Proper altitude to start enroute

8 Answers

1. 
   

   
   

   John D Collins on Apr 19, 2020

   It very much depends on the type of departure you were cleared for an ODP, a SID or a
   DVA.

   In general, you are expected to remain on runway heading until cleared otherwise by a new clearance, like proceed on course contact departure or if you are just told to contact departure, you would remain on the runway heading in the climb until given a vector or other clearance or instruction. When the initial heading will take the aircraft off an assigned procedure from the departure end of runway, the controller will assign an altitude to
   maintain with the initial heading.

   These are the instructions given to controllers:

   Departure Procedures.
   1. Specify direction of takeoff/turn or initial heading to be flown after takeoff as follows:
   (a) Locations with Airport Traffic Control Service−Specify direction of takeoff/turn or initial
   heading as necessary, consistent with published:
   (1) Departure Procedures (DP). If an aircraft is vectored off a published Standard Instrument Departure (SID) or Obstacle Departure Procedure (ODP), that vector cancels the DP and
   ATC becomes responsible for separation from terrain and /or obstructions. IFR aircraft must be assigned an altitude.
   (2) Diverse Vector Areas (DVA). The assignment of an initial heading using a DVA can be
   given to the pilot as part of the initial clearance, but must be given no later than with the takeoff clearance. Once airborne, an aircraft assigned headings within the DVA can be vectored below the MVA/MIA. Controllers cannot interrupt an aircraft’s climb in the
   DVA until the aircraft is at or above the MVA/MIA.

   If you are simply cleared for takeoff, climb to 400 feet before turning on course.

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2. Best Answer
   
   

   
   

   Larry Brock on Apr 19, 2020

   For example. On an IFR clearance, you are given a DVA. At what altitude can you change from runway heading to DVA issued before takeoff?

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3. 
   

   
   

   Mark Kolber on Apr 20, 2020

   above 400 AGL.

   Read AIM 5-2-9 and equivalent information and guidance.

   “Unless specified otherwise, required obstacle clearance for all departures, including diverse, is based on the pilot crossing the departure end of the runway at least 35 feet above the departure end of runway elevation, climbing to 400 feet above the departure end of runway elevation before making the initial turn,”

   I think too many people treat that as a command to turn immediately upon reaching 400 AGL. We are talking about flight without visual reference so one does need to turn expeditiously. In the case of an ODP, one may need to initiate that 400′ right away. ATC’S expectation is that you won’t dally.

   But a reasonable climb a few hundred feet higher if the pilot thinks safe operation requires it is not going to get ATC’s panties in a knot. At worst there will be a follow up instruction to “start turn now” if you are in the way.

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4. 
   

   
   

   Larry Brock on Apr 20, 2020

   I see many pilots, including very experienced airline pilots (flying GA) and instructors, turning BEFORE 400’, hence the question. I know the regulations say 400 feet, but I have even been hurried to turn before 400’ by tower, on instrument flight plans (no ODP or SID). So, is that normal?

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5. 
   

   
   

   Mark Kolber on Apr 20, 2020

   Normal? No. Happens when Tower wants you out of the way? Sure. even VFR. Can you say “unable until XX feet” if you feel it’s unsafe to hurry your turn? Yes. Never let some guy sitting comfortably on the ground dictate that you do something unsafe in the air.

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6. 
   

   
   

   John D Collins on Apr 20, 2020

   I am not aware of any regulations that dictate no turns before 400 AGL 400 feet is based on criteria for DP and guidance from the AIM. Normal guidance is to climb to 400 AGL before turning on course, in this case a heading. An ODP may require a climb to an altitude before turning on course or a non standard climb gradient for either an ODP or a DVA.

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7. 
   

   
   

   Larry Brock on Apr 20, 2020

   So, if I understand you correctly, a safe turn to assigned heading can be taken at any altitude before 400 agl if there is no ODP or SID to instruct otherwise?

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8. 
   

   
   

   John D Collins on Apr 20, 2020

   Larry,

   That is not what I said. I was simply noting that there isn’t a regulation that requires the climb to 400 feet AGL before turning on course.

   You wrote:

   “I know the REGULATIONS say 400 feet, but I have even been hurried to turn before 400’ by tower, on instrument flight plans (no ODP or SID). So, is that normal?”

   I was pointing out that your assertion that “I know the REGULATIONS say 400 feet” is not an accurate statement. It is “guidance” that says not to turn until 400 feet and it is based on the fact that each airport that has instrument approaches has the runways evaluated for an Initial Climb Area (ICA) that covers the first two miles off the departure end for close-in obstacles. The takeoff minimums provide information on each runway, and if the entry is silent, then the standard climb gradient of 200 feet per mile for a climb to the MIA is appropriate. It will include clearance of obstacles in the ICA on a 40 to 1 slope for the ICA and continuing out up to 25 NM (46 NM in mountainous areas) if needed to reach the MIA.

   You wrote it was VFR conditions, so you can see any obstacles and determine for yourself when it is safe to commence a turn. There isn’t a regulation involved. If you were not in visual conditions, you know it would be safe to commence the turn after climbing to 400 feet AGL.

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