Instrument Tip: An ejection handle

One option is to climb. You can’t shoot the missed approach because you don’t have a navigation source. Continuing the approach isn’t an option either. Holding a heading and continuing a controlled descent might get you on the ground safely, but there’s no guarantee you won’t hit anything. The only truly safe option is to climb, but where to? The minimum safe altitude.

The minimum safe altitude is an altitude, or series of different altitudes, that provide 1,000 feet of obstacle clearance in the general airport area. Think of it like an ejection handle. If you’re facing the worst, the MSA gives you a fighting chance by clearly defining an altitude that will at least ensure you don’t hit anything.

MSAs are depicted on all instrument approach procedures, with the exception of RNAV approaches with the classic T shape. There, MSAs are replaced with approach altitudes that provide the same level of safety, albeit in a slightly different format.

You can find the MSA on the plan view of approach charts. Look for the circle with the waypoint in the middle. That waypoint designates the center point of the protected area. Typically it will be the navaid upon which the approach is based, but it could be an intermediate fix, or even the airport reference point. Often the protected area is a 25-mile radius from that point, but it can expand out to 30 miles.

At the top of the MSA circle you’ll see the letters “MSA” then a three-letter identifier that indicates the waypoint upon which the protected area is based. Finally, the protected distance is listed in nautical miles. Inside the circle is the altitude or altitudes, and if more than one altitude, the various radials or bearings that define the sectors. There can be up to four of these different sectors in an MSA circle.

For RNAV approaches the minimum safe altitude is listed according to the arrival area. It’s always on the plan view, and is usually defined by the intermediate fix as the center point and then two radii and a semi-circle that show the defined area. Like an MSA, an altitude will be inside.

MSAs are generally used only in cases of emergency. When things get really bad you know you can climb up to the listed altitude and have at least 1,000 feet of obstacle clearance. That said, the MSA doesn’t imply an ability to receive navigation information. So you could be flying blind.

There are many scenarios where climbing to the MSA could be a safe tactic. NASA’s safety database has dozens of cases of airline pilots immediately climbing to the MSA after receiving a terrain warning on an approach. Other pilots have become lost on approach and decide to climb to the MSA. Some do it because they don’t trust an ATC instruction.

Because the MSA is such an important resource of last resort, include it in your approach briefing. When things get out of hand on the approach, or you need an escape route, it’s there as a way to ensure you can at least take the time to evaluate the problem safely.