Numerical and Analytical Takeoff Field Length Calculations for Jet Aircraft

Bachelro Thesis

Autor: Dennis Lucht

Date: 2022-06-15

Supervisor: Dieter Scholz


Purpose – The greater of two distances (Balanced Field Length or Takeoff Distance +15%) results in the Takeoff Field Length (TOFL). The TOFL is a takeoff distance with safety margins according to Certification Standards for Large Aeroplanes by EASA (CS-25) and FAA (FAR Part 25). Simple analytical approximations for the TOFL are checked against more demanding numerical simulations to determine the validity of the simple solutions and to implement adjustments for them as necessary. The analyses are focused exclusively on jet aircraft with two and four engines. --- Methodology – The differential equation of the aircraft's acceleration is solved in MATLAB together with varying engine failure speeds. Analytical calculations of the Balanced Field Length by Torenbeek, Kundu, and Loftin are investigated. This includes the evaluation of statistical data. --- Findings – Analytical approximations deviate by 0.1% to 28.2% from the numerical solution. The most accurate analytical approximation is the simple method proposed by Loftin based on statistics. It shows deviations of less than 5.4%. The results confirm that the TOFL for jets with four engines is determined by the Takeoff Distance +15%, while for jets with two engines, the Balanced Field Length is decisive for TOFL. --- Research limitations – Simplifying assumptions had to be made e.g. regarding rotation time and speed, flap geometry, and asymmetric drag. While ground distances were solved numerically from acceleration and deceleration, air distance and rotation distance had to be determined analytically. --- Practical implications – A reliable and tested analytical procedure is useful for quick aircraft performance estimates and to include an inverse TOFL method into aircraft preliminary sizing. --- Originality – This seems to be the first report to provide a systematic check of available analytical approximations for the TOFL in comparison with a numerical solution. Purpose – This project investigates social impacts of aircraft with a life-cycle approach using the example of the Airbus A380 program. --- Methodology – Social impacts are analyzed by conducting a Social Life Cycle Assessment (S-LCA) based on the "Guidelines for Social Life Cycle Assessment for Products" from the United Nations Environment Programme (UNEP) and the Society of Environmental Toxicology and Chemistry (SETAC). Stakeholder and subcategories are chosen, and data is collected by conducting qualitative interviews and web searches. An impact assessment is performed using the Subcategory Assessment Method (SAM). The results are interpreted and generalized. --- Findings – During its life span, an aircraft or aircraft program has an impact on different stakeholders. The life cycle stage "raw material extraction" could lead to human rights violations, but also local communities near main manufacturing sites face social implications, both positive and negative. The economic importance of the aeronautic sector influences society, political decision makers, local communities, and workers. All this was evident also in the A380 program. --- Research Limitations – Data availability limited the investigation partially. The project does not cover all life cycle stages and stakeholder groups. Instead, emphasis is given to selected stages and groups. --- Practical Implications – The study can help aviation decision makers to provide a product, which improves the well-being of its stakeholders. --- Social Implications – Performing an S-LCA in aviation puts social implications of the aircraft program into focus and provides a foundation for a general discussion about its social sustainability. --- Originality – This seems to be the first research on the topic of S-LCA of an aircraft or aircraft program.

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PURL, the Persistent Identifier to quote this Landing Page: https://purl.org/HAW/BA2022-06-15 pin

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Associated research data: https://doi.org/10.7910/DVN/QX3MAH

Triebwerke und Wirkungsgrade: Formeln

Balanced Field Length (BFL) and Take-Off Distance (TOD) with All Engines Operative (AEO) factored with 1.15 to give TOD1.15 . Aircraft with 2 engines are sized from BFL. Aircraft with 4 engines are sized from TOD1.15 .



Modified analytical solution from Loftin to estimate Take-Off Field Length (TOFL).

LAST UPDATE:  03 April 2023
AUTHOR:  Prof. Dr. Scholz

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