The 5-Minute Post-Crash Protocol
A bad crash is disorienting. You walk to the quad, heart pounding, mind racing through what might be broken. Without a systematic approach, you’ll miss things — a cracked arm, a partially disconnected antenna, a motor with one bent bell. This protocol turns chaos into a checklist. Run through it every time, in order. It takes 5 minutes and catches problems before they become mid-air failures.
Step 1: Power Down Immediately (0:00-0:05)
If the quad is still powered after the crash, unplug the battery immediately. A stalled motor or shorted ESC will cook itself in seconds. If you can’t reach the plug (quad in a tree, submerged), the priority is cutting power before anything else. For water crashes, unplug immediately and DO NOT power on again until fully dry (48+ hours in rice/silica).
Step 2: Visual Frame Inspection (0:05-1:00)
Grip the quad and apply gentle twisting force to each arm. A cracked arm will flex more than the others or make a creaking sound. Check:
- Carbon delamination: Look for white/gray patches on the carbon edges — this is delamination, the carbon layers separating. Replace the arm.
- Standoff damage: Bent or cracked aluminum standoffs. These are cheap to replace and critical for frame rigidity.
- Motor bell play: Grab each motor bell and try to wiggle it side-to-side. Any play beyond a barely perceptible click means a bent shaft or worn bearing.
- Print check: If you have 3D printed parts (GoPro mount, antenna holder), inspect for layer separation. TPU survives crashes well; PLA and PETG crack.
Step 3: Propeller Check (1:00-1:30)
Spin each prop by hand. Look for:
- Tracking: Watch the tip of each blade as it spins. If one blade tracks higher than the others, the prop is bent. Replace it — a tracking prop causes vibration that can destroy motor bearings.
- Cracks at the hub: The most dangerous prop failure mode. A crack radiating from the center hole will cause the prop to explode at high RPM. Replace any prop with hub cracks immediately.
- Nick damage: Small nicks on the blade edge are cosmetic. Large chunks missing (3mm+) will cause imbalance. When in doubt, replace the set — props are the cheapest component on the quad.
Step 4: Electrical Check with Smoke Stopper (1:30-2:00)
ALWAYS use a smoke stopper for first power-up after a crash. A Vifly ShortSaver or DIY 2A fuse inline with the battery prevents ESC/motor damage if something shorted. Procedure:
- Connect smoke stopper between battery and quad
- Plug in battery
- Watch the smoke stopper LED: steady green = OK, red/blinking = short detected
- If short detected, unplug and hunt for the bridge before proceeding
If smoke stopper passes, listen for the ESC startup tones. All 4 (or 8) ESCs should chime. A missing chime means that ESC isn’t powering up — check motor wire connections to that ESC.
Step 5: Motor Test (2:00-3:00)
In Betaflight Motors tab, spin each motor individually at 1050 (just barely spinning). Listen for:
- Scraping/grinding sound: Debris in the motor or a bent bell rubbing the stator. Disassemble the motor to clean.
- Intermittent stops: Bad ESC or broken motor winding. Swap that motor to a known-good ESC position to isolate.
- Motor not spinning at all: Check the three motor wire connections at the ESC. Reflow if suspect.
Spin each motor to 1300 and watch for vibration. Place a fingertip on the arm — excessive vibration indicates a bent shaft, bad bearing, or unbalanced prop.
Step 6: Video System Check (3:00-4:00)
Power on your goggles. Check:
- Video signal present? No video = check O4/VTX power, antenna connection, camera cable
- Image clear? Blurry or dark = camera lens dislodged or damaged
- OSD working? Missing OSD = check FC-VTX wiring (UART MSP connection)
- Antenna secure? U.FL/IPEX connectors pop off in crashes. They click when properly seated — if it slides on without a click, it’s loose
Step 7: Radio Link Check (4:00-4:30)
With the quad powered and radio on, check RSSI/LQ in the OSD. Walk 30 feet away with your body between the radio and quad. LQ should stay at 100. If it drops, your receiver antenna may be damaged or disconnected. ELRS ceramic antennas can crack invisibly; a drop in LQ is often the only symptom.
Step 8: Test Hover (4:30-5:00)
Arm the quad. Hover at eye level for 30 seconds. Listen for:
- Unusual motor noise: New rattles or whines = bearing damage
- Oscillation: Visible shake in the hover = bent prop, loose motor, or cracked arm changing resonance
- Drift: Quad drifting in angle mode = gyro may need recalibration after a hard impact
If the hover is clean, do a gentle punch-out to 50% throttle and listen for oscillations at higher RPM. If everything passes, you’re cleared to fly.
Field Repair Kit: What to Carry
Build a small kit that lives in your bag. Every item here has saved a flying session:
- Props (4+ full sets): The most common failure. Don’t be the pilot who goes home after one broken prop.
- M2 and M3 hardware kit: Screws, standoffs, nuts. At least 10 of each common size.
- Zip ties (assorted): Temporary fixes for broken 3D prints, antenna mounts, or battery straps.
- Electrical tape: Secures loose wires, protects cut insulation.
- Hex drivers (1.5mm, 2mm, 2.5mm): For motor screws, frame screws, and stack hardware.
- Prop tool (8mm/10mm): For prop nuts. Using pliers destroys the nylon lock.
- Multitool with pliers: For bending things back and gripping small parts.
- USB cable: For Betaflight access in the field.
- Spare battery strap: Ejected batteries from broken straps are a common crash cause.
- Portable soldering iron (Pinecil): If you fly remote locations. A broken motor wire in the mountains ends your day without it.
Pre-flight after repair: Always do a full arming check (arm, hover, gentle punch) after any field repair, no matter how minor. The most dangerous crashes happen on the “quick test flight” after a rushed repair.