The economic situation of recent years forces to operate at highest payloads possible and therefore maximum allowable take-off masses of an aircraft. An optimization of the take-off performance plays important role as never before. The take-off performance data for several flight and ambient conditions are usually presented in so called runway analyses. This paper answers possible questions about their application and computing, which may interest a personnel of flight engineering departments or pilots. Moreover, this thesis offers a summary of factors affecting the maximum take-off mass and appropriate take-off speeds, which together represent necessary performance data for a safe take-off. Particular sections describe a principle of the optimization process and offer a designed conceptual model in a form of flowcharts according to which it is possible to perform a calculation for various aerodrome or weather conditions. The created conceptual model may also serve as a core for the software application, which reduces the time required to do the calculation manually.
Table of Contents
1 DEFINITION AND PURPOSE OF RUNWAY ANALYSIS
2 FACTORS AFFECTING MTOM AND V-SPEEDS
2.1 MSTOM
2.2 THE AERODROME RUNWAY DISTANCES
2.2.1 Line-up distance
2.2.2 Take-off Distance
2.2.3 Take-off Run
2.2.4 Accelerate-stop Distance
2.3 CLIMB LIMITATIONS
2.4 OBSTACLE CLEARANCE
2.4.1 Vertical plane
2.4.2 Horizontal plane
2.5 METEOROLOGICAL ELEMENTS
2.5.1 Wind
2.5.2 Pressure altitude
2.5.3 Temperature
2.6 RUNWAY SLOPE
2.7 RUNWAY CONDITION AND CONTAMINATION
2.7.1 Definitions
2.7.2 Effect on aircraft performance
2.8 TIRE SPEED LIMIT
2.9 BRAKE ENERGY CAPACITY
2.10 AIRCRAFT CONFIGURATION AND SYSTEMS SETTING
2.11 AIRCRAFT STATUS
2.12 BEARING STRENGTH
3 TAKE-OFF DATA OPTIMIZATION PRINCIPLE
3.1 AIRCRAFT CONFIGURATION AND SYSTEMS SETTING
3.2 V1/VR RATIO
3.2.1 v1/vr range
3.2.2 v1/vr ratio influence
3.3 V2/VSR RATIO
3.3.1 v2/vSR range
3.3.2 v2/vSR ratio influence
3.4 TAKE-OFF DATA DETERMINATION
3.4.1 MTOM
3.4.2 v-speeds
4 EXISTING RUNWAY ANALYSES PRODUCTS
4.1 AIRCRAFT MANUFACTURER SOFTWARE
4.2 APG
4.3 FLYGPRESTANDA
4.4 ASAP
4.5 HONEYWELL
4.6 EFRAS
4.7 CONCLUSION OF RUNWAY ANALYSES REVIEW
5 RUNWAY ANALYSIS CONCEPTUAL MODEL FOR TAKE-OFF
5.1 INPUT DATA
5.2 MASS TO V1/VR RATIO GRAPH
5.3 OPTIMIZATION PROCESS
5.4 V-SPEEDS EVALUATION
Objective and Key Themes
The primary objective of this thesis is to analyze the critical factors influencing aircraft performance during take-off, to define an optimization principle, and to propose a systematic calculation method for determining the maximum operationally allowable take-off mass in compliance with current European Union aviation regulations.
- Analysis of factors affecting Maximum Take-off Mass (MTOM) and V-speeds.
- Evaluation of runway performance limitations including climb gradients and obstacle clearance.
- Development of a conceptual model and flowcharts for take-off data optimization.
- Comparative review of existing commercial runway analysis software products.
- Integration of meteorological and aerodynamic variables into take-off performance calculations.
Excerpt from the book
2.2.1 Line-up distance
Prior to the take-off it is necessary to align the aircraft with runway heading in a direction of intended departure. To utilize all runway length it is favorable to do so at the very beginning of the runway surface dedicated for the take-off. At most aerodromes turns on the runway are required and therefore any time the access to the runway does not permit positioning of the aircraft at the threshold, the line-up corrections are necessary to consider. The alignment distance depends on the aircraft geometry and the access possibility to the runway in use. Usually, it is required 90° turn in order to enter the runway from a taxiway or 180° turnaround on the runway. Typically, the minimum line-up distance is provided by an aircraft manufacturer, but in case of 180° turnaround the minimal runway width, required for performing such turn, has to be additionally considered.
Consequently, the aircraft line-up distance at a particular aerodrome negatively influences the distances of TODA, TORA and ASDA. The reduction of these distances however differs for TODA and TORA on one side and for ASDA on the other. The TODA and TORA adjustments are based on initial distance of the main gear from the beginning of the runway since the screen height is measured from the main gear. On the other hand, adjustment of the ASDA is established upon a distance from the beginning of the runway to the nose gear.
Summary of Chapters
1 DEFINITION AND PURPOSE OF RUNWAY ANALYSIS: Describes the fundamental responsibility of operators to ensure safety through pre-flight performance calculations and the role of runway analysis in determining maximum allowable take-off and landing masses.
2 FACTORS AFFECTING MTOM AND V-SPEEDS: Provides a comprehensive overview of the technical parameters that influence aircraft take-off performance, including runway geometry, meteorological conditions, and structural limits.
3 TAKE-OFF DATA OPTIMIZATION PRINCIPLE: Explains the iterative process required to balance "sustained" fixed parameters with "free" configuration variables to achieve the highest possible take-off mass.
4 EXISTING RUNWAY ANALYSES PRODUCTS: Reviews several commercial software solutions used by airlines to manage take-off data, comparing their layouts, usability, and methodologies.
5 RUNWAY ANALYSIS CONCEPTUAL MODEL FOR TAKE-OFF: Introduces a standardized calculation method using flowcharts to enable flight engineering departments to perform accurate performance assessments independently of specialized third-party tools.
Keywords
Runway analysis, Aircraft performance, Maximum take-off mass, V-speeds, Take-off optimization, Climb limitations, Obstacle clearance, Meteorological elements, Accelerate-stop distance, Flight engineering, European Aviation Safety Agency, CS-25 regulations, Take-off configuration, Airframe performance, Performance class A
Frequently Asked Questions
What is the core focus of this research?
The research focuses on the optimization of aircraft take-off performance and the determination of the maximum operationally allowable take-off mass (MTOM) for large commercial aeroplanes under EASA regulations.
Which specific aircraft are covered in this study?
The study covers large commercial airplanes assigned to performance class A, including multi-engine turbo-propeller aircraft exceeding 5,700 kg or seating more than 9 passengers, and all multi-engine turbojet aircraft.
What is the main goal of the proposed calculation method?
The goal is to provide a reliable, step-by-step conceptual model using flowcharts that allows operators to independently calculate optimized take-off data when external software might be unavailable or for specific abnormal conditions.
Which scientific methodology is applied here?
The work uses an analytical approach, reviewing existing regulatory standards (such as CS-25 and EU-OPS) and applying aerodynamic physics and aircraft performance engineering to create a structured decision-making model.
What topics are discussed in the main body of the thesis?
The body covers factors influencing MTOM and V-speeds (runway distances, meteorology, obstacle clearance), the principles of optimization, a review of software products like EFRAS and OCTOPUS, and a final conceptual model for manual or software-integrated calculation.
How would you describe the key themes of this work?
Key themes include safety-critical performance limits, economic optimization in airline operations, regulatory compliance, the transition to 'less paper' cockpits, and the mathematical determination of V-speeds based on environmental and physical constraints.
Why is the "line-up distance" important for performance calculation?
The line-up distance is crucial because it reduces the available runway length (TODA, TORA, ASDA) depending on where the aircraft enters the runway, which directly impacts the calculated MTOM.
How do contaminants like slush or standing water affect performance?
Contaminants introduce significant drag and risk of aquaplaning, which degrades acceleration and braking performance, necessitating specific adjustments to take-off distances and screen heights as outlined in the aircraft flight manual.
What role does the V1/VR ratio play in the optimization process?
The V1/VR ratio is a key free parameter. Increasing it can improve certain performance aspects but may make other limitations, such as brake energy capacity during a rejected take-off, more restrictive.
- Quote paper
- Boris Urbanek (Author), 2012, Safe take-off with runway analyses, Munich, GRIN Verlag, https://www.grin.com/document/195384
