Research Projects

Effective practices for monitoring and managing tree growth off the airport. In Reserve

Conduct research into cost effective strategies for periodic monitoring of airspace surfaces such as TERPS 20:1 surfaces to ensure they remain clear of obstructions. Particularly at smaller rural airports that may not have staff, zoning, or significant infrastructure that would otherwise make these issues easier to manage.

Background (Describe the current situation or problem in the industry, and how your idea would address it.)

Tree growth in non-urban environments can penetrate airspace surfaces such as TERPS 20:1 visual segment. Review the situation that occurred in Saratoga Springs, NY in 2008 where a learjet struck a tree while flying the approach. The reality is that tree growth off airport property over a time of many years can create obstructions in areas that are required to be clear and if there has not been a recent survey those obstructions could go unidentified for years and plausibly could cause an accident resulting in airport liability exposure.

This issue is perhaps more pressing at smaller airports in rural settings; airports with limited or no specialized staff that not that long ago did not have instrument approaches due to the amount of ground based infrastructure required. Prior to GPS approaches becoming a reality these airports were often VFR only airports and tree growth outside of the immediate runway environment was not a major issue. Fast forward to today and GPS approaches are extremely common in the NAS and many airports that never had instrument approaches before have them today. Many of these airports were never designed or planned for the instrument approaches that they have today. Property boundaries, zoning and many other issues may not be optimal at these airports for controlling obstructions to the much more stringent instrument approach standards.

Aeronautical surveys or surveys used by FAA to create new approaches can identify these obstructions, however these surveys only represent a snapshot and a new survey may be more than a decade away or longer. While Part 77 requirements, zoning, and other restrictions may ensure vertical development like structures and towers are analyzed there is no regulation effective at preventing trees from growing. Airports need methodologies, tools, and strategies to periodically monitor these areas that are less costly than repetitive formal surveys. This research would examine a multitude of methods and strategies for monitoring tree growth into protected airspace surfaces.

Objective (What is the desired product or result that will help the airport industry?)

Objective analysis of various methods for airports to monitor tree growth at lower costs than formal surveys. Analysis should include effectiveness, accuracy, ease of use, costs including acquisition and maintenance/subscription costs, life cycle issues, level of training or expertise required to perform the assessment, and ability to translate findings into actionable data in the field to remove identified obstructions. Possible concepts might be drone collected LIDAR or photogrammetry, visual assessment with various consumer/prosumer level instruments, available systems or technologies specifically targeted at airport obstruction analysis, and even one time use strategies. An example of a one time use strategy could be an analysis and review of existing or new data at an airport that is then used to establish various geographic zone boundaries and not to exceed heights along with maintenance schedules and height limits for each zone. This final concept could result in a simple map, GPS coordinates, location stakes in the field, and depending on the area could feature monthly, yearly, or longer term clearing cycles and standards that would ensure vegetation and trees do not produce an obstruction without a need to ever reassess the existing height because ongoing maintenance ensures proper clearance.

Approach (Describe in general terms the steps you think are needed to achieve the objective.)

Gather information about existing practices and available technologies/systems. Potential examine information about tree growth rates to help model how regularly areas should be assessed for possible obstruction hazards. Conduct objective real world testing of various methods and equipment. Assess and report on the various options and methods recognizing that some airports may be more interested in more expensive high tech solutions while other airports may be interested in low tech low cost solutions.

Cost Estimate and Backup (Provide a cost estimate and support for how you arrived at the estimate.)

$300,000 - research will require literature review and other efforts to identify existing practices and technologies. Significant effort will be needed to determine which methodologies should be tested, how, and where. Actual field testing and analysis will require expertise and effective research protocols.

Related Research - List related ACRP and other industry research; describe gaps (see link to Research Roadmaps above), and describe how your idea would address these gaps. This is a critical element of a synthesis topic submission.

There is substantial information and research surrounding vertical obstructions, however most seems to deal with construction of new structures and zoning issues. Vegetation growth and monitoring strategies do not seem to have existing research that I could locate in the airport industry. An RTCA Tactical Operations Committee assembled a report on the 20:1 visual surface area issue published in January 2014.

Idea No. 279