In aviation, a hard landing refers to the type of landing where an aircraft touches the runway with a higher vertical speed than normal. This can lead to higher loads on the aircraft fuselage, landing gear, and structural components compared to a standard landing. A hard landing can occur due to pilot error, adverse weather conditions, incorrect approach angle, or technical malfunctions.

^{Examples of Aircraft Performing Hard Landings (Most Dangerous)}

Technical Specifications and Evaluation Criteria for Hard Landings

In aviation, a "hard landing" refers to a situation where an aircraft touches the runway with a vertical acceleration or vertical speed exceeding the structural limits defined by the manufacturer during landing. Since this situation can cause structural stress on the aircraft, it is defined by specific technical criteria and requires post-landing inspection procedures.

Civil aviation authorities and aircraft manufacturers define hard landings with technical limits. For instance, if the vertical acceleration (g-force) recorded on the aircraft during flight exceeds a certain threshold value, it is considered an indicator of a hard landing. Typical threshold values vary by aircraft type; for example, they are approximately 2.6 g for Airbus A320 type aircraft, 2.2 g for Boeing 737, and 1.8 g for Boeing 747. These data are detected via Flight Data Recorders (FDR) and must be considered along with pilot reports and technical investigations for reliable evaluation.

Another technical indicator of a hard landing is the vertical speed during landing. Generally, descent rates above 600 feet/minute (approximately 3 m/s) can be considered a hard landing, especially when appropriate runway conditions are not met. However, vertical speed alone is not the sole determinant; the aircraft's weight at touchdown, flap configuration, and runway condition must also be taken into account.

Following a hard landing, structural checks must be performed within the scope specified in the aircraft manufacturer's maintenance documentation. These checks are applied against the risk of damage to all components that could affect flight safety, particularly the landing gear and fuselage. For the aircraft to be returned to service, these checks must be completed in accordance with the criteria set by the manufacturer.

Causes

Hard landings can occur as a result of the interaction of multiple factors. These factors range from flight conditions to technical malfunctions. The primary prominent causes include:

• Meteorological Conditions: Weather factors such as wind shear, turbulence, and slippery runway surfaces can make a safe landing difficult for the aircraft.
• Pilot Errors: Human-induced factors such as high-speed approach, steep approach angle, and braking errors can lead to a hard landing.
• Technical Malfunctions: Technical problems such as errors in the auto-landing system or flap malfunctions can threaten flight safety during landing.
• Weight and Balance Problems: Issues with the aircraft's center of gravity distribution can negatively affect flight dynamics, causing a hard landing.

Consequences and Risks

A hard landing imposes a high level of stress on the aircraft fuselage and structural components, leading to both short-term and long-term operational risks. The consequences of such landings are not limited to physical damage; they directly affect maintenance processes, flight safety, and operational continuity. Below, the main consequences and risks of a hard landing are explained:

Risk of Structural Damage

High vertical forces during a hard landing can lead to micro-cracks or deformations in the main structural elements of the aircraft (e.g., fuselage frames, connection points, landing gear bays). These damages may not be visible at first glance; however, since they can cause fatigue-induced fractures over time, they must be detected using special inspection methods.

Landing Gear Malfunctions

Landing gear are among the most critical components directly affected by a hard landing. Excessive loading can cause damage to landing gear shock absorbers, connection points, or the landing gear actuation systems. Such damage can seriously jeopardize safety during subsequent landings and takeoffs.

Fuselage Cracks and Surface Stresses

Hard landings can lead to crack formation on the fuselage surface or in connection areas. Especially wing-root junctions and the tail section are at high risk as they are load transfer points. If such cracks are not detected in time, they can threaten the integrity of the fuselage in the long term.

Risk of Runway Excursion and Overrun

A hard landing, particularly when it occurs on short runways or in wet/poor-surface runway conditions, can cause the aircraft to lose control on the runway. This situation can result in events such as a runway excursion or overrun.

Operational Safety and Maintenance Process

Following a hard landing, the aircraft must undergo a detailed technical inspection. According to the "hard landing inspection protocol" included in the aircraft manufacturer's maintenance procedures; comprehensive checks must be performed on the landing gear, fuselage, and critical systems, and NDT (Non-Destructive Testing) methods should be applied if necessary. Without completing this maintenance process, returning the aircraft to service poses a serious risk to flight safety.

Related Procedures

The International Civil Aviation Organization (ICAO) and airline maintenance regulations stipulate that special procedures be applied to the aircraft's maintenance records and structural checks performed in the event of a hard landing. Additionally, the flight crew must note and report the incident in the flight recording system (Flight Data Recorder).