When an emergency strikes in an aircraft, the pilots have only moments to respond with the correct actions to avert disaster. One of the most dangerous times for an airplane, known as a critical phase of flight, is the takeoff roll. During this time, the aircraft is on the ground and accelerating to a very high speed while in close proximity to many obstacles that it could collide with, resulting in disaster. Thus, it is an inherently risky time in the flying experience.

Professional airline pilots spend years of their careers training to understand a vast range of factors that influence an aircraft’s behavior, including performance, weather, aerodynamics, and hydraulics. The decision-making process actually begins before the aircraft enters the runway. During the departure briefing, the aircrew will explicitly establish a ‘Go, No-Go’ criterion that determines the conditions that will force a rejected takeoff. This establishes clear, objective boundaries, so there is no debate or hesitation in the high-stress moments before an RTO.

When And Why Pilots Reject Takeoff

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Rejected takeoffs are not a common occurrence in commercial aviation. However, the crew of every airliner is prepared to deal with the potential that it may be necessary on every flight. If the captain or first officer notices any abnormal condition during the acceleration down the runway, an RTO may be called. Common causes include caution lights in the cockpit, flaps or slats incorrectly configured, unusual vibration or engine readings, as well as discrepancies on sensors like airspeed indicators.

In the plane, either the first officer or the captain can be the pilot flying or the pilot monitoring. The difference is that the PF is the one actually on the controls, while the PM is providing support through additional instrument checks and procedural actions, and standing by to take over if necessary. To prevent split decisions, many airlines mandate that only the captain can initiate an RTO, even if the first officer is the PF.

There is a significant difference between high-speed and low-speed RTO. Low speed is generally considered below 80 to 100 knots in speed, whereas high speed is anywhere above that threshold to takeoff decision speed, called ‘V1.’ In a high-energy state, an RTO becomes dangerous because the brakes must absorb a massive amount of kinetic energy, which can immediately cause multiple tire blowouts and brake fires. Therefore, the causes are limited strictly to catastrophic, unflyable emergencies. Once the aircraft decelerates to a safe speed or a complete stop on the runway, the crew works to ensure the safety of the passengers.

When The Worst Case Scenario Unfolds

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Two seconds before the RTO, the aircraft is accelerating rapidly toward V1. The PF holds the thrust lever while the PM monitors the airspeed tape. Both pilots operate under strict high-speed reject criteria, only stopping for fire, engine failure, or an otherwise un-flyable aircraft.

In the event a catastrophic engine failure occurs one second before V1, the captain will recognize the master warning light, the fire indication, and the pull of asymmetrical engine power. As he decides to abort the takeoff and commands “REJECT,” the PF immediately pulls the thrust levers back to the idle stop to cut engine power. If the first officer was the pilot flying, the captain simultaneously physically takes control of the yoke and thrust levers.

The PF will apply maximum manual braking while the automated autobrake system simultaneously delivers full hydraulic power to the wheels. They will also pull the speedbrake lever to deploy the spoilers, which dumps aerodynamic lift and brings the full weight of the aircraft back down onto the tires for maximum grip. The PF then engages the reverse thrust to redirect engine airflow forward and increase deceleration.

The PM monitors the deceleration parameters and verifies that all automated systems are deployed properly, calling out a phrase like: “Speedbrakes up, Reversers normal.” They then transmit a radio message to the tower stating that the flight is rejecting takeoff.

Controlling A Jetliner After Failure To Launch

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Bringing a massive jet plane that weighs hundreds of thousands of pounds to a sudden halt from roughly 150 mph transfers an absolutely enormous amount of kinetic energy onto the brakes, tires, wheels, and landing gear. Managing this extreme thermal energy follows a precise procedural sequence to prevent tire explosions and main gear fires. The temperature of the wheel bogies can reach over 2,500°F (1,370°C) after a high-speed RTO. The captain will choose an area of the runway or taxiways to bring the airplane to a stop that is as distant as possible from other aircraft and potentially flammable surroundings.

The pilots will not use the parking brake if the temperature is high enough after aborting to prevent the part in the brake assembly from fusing. The first officer typically coordinates with airport traffic control to ensure airfield fire emergency services trail the aircraft and monitor the gear with thermal sensors. As the heat is dissipated from the assembly, the pilots continuously monitor the temperature gauges. It can take as long as 15 minutes for the heat level to climax after an RTO and begin dropping.

Most airlines establish a standardized waiting time on the ground before a second takeoff can be attempted if the plane is not mechanically at fault and an external cause forced the RTO. That is usually around one hour and requires inspection by the ground crew before a second take-off attempt can be made. If the temperature exceeds the tolerable range, then the flight crew will notify ground staff to stay clear of the aircraft and potentially cancel departure, then disembark passengers and cabin crew.

The Aftermath: Ground Support For A Hot Moment

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Following an RTO, the wheel well temperatures can be examined by the air control tower, ground staff, and airport fire teams using portable forward-looking infrared thermal cameras. Heavy-duty fans installed on the ground equipment can also be placed in front of the main landing gear assembly by ground maintenance crews if needed. To release the heat trapped in the brakes, these industrial blowers push high-velocity air straight into the wheel hubs. The ground staff may work with the pilot to use the aircraft’s internal electric brake fans as well, if available.

Before the aircraft is cleared for another flight, maintenance specialists must manually verify the thermal fuse plugs in each wheel. If the rejection occurred at high speeds, the plugs may have partially or completely melted, making it impossible to properly deflate the tires. External monitoring is essential because cockpit sensors might lag or malfunction under intense heat. Before taxiing, the ground crew must ensure that temperatures across all wheel assemblies have returned to the manufacturer’s permitted operating range.

The ground crew must tow the aircraft to a repair hangar to completely replace the damaged wheel and tire assemblies if any fuse plugs have activated. Because intense heat can result in pressure spikes that harm internal seals, technicians also employ gauges to verify the nitrogen pressure in unmelted tires. The braking stators and rotors may quickly wear out or deform due to the extreme friction of an RTO. To make sure there is enough material left for a later flight, ground crews measure the brake pins on each gear assembly. They do a thorough visual check for hydraulic fluid leaks as well.

Once the physical checks are completed and the brakes have cooled to normal operating temperatures, the ground crew signs off on the maintenance logbook. Technicians compare the aircraft’s onboard flight data recorder parameters to the manufacturer’s performance guides to ensure that the landing gear never exceeds ultimate structural heat limitations. Only after signing the formal engineering release will the flight crew be able to legally taxi back out to the runway for a second takeoff attempt.

Safety Starts At The Gate: Training For Every Possibility

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Pilots execute RTOs during each mandated recurrent simulator training cycle, which is commonly required about every six months. Instructors configure the flight simulator to cause catastrophic failures at the worst possible time, often one to two knots before V1 speed. This training emphasizes muscle memory and procedural adherence over diagnosis. Pilots are trained to automatically abort for high-speed criteria without having to glance at secondary instruments.

Verbal reinforcement of the Go/No-Go criterion is an important part of the briefing. In both the low-speed and high-speed regimes, the flying pilot will specify the precise circumstances that call for an abort. Before the airplane pushes back from the gate or takes off, a special threat and error management briefing is required for each flight departure. This briefing is led by the flying pilot, who vocally establishes the precise criteria for the impending takeoff. The particular aircraft weight, the length of the runway, and the day’s weather all affect this information.

The shift that takes place precisely at V1 speed is the last tactical measure in the briefing. While the captain maintains a tight grip on the thrust levers, the pilot monitoring is trained to place their hand close to the landing gear lever as the speed increases. When the airplane hits decision speed, the pilot monitoring loudly announces “V1.” The captain instantly takes their hand off the thrust levers and places it on the control yoke at this exact cue.