Landing Distance Required
Understanding landing distance required is vital for safe landings, especially when operating into short, wet, or contaminated runways. It ensures pilots can make informed decisions about runway suitability and aircraft performance, directly impacting flight safety.
Landing distance required is the minimum runway length needed for an aircraft to safely land and come to a complete stop, factoring in regulatory safety margins and real-world conditions. This calculation is crucial for dispatch, approach planning, and ensuring compliance with performance regulations for both dry and adverse runway conditions.
Quick Check
An aeroplane's baseline landing distance from 50 ft is 1400 ft. The runway is 2% downhill, grass, and wet. What is the required landing distance for commercial air transport after applying all corrections and the regulatory factor (1.43)?
Go beyond the textbook.
Explanation
What is Landing Distance Required?
Landing distance required (LDR) refers to the minimum runway length an aircraft needs to land from a specified screen height (usually 50 ft) and come to a full stop, considering aircraft performance, regulatory safety factors, and environmental corrections. It is a cornerstone of landing performance calculations and is essential for safe flight operations.
Landing Distance Calculation Steps
- Obtain Baseline Landing Distance: Use manufacturer data or performance charts to find the basic landing distance from 50 ft above the runway threshold under standard conditions.
- Apply Environmental and Surface Corrections: Adjust for runway slope (typically +5% per 1% downslope), surface type (e.g., grass, wet, contaminated), and wind (only a portion of headwind or tailwind is considered).
- Apply Regulatory Factors: For commercial operations, apply a safety factor—1.43 for turboprops (70% of LDA) and 1.67 for jets (60% of LDA). Multiply the corrected landing distance by these factors to get the required landing distance for dispatch.
- Cumulative Corrections: All corrections (slope, surface, wet/contaminated, regulatory) are multiplicative and must be applied sequentially.
Landing Distance Available (LDA) vs. Required
- LDA is the runway length declared usable for landing.
- LDR is the minimum LDA needed after all corrections and safety factors are applied.
Field Length Requirements
- Dry Runways: Use standard regulatory factors.
- Wet/Contaminated Runways: Apply additional correction factors (e.g., 1.15 for wet) before the regulatory factor.
Airborne vs. Ground Roll
- Airborne Distance: From 50 ft to touchdown.
- Ground Roll: From touchdown to full stop. Being too fast or too high at the screen height increases both airborne and ground roll distances, significantly lengthening the total landing distance required.
Practical Example
Given a baseline landing distance, corrections for a 1% downslope (+5%), grass (×1.15), wet surface (×1.15), and the regulatory factor (×1.43 for turboprops) are applied in sequence to determine the final LDR.
Key Points
Exam Traps & Typical Mistakes
Example Exam Questions
For a turbojet aircraft, which regulatory factor is applied to the actual landing distance to determine the minimum required Landing Distance Available (LDA)?
A turboprop aircraft has a calculated landing distance of 1200 m on a dry, paved runway. What is the minimum LDA required for commercial operations?
Still not fully confident?
Deepen your knowledge with an AI tutor built specifically for EASA ATPL students.
Built from thousands of ATPL knowledge references, real exam references and official learning objectives.
Open Avi AI TutorRelated Concepts
Still have questions?
Ask questions in plain English and get exam-focused explanations from an AI tutor built specifically for EASA ATPL students.
Open Avi AI