IFR Departure Procedures

[Up and Locked]

In the following scenario what would be the right thing to do?

A 19 passenger turbo-prop is doing an IFR departure from a non-radar airport under part 121 rules. The weather is good VFR. The obstacle clearance departure procedure for the departure runway calls for a climb, runway heading, to 700 feet above airport elevation before turning on course.

After takeoff, tower calls, “(any airline flight) turn left to a heading of 150 degrees.” The heading would require a 45 degree hading change as the aircraft is climbing through 400 feet. Should the crew ignore the clearance and follow the obstacle clearance procedure, or should they comply? I think they should comply but I can’t find anything official to document my beliefs.

 

[vclean]

You're VFR and can follow the tower's instructions. Obstacle clearance on a departure procedure is critical during OEI operations. Minimum performance standards for Part 25 Transport Category Aircraft require a 35' net obstacle clearance on the final segment climb. This is only of concern if you lost an engine after V1. If you're IMC, the tower won't have you fly something other than the DP. Flying VMC, you can avoid the terrain, and the tower may have you turn differently to increase flow.

 

[Vector4fun]

I don't have any idea what Part 121 says about the above scenario, but if I had a dollar for every IFR Part 121 carrier that's asked me (in the tower) for a VFR climb over a mountain pass at 1000-2000' BELOW the MVA for that sector, I could purchase a very nice car......


And they weren't 19 pax turboprops either!

 

[Up and Locked]

Thanks

Thanks for the fast response. Sometimes I know I'm right and just need a little confirmation.

 

[Mr. Irrelevant]

Flying VMC, you can avoid the terrain, and the tower may have you turn differently to increase flow.

Didn't the Air Force have a c-130 slam into a mountain climbing out of Jackson Hole back in 96 after one of Clinton's vacations?? That was in Night VFR conditions I believe. I know what you're saying about being able to see and avoid in VMC but at night that goes out the window. That crew in Jackson Hole did not fly the departure procedure.

If it's night time in a mountainous area (and I don't fly in that area often) I would request to fly the departure procedure.


Mr. I.

 

[profile]

This has been a problem for a while. The tower assigning a heading in non-radar, where the tower is not assuming responsibility for terrain clearance. Some airports have a designated departure area that the tower can use for assigning such headings, but many do not. Trouble is, the pilot has no way of knowing whether ATC assumes terrain separation or not in this scenario. Day VMC may not be a problem, but night it sure could be. Best to ask if there is any doubt.

As for operators asking for "VFR climbs" to avoid terrain, that is a violation of the ops specs for turbojet 135/121 or any 121 operator, as it is considered similar to asking for VFR on top, under the regs. This was pounded out by ALPA in about 1995, and there are legal letters of interp from the FAA chief counsel on the topic. It cannot be waived unless you've received a point on point specific authorization from FAA hq (guessing AFS-400 or maybe 200, although AGC-1 would be better), not the region, not the POI, let alone a local FSDO.

 

[The FNG]

The Airport Analysis runway column provides the zero wind weight assuring obstacle clearance, as well as take-off and accelerate stop. If there is data for the runway in question it incorporates the performance necessary to preclude needing the obstacle clearance departure procedure (there should be a minimum rate of climb qualifier on the chart).

 

[GogglesPisano]

In VMC conditions, if the PIC can assure his own obstruction clearance, he may ignore the IFR DP.

He may initiate a turn after TO IAW his FOM.

I like to abbreviate.