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Questions tagged [obstacle-clearance]

For questions on obstacle clearance, whether en route or on a procedure (departure and arrival), including the operational and regulatory aspects.

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Is 200FPNM required up to the MSA or to the MOCA in the PLMTO3 SID

On the PLMTO3 SID out of KCHS, Rwy 15 has standard takeoff mins. From the AIM 5-2-9.e.1. Unless specified otherwise, required obstacle clearance for all departures, including diverse, is based on the ...
Name's user avatar
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1 answer
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EOSID - Adhere to at or soon after V1?

Most airports have an Engine Out Standard Instrument Departure (EOSID) statement similar to this on their charts: For EOSIDs, the take-off performance for "ABC Airport" is based on the ...
shogunnyan's user avatar
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MOC for CAT III missed approach segment

Hello what is the MOC (minimum obstacle clearance) for missed approach segment for CAT III ILS minimum ?
Edvin Simic's user avatar
4 votes
2 answers
363 views

If an Airport has only a VCOA and a SID, does the VCOA count as an ODP, and if not, does that mean you can fly a diverse departure?

KGRF has a SID requiring a climb gradient of 469 FPNM for obstacles. In the takeoff minimums section, there are takeoff minimums listed for a VOCA (Visual Climb Over Airport) but nothing else. My ...
Name's user avatar
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Why do heli PC2 operations require highest obstacle clearance

In designing a helipad I notice that the Australian requirements (AC139.R-01) for obstacle clear gradients specify that the slope category (12.5% slope) generally applies to PC2 operations, whereas ...
Paul Haubourdin's user avatar
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1 answer
3k views

What is the difference between MOCA and OCA?

Can someone explain me the difference between minimum obstacle clearance altitude and obstacle clearance altitude? I read definitions in Doc 8168 but i don't really see the difference. I would be ...
Konrad's user avatar
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7 votes
2 answers
859 views

What's IFR departure procedure from private field with encroaching obstacles but no published ODP?

So, this question's answer says that, absent a published ODP, I should be 35' above DER, and on a 200'/NM climb. But the airfield in the town I grew up in, 26MA, has no ODP; but 200'/NM isn't even ...
William Walker III's user avatar
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1 answer
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How should this ODP be flown at KELP?

The KELP (El Paso) Obstacle Departure Procedure (ODP) says: Rwy 4, 8R: climbing right turn heading 120° and ELP R-150 to 9000, then proceed on course. Rwy 22, 26L: climbing left turn heading 120° and ...
chup's user avatar
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1 vote
1 answer
237 views

During an LPV or GLS final approach, can the extension of the aircraft's cross-section line intersect with the Y or X OCS surfaces?

I am studying Obstacle Clearance Surface construction using FAA's Performance Base Navigation manual 8260.58B as my guide. I am confused about the rules concerning aircraft's permitted altitude in ...
Vector Zita's user avatar
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2 votes
1 answer
164 views

A Question about Departure Procedures at KLRU

The Las Cruces International Airport has the following text in the Takeoff Minimums and ODP document: LAS CRUCES, NM LAS CRUCES INTL (LRU) TAKEOFF MINIMUMS AND (OBSTACLE) DEPARTURE ...
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What is the difference in purpose of the 1:40 Obstacle Identification Surface and the 1:50 clearance plane for an ILS glideslope?

I have found references to the Obstacle Identification Surface (OIS), which is approximately a 152ft/NM slope from the end of the runway (1.43 degrees, 1:40 rise/run) and a 1:50 clearance plane noted ...
Ryan Mortensen's user avatar
2 votes
1 answer
406 views

What does "Controlling Object" mean in FAA documentation?

I was examining FAA's legacy files, which contain information for various airspace elements, and I noticed that there is a field in the airport layout file called "Controlling Object", for both base ...
Vector Zita's user avatar
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4 votes
3 answers
2k views

How much clearance is provided when taking off over a 50 foot obstacle?

When performing a takeoff over a 50' obstacle, how much clearance is provided between the obstacle and the aircraft and where can that be found?
Sean Mahaffey's user avatar
0 votes
1 answer
60 views

What are early/inside and late/outside turns (see, e.g., PBN Manual Order 8260.58A) and when do pilots perform them?

While studying FAA's PBN Manual (Order 8260.58A), I came across the concept of early/inside and late/outside turn construction (Section 5-3. Turning Departures). For each of the possible cases, it ...
Vector Zita's user avatar
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1 vote
1 answer
306 views

How to accurately determine Navigation Accuracy from FAA's PBN Criteria (Order 8260.58A)?

I am trying to understand how to determine the Navigation Accuracy for a given flight phase of an Instrument Flight Procedure, from the US Standard for PBN Instrument Procedure Design (Order 8260.58A)....
Vector Zita's user avatar
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8 votes
1 answer
1k views

Why does obstacle clearance area splay outward instead of being a rectangle?

I am having trouble figuring out the logic behind the way that obstacle clearance areas are constructed. Take, for example, a departure procedure where Initial Climb Area is defined in TERPS (section ...
Vector Zita's user avatar
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