5 Things to Check Before Every Flight

You’ve spent weeks — maybe months — on this build. The airframe is perfect. The electronics are wired. The paint job looks clean. You drive out to the launch site, set up on the pad, and somewhere in the excitement of flight prep, you skip a step.

That’s where things go wrong. Not because rocketry is unforgiving — but because the basics get lost in the rush to fly.

This isn’t a complete preflight procedure. It’s the five most critical areas that account for the vast majority of field failures. Get these right, and you’ve eliminated most of what can go wrong on launch day.

Check #1: Recovery System

This is the single biggest failure point in high-power rocketry. A rocket that goes up will come down. The only question is whether it comes down under a parachute or as a lawn dart.

Recovery failures come in a few flavors: the parachute is packed too tight and can’t deploy, the ejection charge is too small (or too large), shear pins are the wrong size, or the shock cord tangles around the chute on its way out. Every one of these is preventable at the pad.

• Ground-test your ejection charges. Every time. A charge that worked last flight may not work with a tighter pack job.
• Pack the chute loosely. If you’re forcing it in, it’s too tight. Use wadding or a Nomex blanket, and make sure nothing is binding.
• Verify shear pins. The right number, the right size. Too many and the charge can’t separate the sections. Too few and you get premature separation.
• Check the shock cord for damage. Frayed Kevlar, melted elastic, or a cord that’s too short for the airframe — all recipes for a zipper or a yard sale.

Check #2: Electronics

Your altimeter is the brain of the operation. It decides when to fire the ejection charges, and if it’s not working right, nothing else matters.

Electronics failures are sneaky. Everything looks fine on the bench, but 14 g’s of acceleration and vibration have a way of finding every weak solder joint, every loose connector, and every battery that’s just barely under voltage.

• Check battery voltage. A 9V battery should read 9.2V or higher. If it’s at 8.7V, replace it. Don’t gamble on marginal power.
• Verify continuity on every e-match. Use your altimeter’s built-in continuity check. If it doesn’t beep, don’t fly.
• Confirm the altimeter is reading ground level. Listen for the beep code. Make sure it’s reporting the right altitude and the correct number of charges.
• Secure all wiring. Zip ties, tape, or cable routing — nothing should be free to move under acceleration. A loose wire at max-Q is a failed deployment.

Check #3: Structural Integrity

Your rocket is about to experience forces it never sees on the workbench. Acceleration, drag, vibration, and deployment loads all test the structure in ways that are hard to simulate by hand.

If it flexes on the ground, it’s coming apart in flight. That’s not a maybe — it’s physics.

• Inspect every fin fillet. Look for cracks, especially at the root. Transport is brutal on fillets — check them at the field, not just in the shop.
• Check rail buttons or launch lugs. Are they tight? Aligned? A loose rail button can jam on the rail and send the rocket off at an angle.
• Verify coupler and section fit. Sections should slide together firmly but not bind. Too loose and you risk separation under drag. Too tight and ejection can’t push them apart.

Check #4: Motor Installation

This sounds basic, but motor problems are more common than most people think. Wrong motor, wrong adapter, wrong igniter depth, wrong retention — any one of these can turn a clean flight into a bad day.

• Confirm the correct motor. Check the designation against your sim. The motor you packed might not be the motor you planned to fly.
• Check retention. Motor retention hardware should be secure. If you’re using a friction-fit system, make sure it’s actually tight — not just “feels okay.”
• Seat the igniter properly. The igniter should be inserted to the correct depth and held in place. A shallow igniter means a misfire or a delay in ignition.

Check #5: Know Your Flight

This is the one most people skip, and it’s the one that separates experienced fliers from everyone else. Before you put the rocket on the rail, you should already know what’s going to happen.

Your simulation tells you the expected altitude, max velocity, optimal delay, stability margin, descent rate, and drift. If you don’t know those numbers, you’re flying blind.

• Review your simulation. Run it with the day’s actual conditions — wind, temperature, launch site altitude. Sim numbers from last month aren’t today’s numbers.
• Check your stability margin. At least 1.5 calibers for most HPR flights. If you’re below that, you’re rolling the dice.
• Know your descent rate. A heavy rocket under a small chute comes down hard. A light rocket under a big chute drifts into the next county. Match the chute to the weight.

The Bottom Line

None of these checks are complicated. None of them take more than a minute each. But together, they cover the failure modes that account for the overwhelming majority of bad flights.

Build a checklist. Print it out. Laminate it. Throw it in your range box. And use it every single time — not because you’ll forget, but because one day you’ll be tired, or rushed, or excited, and the checklist will catch what your brain misses.

Fly safe. Fly smart. Fly higher.

— The Rocket Doctor