A ticket for speeding while driving a car is a black mark and can lead to all sorts of problems. But what happens when the flight crew exceeds a flight’s speed limit? And can a pilot receive a ‘speeding ticket’?
How is an aircraft’s speed different from a car’s speed?
Unlike driving a car, assessing how fast an aircraft is traveling is more complicated. The speed of an aircraft depends on various factors, including atmospheric environment, pressure, altitude, temperature, the weight of the plane, and the freight it carries.
So, how is aircraft speed typically measured?
It is common to express aircraft speed in terms of knots (kn) or nautical miles per hour, but it could also be expressed by miles per hour (mph).
Various types of airspeed exist, which are measured during different phases of flight.
Groundspeed (GS)
When a plane is still on the ground, a groundspeed (GS) is commonly used to describe how fast it is moving horizontally. It describes the speed at which the plane moves relative to a fixed point on the ground. GS is measured by a groundspeed radar and is usually part of the aircraft’s GPS systems.
Even though groundspeed plays a vital role in precise aircraft navigation, it can be significantly impacted by the surrounding wind, which can push the aircraft along at a faster speed. For instance, if a jet needs to develop 140 knots groundspeed for taking off but faces a headwind of 20 knots, it means that the flight crew will only need to reach 120 knots groundspeed before the plane will be able to take off.
Meanwhile, when the aircraft faces a tailwind of 20 knots, it means that pilots will need to develop a 160-knot groundspeed to be able to move the jet off the ground.
True airspeed (TAS)
True airspeed (TAS) is another type of aircraft speed. It shows how fast a plane moves through the air in which it is flying by reflecting calculations of the jet’s altitude and the airmass.
A pilot is obliged to include TAS when filling in a flight plan and inform air traffic control (ATC) if the index changes during the flight. This allows the traffic controller to adjust to the aircraft’s flight path and warn the flight crew about potentially risky weather conditions.
Indicated airspeed (IAS)
Indicated airspeed (IAS) shows how fast the airspeed indicator thinks that the jet is moving through the air. IAS is based on the air data computer which converts the ram air pressure received at the pitot tube into an index on the instrument in the flightdeck. By following IAS changes mid-flight, the pilots can prevent a sudden reduction in the lift when the aircraft reaches or exceeds a critical angle of attack.
The aircraft speed limits in the sky are expressed as indicated airspeed values.
How fast is too fast for an airplane?
The higher the plane flies, the higher speed it can develop. Whether it is a commercial airliner, a private jet, or a single-engine small plane, the speed the aircraft is capable of reaching depends on its engine type, takeoff weight, and aerodynamic properties.
A commercial passenger plane usually reaches a cruise speed of between 400 and 500 knots (460-575 mph) at an altitude of 36,000 ft. For instance, a Boeing 747 ‘Queen of the Skies’ cruises at a speed of around 570 mph, while its rival Airbus A380 ‘superjumbo’ is capable of cruising at a speed of 561 mph. The fastest commercial aircraft to date was the tailless narrow fuselage supersonic airliner Concorde, which was able to reach speeds greater than 1,300 mph.
In comparison, the average private jet develops an average cruise speed varying between 400 and 600 mph. For example, the Gulfstream G700 develops a cruise speed of up to 740 mph.
But what happens if an aircraft flies too fast?
The airframe then experiences a condition in which the jet engine operates beyond the design limit set by the manufacturer, which is known as overspeeding. While in jet aircraft overspeeding occurs when the axial compressor exceeds its peak operating rotational speed, in a turboprop such a condition results when a high-speed airflow makes a propeller, which is directly connected to the engine, operate too fast.
Subject to the duration of running the engine and the speed reached, overspeeding commonly leads to a harshly reduced engine life, a mechanical turbine blade failure, a flameout, or even structural damage to the entire engine.
Therefore, the pilot must follow IAS speed limits indicated in the airline’s manuals, based on the manufacturer’s guidelines.
Why do airplanes not fly at the highest possible speeds?
Commercial passenger aircraft rarely operate at their maximum speed. Like a car, this is down to peak fuel efficiency.
From the perspective of fuel consumption, there is an optimal cruising speed based on altitude the aircraft is flying. It usually varies between 475 and 500 kn (547-575 mph) while operating at altitude of between 31,000 and 38,000 feet, according to the FAA.
Flying at higher speeds could cut the duration of the flight, but this would significantly increase fuel expenses, according to Airbus. Therefore, airlines maintain the recommended speed limit as a cost-saving measure.
But there’s another reason why airplanes do not fly at their highest speeds. As going faster requires an aircraft engine to generate more power, airlines usually prefer operating at lower speeds rather than hitting the maximum to make an engine and other related parts last longer.
However, when it comes to private jets, they often fly faster than commercial planes due to the way they are built and the lack of requirement to save money.
Speed limits in the sky
Speed limits do apply. Such limits are enforced for the prevention of potential hazards, including bird strikes or if an aircraft is too close to another plane.
For instance, according to the Codel of Federal Regulations, particularly FAR 91.117, it is forbidden in the United States to fly any plane below at an altitude of 10,000 feet at an indicated airspeed of more than 250 knots or 288 mph. There are some other speed limits for holds depending on the altitude at which the plane is flying as well as for arrival procedures, which vary from one airport to another.
The European Aviation Safety Agency (EASA) maintains similar speed restrictions in Europe, which vary depending on airspace classification.
Can pilots be penalized for flying too fast?
The golden rule that every pilot follows is this: if the air traffic controller has issued a speed restriction while vectoring a plane, it will continue to apply when an altitude change is made.
However, it remains the flight crew’s responsibility to make speed adjustments to maintain proper speed and ensure aircraft safety.
So, what would happen if a pilot exceeded the allowed maximum aircraft speed and did not maintain a certain speed as per the ATC request?
A pilot would not get pulled over, of course. But speeding is considered a serious violation of aviation regulations (unless there’s an emergency in-flight).
Since the ATC is responsible for observing a plane’s movement, controllers can issue a pilot deviation if pilots do not follow the control tower’s warnings. A pilot deviation record could be made when the flight crew strays from an assigned heading, altitude, or instrument procedure or if pilots penetrate controlled or restricted airspace without ATC clearance.
The deviations can also occur on the ground during aircraft taxiing, taking off, or landing without clearance, deviating from an assigned taxi route, or failing to hold short of an assigned clearance limit.
Unlike driving a car, a “speeding ticket” will not be issued for a pilot in an event of exceeding the assigned aircraft speed and it is a rare practice for aviation authorities in the US or Europe to apply financial penalties for a pilot individually.
For example, in the US, the FAA Enforcement Division may initiate a civil penalty action in some cases, and this can result in a penalty ranging between $1,100 to $27,500. But it is not a common consequence in the event of ‘speeding’.
Most often, depending on the airspace where the violation of the ATC requirements was recorded, a pilot’s actions can become subject to a detailed FAA, EASA or national authority investigation. Generally, it could lead to a pilot certificate suspension and even licence revocation.
So, can a pilot receive a ‘speeding’ ticket for flying too fast? Unlikely. But there is a high likelihood of losing the opportunity to hold aircraft controls ever again.