Hand-Propping an Airplane: Reasons, Proper Techniques, and Safety Considerations
⚠️ Disclaimer:
This article is for informational and educational purposes only. Hand-propping an airplane is a potentially dangerous procedure that should never be attempted without proper training, supervision, and adherence to all applicable safety protocols. Improper technique can result in serious injury or death. Always consult with a certified flight instructor or experienced aviation mechanic before attempting any manual engine-start procedures.
When you think of starting an airplane engine, images of pushing a button or turning a key might come to mind. But in some aircraft—especially vintage planes, taildraggers, and small training aircraft—hand-propping an airplane remains an essential skill. This blog post explores why pilots hand-prop planes, how to do it safely, and the risks involved. Whether you're a student pilot, aircraft owner, or aviation enthusiast, understanding this lost art of manual engine starting is valuable and, in some cases, necessary.
What Is Hand-Propping?
Hand-propping is the process of manually starting an aircraft engine by physically turning the propeller by hand. This method is mostly used for older aircraft that lack electric starters or when the starter system fails.
Hand-propping is both simple and risky. A successful hand start requires proper technique, training, coordination, and strict adherence to safety protocols.
Why Would You Hand-Prop an Airplane?
While modern aircraft typically use electric starters, there are several reasons why pilots still need to hand-prop aircraft today:
1. No Electrical Starter Installed
Many classic and vintage aircraft were built before electric starter systems became standard. Planes like the Piper Cub, Taylorcraft, and early Cessna 120/140 models often don’t have electrical systems at all, making hand-propping the only way to start the engine.
2. Dead or Weak Battery
Even planes with electric starters may require hand-propping when the battery is weak or dead. This can happen after extended inactivity, in cold temperatures, or due to charging system failure.
3. Starter Motor Failure
If the starter motor fails—a common issue in older or high-time aircraft—the pilot may resort to hand-propping to avoid being stranded.
4. Emergency Situations
In remote areas or during backcountry flying, hand-propping can be a critical emergency skill. Pilots who fly off-grid may carry lightweight aircraft without starters to reduce weight and complexity.
5. Engine Maintenance Checks
Mechanics and owners sometimes hand-prop engines to test magnetos, check timing, or rotate the engine for oil circulation before startup—especially after long periods of inactivity.
Is Hand-Propping Legal?
Yes—but with conditions. The FAA permits hand-propping, but FAR 91.13 prohibits careless or reckless operation. That includes unsafe starting procedures.
There is no specific FAA regulation that applies to hand propping an airplane, either to prohibit it or to direct how it is to be done. It's an action that can be accomplished safely. For many of us who operate airplanes without starters, it is commonplace and, of course, necessary in order to go flying. (Mar 25, 2015)
Airport rules, insurance policies, and flight school guidelines may prohibit or restrict hand-propping due to safety and liability concerns. Always check with local authorities or facility operators.
Dangers of Hand-Propping
Before learning how to hand-prop an aircraft safely, it's important to understand the potential dangers involved:
1. Injury or Death
The spinning propeller is extremely dangerous. Even a slow-moving blade can break bones or sever limbs. A misstep could result in life-altering injuries or fatal accidents.
2. Unsecured Aircraft
If the aircraft is not properly chocked or braked, it can lurch forward when the engine starts—possibly dragging the propper into the propeller arc or crashing into obstacles.
3. Engine Starts at High RPM
Incorrect throttle or mixture settings may cause the engine to start at high power, causing the aircraft to leap forward uncontrollably.
4. No One in the Cockpit
Without a person in the cockpit to manage throttle, brakes, or mags, there's no one to shut the engine down if something goes wrong. This is a major safety violation. There are a number of videos available on the internet that graphically show what can happen when proper safety measures are not employed, and an unsecured aircraft is started without a properly briefed safety pilot in the cockpit.
How to Hand-Prop an Airplane Safely: Step-by-Step
⚠️ Disclaimer:
Hand-propping should only be done by trained individuals using proper procedures and under controlled conditions. Never attempt it without prior instruction.
Step 1: Pre-Brief the Assistant (Cockpit Operator)
You must have a qualified person in the cockpit to handle the controls. Their duties include:
· Setting brakes
· Verifying throttle at idle
· Checking mixture (usually full rich)
· Master switch ON (if needed)
· Mags set to "BOTH"
· Calling out: “BRAKES SET – THROTTLE IDLE – READY TO PROP”
Step 2: Secure the Aircraft
· Use chocks on both main wheels.
· Tie down the tail if possible.
· Ensure parking brake is engaged.
Step 3: Propeller Area Safety Check
· Make sure no one is near the propeller arc.
· Clear any loose objects nearby.
· Double-check your surroundings.
Step 4: Positioning Yourself
Stand with feet firmly planted on solid ground. Position your body to the side of the propeller arc, not directly in front. Use the "blade walk" technique to bring the prop to the starting position (usually just past top dead center).
Step 5: Call Out Before Propping
Loudly announce:
“CLEAR PROP!”
Wait and look for anyone who might not have heard. Never skip this step.
Step 6: Grasp the Blade Properly
Grip the blade near the hub with your fingertips. Your palm should be open, fingers wrapped around the back edge. Don’t curl your fingers in front of the blade.
Never wear gloves when hand-propping.
Step 7: Pull Down Smoothly
Using a smooth, downward motion, pull through with your legs and arm together, stepping away from the arc immediately after the pull.
Never "crank" or "spin" the prop.
Step 8: Monitor the Engine Start
Once the engine fires, the cockpit assistant must:
· Verify throttle is at idle
· Monitor engine RPM
· Prepare to shut down engine immediately if anything is wrong
Tips for Specific Engine Types
Continental Engines (e.g., A65, O-200):
Usually start easily with throttle idle, mixture full rich, and one or two primes. Some require the left magneto grounded until just before start for safety.
Lycoming Engines (e.g., O-235, O-320):
May require more priming. Be cautious of flooding. Use primer instead of pumping the throttle to avoid backfires.
Magneto Considerations:
Make sure you understand if the engine uses an impulse-coupling magneto, shower of sparks, or retard-breaker mag system. These affect the timing and technique.
Common Mistakes to Avoid
1. No One in the Cockpit – This is extremely dangerous and often illegal.
2. Incorrect Throttle Setting – Can cause engine to start at high RPM.
3. Failing to Announce “Clear Prop” – Risking injury to bystanders.
4. Using improper swing-through technique. I was taught to raise my right foot, swing through to my right. My momentum would take me away from the propeller as the engine started. This technique also assured that if I should slip and fall, I would be falling away from the turning prop. I’ve seen people raise their left foot. When they pull down, it is like they are bowing toward the now-turning propeller. Dangerous at best. At worst, should the slip and fall, they fall into the propeller.
5. Improperly briefed person in the cockpit. You need the person in the cockpit to understand that they are there as a safety precaution. If anything goes wrong, they can pull the mixture to kill the engine. I actually saw one private pilot ask a flight instructor to hand prop his airplane for him. The pilot sat in the cockpit, and just as the instructor put his hand on the propeller blade to pull it through, he turned the key to activate the starter. Luckily, no one was hurt, but it could have been a disaster. I’m sure the instructor assumed that the private pilot was familiar with the procedure, but a briefing would have prevented a dangerous situation. NEVER ASSUME the other person knows anything. You don’t have to talk down to them. Just say in a respectful way, “Let’s go over a couple things, so we’re all on the same page …” and then cover the safety procedures.
During my aviation career which covered a span of 37 years, I probably only hand-propped four or five airplanes, but I was confident when I did it, because I had been properly trained, adhered to established safety measures, and took the time to brief the other pilot.
It’s easy to say, “I would never do that. If I had a dead battery I’d get a mechanic to do the necessary repairs.” That’s exactly what you should do … IF that option is available. But NEVER SAY NEVER! You don’t know what situation you may find yourself in someday, or late some night, on a remote airstrip. It’s a good idea to get the proper training now, and not have to try to find a YouTube video when you are in an area of spotty coverage, or worse yet, teach yourself with no one there to help you.
Bad training is just as bad - or worse - than no training. Make sure the person teaching you knows what he or she is doing.
Be safe. ALWAYS!