Nasos Apostolopoulos

William Lamb

Prior to the integration of Geographic Information Systems into airport and runway analysis, such analyses were very laborious and time consuming. All obstacle source data come in different formats, thus each source had to be individually evaluated to determine the impact on aircraft performance. This evaluation involved painstaking manual measurements and plotting on paper. The process was repeated several times until every source had been evaluated. Thus, a system that could integrate multiple layers of source data and extract pertinent data was needed to automate the analysis procedure. The Pegasus GIS application provided the solution

Introduction

Jeppesen, a Denver-based, Boeing owned company, is recognized as the world's leading supplier of flight information, providing flight planning services, aviation weather services, maintenance information, and pilot training systems. The Jeppesen group of companies has offices in the United Kingdom, Germany, Australia, China, and other US locations.

For more than 20 years, Jeppesen’s Operations Data department (OpsData) has been a leading supplier of aircraft performance information and airport analysis services worldwide. OpsData provides aircraft operators the information required to comply with regulatory requirements for engine-out performance. Airport analyses consist of computerized computations of maximum allowable takeoff and landing weights for a range of temperatures. These calculations are customized for a particular aircraft/engine configuration for a specific runway at a given airport. The computation considers various aircraft characteristics such as flap settings, runway conditions, obstacle clearance and winds. OpsData maintains a worldwide database of more than 15,000 runways of these computations.

Flight safety is indisputably one of the biggest concerns to the aviation industry. The financial well being of airlines is directly influenced by their safety record. It should therefore come as no surprise that airlines are taking extraordinary precautions to meet flight safety standards. The standards in the U.S. are dictated and enforced by the Federal Aviation Administration (FAA). In areas outside the USA international organizations such as ICAO are responsible for the development of these standards. Among all airline accidents, terrain collisions during takeoff or landing account for 62% of them. The position and altitude of the aircraft in relation to the terrain is critical information to the pilot.

In 1997, Jeppesen initiated the development of a GIS-based application that allows automated analysis of "surface features" (terrain and human-made structures) as they relate to the position of an aircraft. This system has been named "Pegasus".

Pegasus was developed for the purpose of automating airport analysis. Airport analysis is the process of evaluating the airport takeoff environment for obstacles of any nature and calculating the maximum takeoff weight for a flight. An aircraft experiencing an engine loss on takeoff can potentially lose 70% of its climb performance. The determination of aircraft weights ensures clearance from all terrain and man-made obstacles in the case of an engine-out emergency at the most critical point during take-off. These analyses also provides regulatory compliance pertaining to aircraft take-off and landing calculations.

The standard Airport Analysis considers obstacles along a straight-out flight path. If a straight-out departure is not practical or recommended, OpsData designs a turn procedure in order to maximize the allowable takeoff weights and ultimately, increase payload. An increased payload allows airlines to operate longer routes carrying more passengers and cargo.

In the past, in order to ensure obstacle clearance, Jeppesen had to manually perform a detailed obstacle analysis for the engine-out departures for every runway at a given airport. These calculations often took several days. Runway analysis was a very laborious and time-consuming task, as obstacle source data comes in multiple, disparate formats. Each source had to be individually evaluated to determine the impact on aircraft performance. This evaluation involved painstaking manual measurements and plotting on paper. The process was repeated several times until every source had been evaluated. Verification of the hand plotting and measurements compounded the problem by introducing another bottleneck in the analysis cycle. To analyze the terrain and obstacles for a given runway, the analyst had to "zoom-out" of the airport environment progressively evaluating charts of smaller scale. Jeppesen needed a system that could integrate multiple layers of source data and extract pertinent data as needed to automate OpsData production.

By utilizing the geometric constructs available in Esri’s ArcView GIS, Jeppesen is now able to perform that analysis in minutes! The Pegasus system was constructed with ArcView GIS, Spatial Analyst, and ArcINFO. Now digital terrain, obstacle, airport, navigation, and cultural data can be seamlessly integrated to analyze departure tracks in accordance with applicable aviation regulatory requirements.

The minimum system requirements for the Pegasus client are a standard Windows NT workstation, with 700 MHz CPU, a 10 GB hard drive, 128 MB RAM, 1280 x 1024 screen setting, and a 19" or 21" monitor, and a network card. Esri client software (Arc/View) is also required. The minimum requirements for the Pegasus server include an UNIX or NT Server, with 700 MHz CPU, 512 MB of RAM, and around 10-20 GB disk drive. Esri server software (ARC/INFO) and Sybase or Oracle for database storage are required.

Pegasus greatly reduces the time it takes to analyze runway takeoff paths. It allows accurate analysis of aeronautical, terrain and obstacle data by collecting and integrating data in one centralized place. It enables customization of the airport analysis product by means of tailoring and optimizing special engine-out procedures for specific aircraft.

Included in the Pegasus system are interfaces that help Jeppesen manage and visualize raster and vector data by providing display, analysis, change management, and edit modules that can access a centralized data warehouse over a wide area network.

The display module allows a user to retrieve previously stored airport analyses and aircraft departure procedures for display in ArcView GIS. Here, tools are provided to allow the production of tabular reports and layouts. The analysis module has tools that assist the user in creating custom or standard aircraft departure procedures using navigational aids and visual terrain verification. Once such a procedure is constructed, the user can analyze all obstacles in that flight path. This allows Jeppesen to identify and avoid critical obstacles and noise-sensitive areas, increase maximum takeoff weights, and integrate engine-out procedures into the analysis.

The change management module provides tools that allow the user to compare all previously stored procedures against any changes in the obstacle database, and produce a report of those procedures possibly affected. The edit module contains tools that allow the user to add, delete, or modify any polygon, polyline, and point features in the data warehouse.

The user enters the system through a dialogue box by requesting the airport location.

Pegasus returns with a 40-mile radius from the requested airport/point, and displays all available coverages of surface features (Terrain, Obstacle data from source A,B,C....). Human created obstacles carry a Mean Sea Level (MSL) elevation figure while raster terrain is color-shaded appropriately. Detailed data on individual obstacles and other features, can be readily obtained through the use of an "ident" tool. Contours can be generated from the terrain grid to enhance visibility and decision making. A simplified airport diagram is also shown on the screen. The analyst selects the runway to be analyzed and the appropriate regulatory environment rules.

Depending in the magnitude of the surface features that the aircraft need to clear on takeoff, the analyst is able to perform either a straight out or "obstacle avoidance" escape turn analysis.

The takeoff speed of an aircraft determines the performance operating environment. A larger, heavier jet generally flies faster than a smaller lighter one. Consequently, the heavier jet has a larger turn radius which results in covering a wider area on the ground while turning. The obstruction differences associated with variations in the turning radius can be significant between different aircraft types. Pegasus allows for the selection of the appropriate performance operating environment.

With the integration of GIS into their operations, Jeppesen was able to increase productivity by 400% due to the reduction of time it takes to analyze take-off paths. Accurate and precise analysis of aeronautical, geographic (terrain) and obstacle data is mission critical; so Jeppesen is constructing a central repository of worldwide Geo-Spatial Information that will be able to meet the present and emerging demands for Airport GIS, Airport and Runway Procedure Analysis, and Enroute and Terminal Terrain Avoidance.