Minimum Safe Altitude Warning

1. Minimum Safe Altitude Warning Asian Regional Aviation Safety Team (ARAST), Bangkok, Thailand Glenn W. Michael Air Traffic Manager, Boston ARTCC November 19, 2008

2. MSAW Course Overview • Safety – Risk Management – Mitigation – Risk Assessment • GASR (Global Aviation Safety Roadmap) • CFIT (Controlled Flight Into Terrain) • ICAO efforts to prevent CFIT • EGPWS (Enhanced Ground Proximity Warning Systems)

3. Overview (cont) • A general overview of MSAW • Accident Investigations • Air Traffic Control procedures and MSAW • MSAW Development

4. The safety enhancement system remains highly dependent on • human performance • especially in the cockpit • at the air traffic controller station • and with those charged with enforcing and monitoring standard operating procedures and best practices and procedures

5. “Mitigation” (System Defenses) • The measures taken or proposed to eradicate the hazard or to reduce the probability or the severity of a risk.

7. Order of Precedence for Hazard Mitigation • Modify the system – design the hazard out • Physical guards or barriers – prevent the risk from occurring • Warning or alert signal • Procedural and training change • Advise people – placards, notices, brief all pilots, etc.

8. Controlled Flight Into Terrain (CFIT) • A controlled-flight-into-terrain (CFIT) accident is one in which an otherwise serviceable aircraft, under the control of the crew, is flown (unintentionally) into terrain, obstacles or water, with no prior awareness on the part of the crew of the impending collision

9. Ground Based Prevention of CFIT • ATC Safety Net What ground-based intervention would have prevented the accident? • Automated tools provide the means for ATC to strengthen overall defenses against CFIT • Minimum Safe Altitude Warning (MSAW)

10. Minimum Safe Altitude Warning • A function designed solely as a controller aid in detecting potentially unsafe aircraft proximity to terrain/obstructions • Generates and alert to the controller when a pilot is below, or is predicted to be below, a specified altitude • Must be adapted specifically for each RADAR system

11. Minimum Safe Altitude Warning (cont) • Types of MSAW Processing • General Terrain Monitoring • Approach Path Monitoring

12. Minimum Safe Altitude Warning (cont) • General Terrain Monitoring • Current Alarm • Presently less than 500 feet above terrain map • Prediction Alarm • Pilot will be less than 500 feet above terrain map within 30 seconds • Projection Alarm • Pilot will be unable to clear all obstacles within eight minutes flying time on present course at a five degree climb angle

13. Minimum Safe Altitude Warning (cont) • Approach Path Monitor • Current • Pilot is currently below the calculated APM alarm slope altitude • Prediction • Pilot is predicted to be 100 feet below the calculated APM alarm slope altitude within the next 15 seconds

14. MSAW Approach Path Monitoring Glideslope Path Alarm Trigger Area (100´ below glideslope path) Runway 1 nm

15. MSAW: Safety-Critical? • FAA: Safe operation of aircraft is ultimately pilots’ responsibility. • MSAW is an aid to AT controllers • MSAW only ground-based CFIT barrier

16. MSAW • Procedures and phraseology • ICAO order • Procedures for Air Navigation Services – Air Traffic Management (PANS-ATM) Document 4444 • Chapter 15 Para. 15.6.4 Minimum Safe Altitude Warning (MSAW) Procedures