync.

Additional diagnostics

Motor test without props — all spin evenly.

Blackbox: desync, gyro noise, ESC temperature.

Prop balance — balance or replace in pairs.

When to contact service

If any of the following apply — do not fly and contact authorised service:

• Bent motor shaft or rough bearing — replace motor.
• ESC smells of burnt plastic — do not fly.
• After prop strike — gimbal/IMU error persists.

Prevention

Prevention reduces failure risk and supports EASA Open / VLOS compliance:

• Never fly with damaged props

Frequently asked questions

Is it safe to fly with "After a prop strike"?

No if the fault affects navigation, power, ESC or link. Fix on the ground first, then conduct a VLOS test flight in open area.

How long does diagnosis take?

Most “After a prop strike” cases — 15–45 min on the ground. Complex ones (firmware, hardware) may need 1–2 h and service.

Must I register repair with the NAA?

No mandatory repair registration, but a maintenance log is recommended for commercial operations.