This chart illustrates the importance of noticing everything written on the chart. A note is included, stating we will use normal sensing outbound on the I-PKN back course. A pilot would be very confused if he expected to see reverse sensing when trying to join this course. Needless to say, being surrounded by mountains you can’t see and confused is a very bad thing. This note is included to make absolutely sure we understand we should anticipate normal sensing to track the course.
Also, take note of the takeoff minimums. If we couldn’t takeoff from runway 33, then we’re stuck in Aspen. This departure procedure states that runway 15 is not available because there is just too much terrain that way. It’s just not possible to safely depart runway 15 by reference to instruments only. To depart from runway 33, the weather must be at least a 400 foot ceiling and 1 mile visibility, and the airplane must be able to maintain a climb gradient of 460 feet per nautical mile to 14,000 feet. If you don’t have that weather or your airplane can’t make the climb gradient, you’re stuck.
Even if you on an IFR clearance, you can maintain separation from terrain visually. With good weather, it is unlikely that you would be assigned the Sardd Three Departure. In this case, it is up to you to determine if you can safely depart and climb to the minimum enroute altitude along your route. Maybe your airplane is even capable of departing runway 15, and you feel comfortable clearing the terrain visually.
On the other hand, you might be more comfortable just complying with the departure procedure. Even on a good weather day, when air traffic control does not assign the obstacle departure procedure, you can still fly the procedure. Just let air traffic control know your intentions, so they can plan accordingly. They will not be happy if you, for example, enter holding at LINDZ without letting them know. In this case, you could simply file the departure procedure or request it from clearance delivery.
Where an obstacle departure does not exist for an airport, takeoff minimums and departure procedures may still exist. If we were to depart from Cincinnati’s Lunken airport, we would still have some restrictions and procedures to follow, even if no departure procedure was assigned in our clearance. For a departure of runway 3L at Lunken, a minimum climb gradient of 392 feet per nautical mile to 1,000 feet is required. With at least a 400 feet ceiling and 2 miles of visibility, the gradient can be reduced to 213 feet per NM to 1400 feet. Only if the weather is greater than 1700 and 2 ½ may the pilot climb in visual conditions with whatever climb gradient the pilot determines appropriate. Additionally, we are required to fly a 027 heading off of runway 3L, until reaching 1200 feet, unless climbing in visual conditions. In that case, we are required to climb to at or above 2000 feet over the airport before turning on course. It is the pilot’s responsibility to determine whether such restrictions or procedures exist and follow them.
Departure procedures may be referred to as DP’s. Alternatively, they may be called SIDs, short for standard instrument departures.
Reference: FAR 91.121, 183, 187
Reference: AIM 5-2: Departure Procedures
Reference Instrument Flying Handbook 10-5: Departure Procedures