Overshoot – Landing Beyond the Intended Touchdown Point

Definition: Overshoot in Aviation Operations

Overshoot in aviation is a critical safety term describing a landing in which the aircraft’s wheels first contact the runway beyond the designated touchdown zone (TDZ). The TDZ is the only part of the runway where safe, performance-assured landings are intended, as defined by ICAO Annex 14 and FAA AC 91-79A. Touching down past this zone immediately reduces available runway for stopping, greatly increasing the risk of runway excursions and overruns. Overshoots are a leading precursor to runway overrun accidents and are universally considered a preventable operational hazard.

Standard Touchdown Zone (TDZ) and Operational Parameters

The Touchdown Zone (TDZ) is defined as the first 1,000 feet (300 meters) or the first third of the runway, whichever is less. Marked by prominent white “aiming point” rectangles and pairs of white bars, the TDZ is the reference for both pilots and performance calculations.

• Aiming Point vs. Touchdown Point: The aiming point is a visual marker for pilots to use during approach. Actual wheel contact (touchdown point) usually occurs slightly beyond this due to the flare maneuver. The goal is to land within the TDZ, not on the aiming point itself.
• Regulatory Basis: Aircraft manuals, SOPs, and regulations assume touchdown occurs inside the TDZ. If landing cannot be assured in this zone, a go-around is mandatory.

Causes and Contributing Factors to Overshoot

Overshoot risk stems from a combination of technical, operational, human, and environmental factors:

1. Excessive Approach Speed: Even small increases in speed cause excessive float and longer landing rolls. For example, a 10% speed increase raises landing distance by 20%.
2. Unstabilized Approach: Deviation from prescribed speed, descent rate, or alignment often results in late touchdowns.
3. Delayed/Improper Flare: Poor flare timing or technique can cause excessive float.
4. Tailwind Component: Tailwinds increase groundspeed and landing distance, with every 10 knots of tailwind adding approximately 21% to stopping distance.
5. Wet or Contaminated Runway: Water, ice, or snow sharply reduce braking effectiveness. Landing rolls can increase by 40% to over 200% on contaminated surfaces.
6. Aircraft Weight & Configuration: Heavier aircraft land faster and take longer to stop; improper configuration (flap, gear) compounds the risk.
7. Delayed/Improper Use of Deceleration Devices: Late deployment of brakes, spoilers, or thrust reversers adds hundreds of feet to the landing roll.
8. Human Factors: Fatigue, distraction, poor communication, and reluctance to go around.
9. Environmental/Runway Factors: High elevation, temperature, and slope can all increase required landing distance.

Overshoot incidents often involve several of these factors together, underscoring the importance of operational discipline.

Operational and Safety Implications of Overshoot

Landing beyond the TDZ critically reduces available runway for stopping, invalidating all published landing performance data and exponentially increasing risk:

• Available Stopping Distance: Overshoot directly subtracts from the available stopping distance, raising the likelihood of runway excursions.
• Runway Overrun Risk: Overshoot is a leading factor in global landing accidents, especially at airports with short or contaminated runways.
• Performance Data Invalidated: All certified landing data assume touchdown within the TDZ—overshoot voids these calculations.
• Potential Damage and Injury: Runway excursions often result in significant aircraft damage and can cause injuries or fatalities.
• Regulatory/Insurance Consequences: Many authorities require reporting of overshoot incidents, which may affect insurance coverage.

Strict adherence to stabilized approach and TDZ landing criteria is essential for safety.

Examples and Use Cases of Overshoot

• Commercial Example: A turboprop lands 1,700 feet past the threshold on a 5,000-foot runway due to excessive speed, resulting in an overrun.
• Case Study: Citation 550 overrun after late touchdown and delayed thrust reverser deployment; investigation highlighted operational errors with no mechanical faults.
• SOP/Training: Modern SOPs require a go-around if the aircraft floats beyond the TDZ.
• Short/Contaminated Runways: Even small overshoots can lead to runway excursions on short or slippery runways; pilots must brief and adhere to TDZ criteria.

Prevention and Mitigation Strategies

1. Stabilized Approach Criteria: Approaches must be stabilized by 1,000 ft AGL (IMC) or 500 ft AGL (VMC). Unstable approaches require an immediate go-around.
2. Correct Speed and Configuration: Strictly maintain calculated Vref and full landing configuration prior to the TDZ.
3. Accurate Aiming/Sight Picture: Use aiming point markings and recognize expected float from flare.
4. Timely Deceleration Device Use: Deploy spoilers, brakes, and thrust reversers immediately after touchdown.
5. Go-Around Readiness: Brief and execute go-arounds when TDZ landing cannot be assured—this is non-negotiable.
6. Performance Assessment: Pre-assess runway length, condition, and required margins.
7. SOP and Regulatory Compliance: Adhere to all procedures and regulations; regular training and checking reinforce these standards.

Related Terms and Explanations

Common Errors and Misconceptions

• Aiming Point vs. Touchdown: Aiming for the marking is not the goal; the touchdown point should be just beyond, within the TDZ.
• Floating Beyond TDZ: Excessive speed or poor flare leads to overshoot—never try to salvage such approaches.
• Delayed Go-Around: Once past the TDZ, a safe stop may not be possible.
• Ignoring Environmental Factors: Not accounting for wind, slope, or contamination skews performance calculations.
• Overreliance on Automation: Automation can mask unstable conditions; pilots must remain vigilant.

Aviation Operations Use Cases

• Flight Training: Instructors stress the dangers of overshoot, train for precise speed/flaring, and enforce go-around discipline.
• Crew Resource Management (CRM): Emphasizes communication and cross-checking for TDZ adherence.
• Safety Audits: Data on overshoot trends inform corrective actions and training.
• SOP/Checklist Development: Maximum touchdown points and go-around criteria are codified.
• Performance Calculations: Real-time runway condition assessments are used to adjust landing plans and margins.

Diagrams and Visual References

Effect of Contributing Factors on Landing Distance:

Multiple small errors can combine to quickly erode landing safety margins.

Key Points and Cautions

Key Point: Touching down beyond the TDZ invalidates all landing performance data and can result in insufficient stopping distance.

Caution: If you cannot assure touchdown within the TDZ, initiate a go-around—never attempt to salvage a long or unstable approach.

Sources:

• ICAO Annex 14, ICAO Doc 9870 (Manual on the Prevention of Runway Excursions)
• FAA Advisory Circulars (e.g., AC 91-79A)
• Flight Safety Foundation, ACRP Reports
• Aircraft Flight Manuals (AFM), Operator SOPs

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