Instrument flying is mostly predictable and routine, but these 7 instrument approaches will keep you on your toes.

1) VOR/DME Runway 15 into Baltimore / Martin State (KMTN)

Unlike many approaches, the VOR/DME into Runway 15 at KMTN is one big DME arc. Each fix along the approach is a DME radial, and the final approach course is constantly curving.

2) NDB/DME-A into Hailey / Friedman Memorial (KSUN)

The procedure turn for this approach is flown at 8,100 feet, and you only get to descend 60 feet to an MDA of 8,040 feet. The missed approach point is 5.2 NM from the runway, and you must fly 100% visually from the MAP to the runway.

3) LOC/DME-E into Aspen-Pikin County (KASE)

The localizer approach into Aspen requires pilots to chop and drop nearly 1,900 feet in just 3.1NM. The prescribed approach angle is 6.59 degrees. It terminates with a missed approach that turns you onto a remotely located mountaintop localizer for a back-course departure, through a valley, to the waypoint LINDZ.

4) RNAV (GPS)-A into Anaktuvuk Pass (PAKP)

The RNAV into Anaktuvuk has extremely high 4,000 foot AGL minimums, which makes sense considering the terrain surrounding the airport. Its single runway (02/20) is gravel, making it one of just a few unpaved airports in the country with published instrument approaches.

5) NDB Runway 34 into Sparrevohn LRRS (PASV)

This NDB approach takes pilots into a runway with a nearly 5 degree upslope. It's published with some unique warnings, like "successful go-around improbable if initiated past the MAP" (due to sharply rising terrain).

6) VOR/DME-A into Watsonville Municipal (KWVI)

This strange DME arc to the final approach course has pilots turn outbound, away from the VOR, for the off-field VOR approach.

7) RNAV RNP Runway 19 into Washington National (KDCA)

The lowest minimums for this curving approach (491 foot DA) require RNP precision of 0.11 miles. Plus, you don't want to accidentally bust the prohibited airspace above the White House and Capitol that's just .3NM North of the final approach course.

What other unique instrument approaches are out there? Tell us about them in the comments below.