Quick Answer
After every FPV crash, run a five-step check: inspect the frame for hairline cracks, spin each motor and listen for grinding, plug into Betaflight and verify the gyro responds, power your VTX and check video, then do a low hover test. Skipping any of these is how small damage becomes a total write-off on the next flight.
What Actually Breaks
We've had hundreds of crashed drones through our workshop. On a 5-inch build hitting concrete at 30 mph, the first casualty is a propeller, then a bent motor bell or cracked arm. Frames like the Axisflying Manta 5 SE V2 use 4mm carbon that survives most impacts, but we see compression delamination where the arm meets the body plate.
The less obvious damage is what catches people out. A motor that spins freely on the bench but has a shifted magnet gap will overheat within 60 seconds of flight. Our workshop rule: if the crash was hard enough to flip the quad, we reflow every motor wire joint before flying again.
The Five-Step Checklist We Run After Every Impact
1. Frame Inspection
Remove the props and hold the frame to a bright light. Hairline carbon fractures are translucent. We mark suspected cracks with a silver pen and flex the arm. If the mark spreads, the arm is done.
2. Motor Spin Test
Spin each motor by hand. It should rotate smoothly with no clicking. A bent bell produces a periodic scraping. If anything feels off, remove the bell and check for shaft bend. We keep spare 5x3 props and bells on the bench for this reason.
3. Flight Controller Check
Plug into the SpeedyBee F405 V5 stack and connect to Betaflight. Move the quad in the Setup tab. The 3D model should respond instantly. If it drifts while the quad sits still, your gyro took an impact. We see more post-crash failures from loosened ribbon cables than from actual component damage.
4. Video System
Power on your VTX and check your goggles. Look for static lines, colour shifts, or intermittent dropouts. A partially sheared SMA connector is easy to miss. If the signal cuts when you pick up the quad, the antenna feed is compromised.
5. Hover Test
If everything passes, hover at 0.5 m for 15 seconds. Watch for vibration in the camera feed and listen to motor tone consistency. A sudden voltage sag under minimal load means a damaged connector or cell damage. Land and check motor temperatures. Any motor more than warm after a brief hover has a problem.
The Mistakes We See Most Often
The biggest error is flying again without checking. We've seen pilots burn an ESC in a single second flight because they skipped diagnosis. The second mistake is replacing props but ignoring a bent shaft. A 0.3mm bend is invisible but creates enough vibration to overheat the windings within two packs.
Don't forget the battery. LiPo cells punctured by standoff bolts show no external damage. If your battery hit hard, check cell voltages individually. Any cell more than 0.2V below the others is compromised. Our policy: if a pack took a direct impact, charge in a LiPo-safe bag on a non-flammable surface.
What We Keep in Our Field Kit
Every pilot in our workshop carries: spare props, a 1.5mm hex, a portable soldering iron, spare motor screws, and a USB-C cable. Under £40 and it has saved more builds than we can count.
FAQ
Q: Can I fly again if it still arms?
A: Arm is not a health check. A quad will arm with a bent motor, cracked frame, and damaged antenna. Always run the checklist.
Q: How do I know if a motor is bent?
A: Remove the prop, spin the bell, and listen for periodic scraping. A flat edge across the bell top will reveal wobble.
Q: Replace the arm or the whole frame?
A: Most 5-inch frames have replaceable arms. One cracked arm with intact centre plates? Replace just the arm. Cracks radiating from standoff holes on the main plate? Replace the frame. We stock replacement arms in our frame collection.
Q: Is this different from the build mistakes article?
A: Yes. That covers assembly errors during the build. This covers damage assessment after a crash. Different problems, different fixes.
Q: My quad won't arm after a crash. Where do I start?
A: See our won't arm troubleshooting guide. The most common post-crash cause is a disconnected receiver or a short from a damaged wire.
Q: My battery took a hit. Safe to charge?
A: Check each cell individually. Any cell 0.2V or more below the others, or any puffing, means retire it. Charge impacted batteries in a LiPo bag on concrete or metal. See our tools collection for safe charging accessories.