Document
OAS-43A (12/12)
Interagency Aviation
Accident Prevention Bulletin
No. IA APB 26-03 March 11, 2026 Page 1 of 3 Subject: Low Level Environment and Wire Strike Avoidance Area of Concern: Flight Safety Distribution: All Aviation Operations Discussion When flying in mountainous terrain, or through canyons or river valleys, aircrews must be constantly aware that wires, cables, slacklines and other obstructions may be strung across the flight path.
These hazards often have poor visual conspicuity, especially against the backdrop of terrain or in certain lighting conditions.
A sport that is gaining in popularity, but that many aviators may not be familiar with, is slacklining. It is a balance sport similar to tightrope walking that uses a 1–2 inch nylon or polyester webbing stretched between two anchors, often trees or boulders. Unlike permanent structures such as powerlines, slacklines are often temporary and adjustable and therefore are not published on aeronautical charts. Even if filed, locating slackline hazards in the NOTAM system may be difficult. Figure 1 . Slackline across a canyon. Source: Envato Elements Safety Promotion and Awareness Slack Lining . In light of this growing sport, safety discussions regarding slacklines and other hazards in the low-level environment are ongoing within the aviation industry. To promote awareness of slacklining, a public website called SlackMap , provides a community- maintained map that voluntarily documents known slackline locations. While this map is not all-inclusive or endorsed in any way, it may provide potentially helpful information on known locations of these aerial hazards.
The NOTAM System . Finding hazards such as slacklines that have been filed in the NOTAM system can be daunting, as it often consists of looking through long lists Figure 2 . Slackline l ocations . Source: SlackMap.com that are not prioritized by severity or critical hazards. In fact, hazards may appear alongside minor advisories such as taxiway closures. This makes it difficult for local VFR flights to identify temporary obstacles along their route.
No. IAAPB 26-03 March 11, 2026 Page 2 of 3 • D NOTAMs (previously called Local NOTAMs) focus on more localized information affecting specific airports or regions. For example, these may include runway closures, construction work, or temporary obstacles in the vicinity of an airport.
Official FAA Methods for Checking NOTAMs Without ForeFlight 1. Using the FAA NOTAM Search website , enter departure, destination, and enroute airports or fixes. You can also filter by keywords (e.g., GPS, TFR, SUA). This is the most direct and official source for current NOTAMs.
2. Call Flight Service (1-800-WX-BRIEF) and request a standard briefing, specifically ask: “Please include enroute NOTAMs for my route of flight.” Flight Service Specialists are trained to provide NOTAMs for departure, destination, alternates, and enroute hazards. If your path passes within about 25 nautical miles of an airport, FSS will usually include NOTAMs for that airport as well.
3. FAA Chart Supplements & 28-Day NOTAM Publication. Review the FAA’s NOTAM Publication for recurring or long-term NOTAMs. This is especially useful for planning days in advance.
Practical Tips for GA Pilots 1. Include enroute waypoints or FIRs in your query. When using FAA NOTAM Search or briefing services, list major fixes or airports along your route.
2. Request “Route NOTAMs” on phone briefing. Don’t assume they’re included - specifically request them.
3. Check TFRs and SUA Activations. Use FAA TFR Map Website and sectional charts for low- level hazards.
4. Use free online tools such as SkyVector , SmartBriefing , or Airfield Watch to view METAR, TAF, and NOTAM data for your route.
Why This Matters NOTAMs are mandatory under 14 CFR 91.103 for preflight action. Reviewing the entire route—not just departure and destination—helps prevent surprises en route, supports accurate flight planning, and reduces the risk of violations or unsafe conditions. This proactive step is a key part of risk management and regulatory compliance in aviation.
No. IAAPB 26-03 March 11, 2026 Page 3 of 3 Summary Checklist: 1. FAA NOTAM Search (online).
2. Call Flight Service and request enroute NOTAMs.
3. Review TFRs and SUA via FAA sites.
4. Use supplemental tools like SkyVector or SmartBriefing for visualization.
5. If using ForeFlight, Garmin Pilot, or Other EFB applications, review available obstacle and NOTAM display tools. While not required, graphical overlays in these apps can help highlight temporary obstacles like slacklines during low-level flight. After reviewing enroute NOTAMs during preflight, ensure obstacle-related layers are enabled before departure. Bottom line: know your EFB’s obstacle-identifying tools—such as ForeFlight’s NOTAM map layer and Hazard Advisor or Garmin Pilot’s obstacle NOTAM icons—and understand how to activate and interpret them when needed.
/s/ Keith C. Raley /s/ Lori Clark Keith C. Raley Lori Clark Chief, Aviation Safety, Training, Program Branch Chief - Aviation Safety Evaluation, and Quality Management Management Systems DOI, Office of Aviation Services USDA, Forest Service