Moving an aircraft on the ground without its engines running — a process called towing — is one of the most routine yet potentially hazardous tasks an aviation maintenance technician (AMT) performs. Unlike taxiing under pilot control, towing places responsibility for the aircraft's safety entirely on ground personnel. Improper towing technique can result in landing gear damage, nose-gear shimmy link failures, fuselage stress, runway incursions, or serious injury to workers and bystanders. Understanding the correct procedures, the applicable limitations, and the precautions involved is essential for any AMT and is directly tested on the FAA General Knowledge exam.
This article covers towing fundamentals as described in FAA maintenance guidance and standard industry practice, so you understand not just the steps, but the engineering reasons and safety logic behind each one.
Why Aircraft Towing Is Different From Driving a Vehicle
An aircraft's ground steering geometry is engineered for flight — not for the leverage forces imposed by a tow bar attached to the nose gear or main gear. The nose gear, in particular, is designed to absorb vertical runway loads, not the large lateral bending moments that can occur if a tow bar is pushed or pulled at an extreme angle. Every aircraft has a published maximum tow bar turning angle (sometimes called the nose-gear steering limit), and exceeding it can fracture internal shimmy dampers, shear tow-lug attach points, or twist the drag brace. These limits are always specified in the aircraft's maintenance manual or aircraft flight manual, and the AMT must consult that documentation before beginning any tow operation.
Additionally, aircraft tires — especially nose gear tires — are inflated to much higher pressures than automobile tires and can be damaged by sharp turns at speed or by rolling over ramp debris. The combination of high tire pressure, relatively narrow gear track on many light aircraft, and a high center of gravity means the aircraft can be surprisingly easy to tip or pull sideways if towing speed and direction are not carefully managed.
Pre-Tow Preparation
Before connecting the tow bar or tug, the AMT must complete a deliberate set of checks. Skipping any of these steps is the most common source of towing accidents.
- Consult the maintenance manual. Confirm the approved tow points, maximum nose-gear steering angle, any tow-speed limitation, and whether the aircraft requires a specific type of tow bar (single-point nose-gear bar, dual-point main-gear bar, or a towbarless tug system).
- Clear the area. Walk the intended tow path completely. Remove wheel chocks, ground power cords, oxygen hoses, fuel nozzles, pitot covers, control locks, and any other equipment attached to or near the aircraft. Verify that hangar doors and ramp areas are fully clear of obstructions.
- Install the tow bar correctly. Connect the tow bar to the published tow fitting — never to the landing gear strut barrel, gear door hinges, or any structural fitting not approved for towing. Ensure all locking pins are fully seated and safety-pinned where required.
- Release the parking brake. The parking brake must be in the released position before towing begins. Towing against set brakes is a serious error that can overheat brake assemblies, damage brake linings, and flat-spot tires. Some aircraft parking brake systems can hold enough force to shear a tow bar fitting.
- Station wing walkers. For all but the smallest aircraft, at least two wing walkers should be positioned at or near each wingtip to watch clearances from buildings, other aircraft, ground equipment, and fuel pits. Wing walkers must remain in the tow driver's line of sight at all times and use standardized hand signals.
- Assign a cockpit attendant when required. Many aircraft require a qualified person in the cockpit during towing to operate the brakes if the tow bar fails or the tug loses control. This person should not attempt to steer using the rudder pedals on a nose-gear aircraft while a tow bar is connected, as this can bind the gear against the tow bar and cause structural damage.
Conducting the Tow
Once all pre-tow checks are complete, the operation itself must be performed slowly and deliberately. Speed is the enemy during ground towing. Most maintenance manuals specify a maximum tow speed — typically walking pace (approximately 3–5 mph) — because higher speeds dramatically increase the stopping distance and the side-load forces on the gear during turns.
Communication is continuous throughout the operation. The tow driver, the cockpit attendant (if present), and all wing walkers must use a pre-briefed set of hand signals. Standard signals include move forward, move rearward, turn left, turn right, stop, and emergency stop. A single worker raising both arms with palms outward — the universal stop signal — must cause the tow to stop immediately, with no questions asked.
During the tow, the driver must continuously monitor the nose-gear angle relative to the aircraft centerline. Most tow bars include a shear fitting or a mechanical stop designed to break or limit travel before the nose gear is damaged; however, these are last-resort protection devices, not substitutes for proper technique. When turning in tight areas, make wide arcs rather than sharp pivots. If the turning radius required exceeds the aircraft's published limit, reposition the tug rather than forcing a tighter turn.
When towing an aircraft into or out of a hangar, slow to the absolute minimum pace. Hangar sills (the raised door frame threshold) can catch low-hanging antennas or probe assemblies. Hangar floors often transition from asphalt to concrete at different heights, creating a bump that can jar landing gear if crossed too quickly. Assign a spotter to watch each wingtip as the aircraft passes through the doorframe.
Towing on Active Airport Movement Areas
If the tow path crosses a taxiway, runway, or any portion of the airport movement area, the operation becomes subject to air traffic control (ATC) jurisdiction. Personnel must obtain an ATC clearance before entering any movement area, use the correct radio frequency, and comply with all light gun signals or verbal instructions. Ground personnel on the ramp must be aware of jet blast hazards from taxiing aircraft and must never tow an aircraft in front of an aircraft under power without clearance and positive confirmation that the taxiing aircraft has stopped.
Aircraft towing operations near runway hold-short lines require the same vigilance as any surface movement. The FAA emphasizes in AC 91-73 (Parts 91 and 135 Air Taxi & Commercial Operator Safety) that runway incursions during towing operations are a significant safety risk, and ground crews must treat hold-short markings with the same respect as a pilot would during taxi.
Post-Tow Procedures
When the aircraft reaches its final position, the process is not finished until every securing step is complete:
- Set the parking brake or install chocks — or both, as required by the maintenance manual.
- Disconnect and stow the tow bar, inspecting it for any bends, cracks, or damaged fittings before storage.
- Reconnect any equipment removed during pre-tow preparation (pitot covers, control locks, ground power if needed).
- Conduct a walk-around inspection of the landing gear, tow fittings, and tires to confirm no damage occurred during the tow.
- Document the operation in the aircraft maintenance record if any discrepancies were found.
Key Numbers and Rules
- Always consult the aircraft maintenance manual for the specific nose-gear turning angle limit before towing — there is no universal standard angle across all aircraft types.
- Maximum tow speed is typically walking pace (~3–5 mph); never exceed the manufacturer's published limit.
- Parking brake must be released before the tow begins — towing against set brakes risks heat damage and structural overload.
- Tow fittings only — never attach a tow bar to an unapproved fitting such as a landing gear strut or door hinge.
- ATC clearance required before entering any movement area during towing on a towered airport.
- Wing walkers required whenever clearance between the aircraft and obstacles is less than can be safely judged by the tow driver alone — and always for large or wide-body aircraft.
Common Test Traps
- Towing with parking brake set. The FAA knowledge test may describe a scenario where chocks are removed but the parking brake is still set. The correct action is always to confirm the brake is released before any movement begins.
- Using an unapproved tow point. Test questions may show a tow bar connected to a gear strut or a tie-down ring and ask whether this is acceptable. It is not — only manufacturer-approved tow fittings may be used.
- Exceeding the nose-gear turning limit. Exam questions emphasize that the steering limit during towing is typically less than the aircraft's normal ground steering range under pilot control, because tow bar side loads are much greater.
- Forgetting the cockpit attendant requirement. Some aircraft require a person at the brakes during towing. Failing to position one when required is a procedural error that the exam tests.
- Entering a movement area without clearance. Any tow operation crossing a taxiway or runway requires ATC coordination. Treating it as a ramp-only operation and omitting the clearance step is a frequently tested oversight.