My drone crashed -- what should I do next?
I crashed my Holy Stone HS720E for the first time today. I was flying near a tree line, a gust of wind caught it, and it hit a branch and fell about 15 feet to the ground in the grass. Outwardly it looks mostly okay -- no obviously broken pieces. But I am not sure what to check before flying it again, or whether it is even safe to fly. What is the standard post-crash inspection process?
5 Answers
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HobbyistHank
Best Answer
First: do not fly again immediately. Power the drone off if it is still on, then work through this inspection checklist:
Post-crash inspection checklist
- Battery first: Remove the battery and inspect it. Look for swelling (the battery appears puffy or soft), cracks in the casing, or any heat. If the LiPo battery is swollen or cracked, do not charge it and do not fly with it. Place it in a fire-safe bag or container and take it to a battery recycling facility. Order a replacement before flying again.
- Propellers: Inspect all four propellers closely under good light. Look for cracks, chips, bends, or any deformation. Even hairline cracks that are barely visible can cause vibration and mid-air failure. Replace any prop that shows any damage at all. Replacement props for the HS720E are cheap ($5-10 for a 4-pack) and easy to swap.
- Motor arms: Flex each arm gently. Look at where it attaches to the body for cracks. If an arm is bent or cracked, the drone is not safe to fly until it is replaced.
- Motors: Spin each motor by hand. It should spin freely and smoothly. Any grinding, roughness, or resistance indicates possible motor or shaft damage.
- Camera/gimbal: Check for obvious physical damage. If the gimbal moves unevenly or makes noise during startup, it may have been bent.
- Power-on test: After physical inspection passes, power on and listen. During motor spin-up, all four should sound the same. Unusual buzzing, clicking, or vibration from one motor suggests damage.
- Low hover test: If everything sounds normal, fly at 3-4 feet for 60 seconds and watch for unusual drift, wobble, or behavior before flying normally.
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SafetyFirstPilot
The battery point cannot be overstated. LiPo (lithium polymer) batteries are the component most likely to cause a serious problem if damaged, and impacts can damage them internally even without visible external damage.
The squeeze test: Remove the battery and gently squeeze it along its length. A healthy LiPo feels firm and rigid. If it feels soft, squishy, or puffy in any area, it has likely developed internal gas from an impact-induced short or cell damage. This is a fire hazard.
A battery that passes the squeeze test immediately after a crash may still be compromised. Watch it during the first charge after the crash. If it shows unusual heat or swells even slightly during charging, stop charging immediately.
Never leave a LiPo battery charging unattended after it has experienced an impact. This is standard LiPo safety practice, but it is especially important after a crash.
GearReviewer_Tom
After a tree impact, the statistical breakdown of most common damage in order of frequency:
- Broken/damaged propellers: The most common result of any collision. Even a glancing hit can chip a blade. Always replace -- they are cheap and a compromised prop is dangerous.
- Bent motor shafts: Less visible but causes consistent vibration during flight. If the drone vibrates noticeably more than before the crash, motor shafts are suspect.
- Cracked motor arms: Most visible where the arm meets the body of the drone. Sometimes only visible when you flex the arm slightly.
- Battery damage: May not be visible but should always be checked after any fall.
- Camera/gimbal misalignment: The gimbal can absorb an impact and be knocked out of calibration even without obvious physical damage.
For the HS720E, all of these parts are available as replacements on Amazon. Even a significant repair cost is far less than buying a new drone, so do not write it off without investigating.
DroneInspector_Pro
One overlooked item: compass recalibration after a significant crash. The magnetometer (compass) in a GPS drone can be affected by a hard impact, particularly if the drone hit metal or a strong impact from a specific direction.
Signs of compass issues after a crash:
- Drone slowly rotates (yaws) in GPS hold mode when it should be stationary
- Erratic movement in the first few seconds after takeoff
- Drifts in an unexpected direction in GPS mode
- RTH takes an incorrect heading or overshoots the home point
If you notice any of these after a crash, perform a compass calibration following your drone's manual before flying further. For the HS720E this is done in the app settings under calibration. Do not skip this step even if the physical inspection passes -- GPS behavior issues from a bad compass are subtle until they become a problem.
CasualFlyer_Lisa
Practical Holy Stone HS720E tips specifically:
- Replacement propellers: Search "Holy Stone HS720E propellers" on Amazon. A 4-pack runs $6-10. The HS720E uses 5030 propellers (2 CW, 2 CCW) -- make sure you order the correct rotation direction sets.
- Holy Stone customer support: If the drone is relatively new and the crash was due to a malfunction (rather than pilot error), contact Holy Stone support at their website. They occasionally provide replacement parts for recent purchases, especially under warranty conditions.
- Learning from the crash: A gust-induced tree collision is a classic wind awareness lesson. Before your next flight, check the wind speed in the area. Anything above 10-12 mph sustained while learning is risky, especially near obstacles.
Crashes are part of the learning process -- every pilot has had them. What matters is the safe inspection before returning to flight, and understanding what led to the crash. For tips on reading wind conditions and adjusting your flying accordingly, check out our first flight guide which covers weather assessment.