Close in Obstacles-what's the point?

[Checks]

Check out K2I0, Madinsonville, KY, Runway 5

NOTE: ​

​

​

​

​

​

Rwy 5, Vehicle on road 163' from departure end of
runway, 525' right of centerline, 15' AGL/434' MSL.
Vehicle on road 466' from departure end of runway, 597' left of centerline, 15' AGL/454' MSL. Rwy 23, Vehicle on road 563' from departure end of runway, 608' right of centerline, 15' AGL/464' MSL​

or

KHUG, Terre haut, IN

NOTE: ​

​

​

​

​

​

Rwy 5, Terrain beginning 118' from departure end​

of runway, left and right of centerline, 0' AGL/591' MSL.

The departure end of runway 05 is 583 MSL. Do I really need to know the terrain slopes up 8 feet? Aren't I crossing the DER at 35'?

Someone explain why the front of approach plates are littered with these things!

 

[MauleSkinner]

8 feet over 118 feet...that's almost 7% climb gradient. If you're 35 ft over the DER, and you're not making at least a 7% climb profile, your margins are getting smaller, not larger as they're designed to.

If you're operating under 135 or 121, you're going to have to make computational adjustments to remain legal.

The approach plates are littered with these things so that you DON'T have to make good on a 7% climb gradient just for 8 feet of terrain rise.

 

[Checks]

The point is this:

I am required to cross the DER at 35' thus in the KHUG example I am crossing at 618 ft MSL. What do I care if there is blades of grass at 591 ft MSL?

Seriously, isnt there 3 inch tall grass at the end of the runway, shouldnt that also be listed since it decreases my safety margin?

 

[MauleSkinner]

The point is this:

I am required to cross the DER at 35' thus in the KHUG example I am crossing at 618 ft MSL. What do I care if there is blades of grass at 591 ft MSL?

Seriously, isnt there 3 inch tall grass at the end of the runway, shouldnt that also be listed since it decreases my safety margin?

Under part 91 (except subpart K), you're not required to do anything but not hit something. Under 135 or 121, you're required to exceed minimum height above terrain/obstacles. 35 feet over the DER meets or exceeds the Part 91 requirement in this case, but not the 135 or 121 requirements.

 

[Checks]

OK, found the answer from the instrument procedures book but I still find it funny the FAA wastes it's time on terrain 8 feet higher than the DER. All it accomplishes is distracting pilots from reading the real obstacles that need avoided. The highlighted section below needs changed.

DESIGN CRITERIA​

The design of a departure procedure is based on TERPS, a living document that is updated frequently. Departure design criterion assumes an initial climb of 200 feet per nautical mile (NM) after crossing the departure end of the runway (DER) at a height of at least 35 feet. [Figure 2-15] The aircraft climb path assumption provides a minimum of 35 feet of additional obstacle clearance above the required obstacle clearance (ROC), from the DER outward, to absorb variations ranging from the distance of the static source to the landing gear, to differences
in establishing the minimum 200 feet per NM
climb gradient, etc. The ROC is the planned separation between the obstacle clearance surface (OCS) and the required climb gradient of 200 feet per NM. The ROC value is zero at the DER elevation and increases along the departure route until the appropriate ROC value is attained to allow en route flight to commence. It is typically about 25 NM for 1,000 feet of ROC in nonmountainous areas, and 46 NM for 2,000 feet of ROC​

in mountainous areas.

 

[MauleSkinner]

OK, found the answer from the instrument procedures book but I still find it funny the FAA wastes it's time on terrain 8 feet higher than the DER. All it accomplishes is distracting pilots from reading the real obstacles that need avoided. The highlighted section below needs changed.
​

So...you figure 35 feet of terrain separation is fine until you level off in cruise?

 

[Checks]

I never wrote that. Where do I say it is ok to be 35ft until cruise? If you cross the DER at 35ft then you can not possibly hit terrain that is 27 ft below you.
It is impossible.

 

[MauleSkinner]

Well, then, if you're flying Part 91, you're probably legal to ignore it.

 

[Checks]

Ignore it or not, you won't do one thing different knowing there is terrain 118' away that goes up a whopping 8'. What the FAA really needs to do is evaluate the OCS starting at 35ft DER not zero feet at DER and the problem would be solved.
Anyways, please dont respond I can't stand your responses.....you sound like a current/former FAA talking head.

 

[MauleSkinner]

Ignore it or not, you won't do one thing different knowing there is terrain 118' away that goes up a whopping 8'.

Maybe, maybe not...depends on how the calcualtions work out.

What the FAA really needs to do is evaluate the OCS starting at 35ft DER not zero feet at DER and the problem would be solved.

Solves some, creates more.

Anyways, please dont respond I can't stand your responses.....you sound like a current/former FAA talking head.

No, just a pilot who takes not flying into stuff seriously, as well as not canceling a trip because the FAA decided not to give me the options that your idea takes away.