Part ## and Part ###’s Takeoff Minimums

[luvflyin]

91.175 (f) Civil airport takeoff minimums. This paragraph applies to persons operating an aircraft under part 121, 125, 129, or 135 of this chapter.

There it is in black and white. Now we all know that doesn’t apply to Part 91. We’ve heard it time and time again. So, what is the logic in putting something in Part 91 that does not apply to Part 91??

 

[k9medic]

Circular reference to make sure somebody under 135 or 121 doesn't try to say "well part 91 says..."

 

[MauleSkinner]

Part 91 applies to Part 121, 125, and 135 operations as well.

 

[aterpster]

Part 91 applies to Part 121, 125, and 135 operations as well.

Parts 121, 125, and 135 don't apply to operations conducted solely under Part 91.

 

[MauleSkinner]

Parts 121, 125, and 135 don't apply to operations conducted solely under Part 91.

Correct…but the reverse is not true.

 

[aterpster]

Correct…but the reverse is not true.

 

[luvflyin]

Part 91 applies to Part 121, 125, and 135 operations as well.

Ok. And Part 91 applies to Part 91 operations. Except 91.175 (f) apparently.

 

[MauleSkinner]

Ok. And Part 91 applies to Part 91 operations. Except 91.175 (f) apparently.

In an un-FAA-like move, they kept the takeoff and landing requirements in one place instead of spreading them around.

 

[aterpster]

Ok. And Part 91 applies to Part 91 operations. Except 91.175 (f) apparently.

Yes. But they had to keep that section in Part 91 because some of 91.175(f) applies to 121, 125, and 135, and some applies only to 121 and 135.

 

[MauleSkinner]

Yes. But they had to keep that section in Part 91 because some of 91.175(f) applies to 121, 125, and 135, and some applies only to 121 and 135.

And the rest of 91.175 applies to operations under all parts.

 

[aterpster]

And the rest of 91.175 applies to operations under all parts.

What I was saying 91.175(f) could have been moved to 121, 125, and 135 except for the split between chose parts. That would make it less confusing for 91-only operators. Even one of the regular writers for Business and Commercial Aviation doesn't understand that 91-only operators can elect not to fly ODPs (unless part of the ATC clearance), and are not bound to takeoff minimums.

 

[MauleSkinner]

Even one of the regular writers for Business and Commercial Aviation doesn't understand that 91-only operators can elect not to fly ODPs (unless part of the ATC clearance), and are not bound to takeoff minimums.

Probably for the same reason (valid or not, but I would lean towards “not”) that there’s no reg specifically requiring Part 91-only operators to clear obstacles.

 

[Doc Holliday]

You guys way overthink this stuff.

 

[aterpster]

Probably for the same reason (valid or not, but I would lean towards “not”) that there’s no reg specifically requiring Part 91-only operators to clear obstacles.

91.13, unless you are by yourself and don't CFIT into persons or improved property.

 

[luvflyin]

You guys way overthink this stuff.

 

[Palmpilot]

What I was saying 91.175(f) could have been moved to 121, 125, and 135 except for the split between chose parts. That would make it less confusing for 91-only operators. Even one of the regular writers for Business and Commercial Aviation doesn't understand that 91-only operators can elect not to fly ODPs (unless part of the ATC clearance), and are not bound to takeoff minimums.

One of the unintended consequences of the part I highlighted is that some pilots (myself formerly included) are unaware that an ODP does not guarantee terrain and obstruction clearance unless you meet the minimum climb gradients in the takeoff minimums.

https://www.pilotsofamerica.com/community/threads/odp-and-takeoff-minimum-climb-gradients.132569/

 

[aterpster]

One of the unintended consequences of the part I highlighted is that some pilots (myself formerly included) are unaware that an ODP does not guarantee terrain and obstruction clearance unless you meet the minimum climb gradients in the takeoff minimums.

https://www.pilotsofamerica.com/community/threads/odp-and-takeoff-minimum-climb-gradients.132569/

In a perfect world all ODPs would be charted and any climb gradient associated with that ODP be publish on the ODP chart, not the takeoff minimums section. And, the old argument "well that is yet another piece of paper" doesn't compute in year 2021. And, there are many ODPs that should be charted simply because of their complexity, but are not. (KPUC for instance.)

 

[Ryan F.]

One of the unintended consequences of the part I highlighted is that some pilots (myself formerly included) are unaware that an ODP does not guarantee terrain and obstruction clearance unless you meet the minimum climb gradients in the takeoff minimums.

https://www.pilotsofamerica.com/community/threads/odp-and-takeoff-minimum-climb-gradients.132569/

That is a practical test subject I always include on every instrument rating and CFI-IA ground portion - I expect applicants to understand that climb gradients do apply to them under Part 91, and that by accepting a SID they're agreeing that their aircraft performance is adequate to meet those climb gradients.

 

[luvflyin]

That is a practical test subject I always include on every instrument rating and CFI-IA ground portion - I expect applicants to understand that climb gradients do apply to them under Part 91, and that by accepting a SID they're agreeing that their aircraft performance is adequate to meet those climb gradients.

Nitpick. Change SID to DP. Both kinds, SID’s and ODP’s. There is enough confusion out there about Departures that maybe that isn’t all that nitpicky.

 

[aterpster]

That is a practical test subject I always include on every instrument rating and CFI-IA ground portion - I expect applicants to understand that climb gradients do apply to them under Part 91, and that by accepting a SID they're agreeing that their aircraft performance is adequate to meet those climb gradients.

Yes, as to SIDs. No, as to ODPs. The latter is the not-for-hire pilot option as to compliance, unless the ODP is part of the air traffic clearance.

 

[MauleSkinner]

One of the unintended consequences of the part I highlighted is that some pilots (myself formerly included) are unaware that an ODP does not guarantee terrain and obstruction clearance unless you meet the minimum climb gradients in the takeoff minimums.

https://www.pilotsofamerica.com/community/threads/odp-and-takeoff-minimum-climb-gradients.132569/

Just to clarify what 91.175(f) is referring to with regard to ODPs and climb gradients…if an ODP is published, that’s basically the only routing that the FAA has evaluated as clearing obstacles from that runway. No diverse departures are evaluated.

(f)(3) says that Part 1## operators are required to fly a departure path that has been evaluated and approved, therefore they must fly the ODP if one exists.
(f)(4) adds the option for the operator to create or purchase an alternate procedure that meets obstacle requirements (separate from TERPS, actually...that’s the Advisory Circular mentioned), but that includes knowledge of where the individual obstacles are located.

Since Part 91 operators are not required to fly the ODP, implication is that there are other acceptable ways to clear obstacles, and you can use local knowledge or whatever means to determine an alternate procedure without the requirement for specific FAA approval. As long as you don’t crash or consistently set off altitude alarms with ATC, they probably won’t concern themselves with exactly how you depart.

Keep in mind, also, that there may be “close in” obstacles within 1 mile of the departure end of the runway, up to 200 feet tall, that are not included in ANY climb gradient evaluation that the FAA has done, whether ODP or standard 200 ft/mile. To look at your KTVL example, runway 36 shows these:

since most takeoffs don’t use every foot of runway, the FAA allows you to use the runway you don’t use to reduce the climb gradient required, and so these close in obstacles are often not an issue.

 

[MauleSkinner]

That is a practical test subject I always include on every instrument rating and CFI-IA ground portion - I expect applicants to understand that climb gradients do apply to them under Part 91, and that by accepting a SID they're agreeing that their aircraft performance is adequate to meet those climb gradients.

Nitpick. Change SID to DP. Both kinds, SID’s and ODP’s. There is enough confusion out there about Departures that maybe that isn’t all that nitpicky.

Yes, as to SIDs. No, as to ODPs. The latter is the not-for-hire pilot option as to compliance, unless the ODP is part of the air traffic clearance.

Would we all be in agreement that for a Part 91 operator, if you accept a DP as part of your clearance, whether it’s an ODP or a SID, you are agreeing to meet any climb gradient specified as part of that procedure?

 

[aterpster]

Would we all be in agreement that for a Part 91 operator, if you accept a DP as part of your clearance, whether it’s an ODP or a SID, you are agreeing to meet any climb gradient specified as part of that procedure?

I already agreed with that about three messages ago.

 

[Ryan F.]

Nitpick. Change SID to DP. Both kinds, SID’s and ODP’s. There is enough confusion out there about Departures that maybe that isn’t all that nitpicky.

My scenario involves a SID, specifically. The other comments from MauleSkinner are pertinent.

 

[JScarry]

Yes, as to SIDs. No, as to ODPs. The latter is the not-for-hire pilot option as to compliance, unless the ODP is part of the air traffic clearance.

By flying under IFR you are acknowledging that your aircraft can depart the airport and climb at standard IFR climb rate of 200' per nautical mile. ODPs are constructed with that in mind (also no turns before 400' AGL). If a SID requires more than that, it is noted on the SID. Non-standard climb rates are indicated in the text of an ODP as well. e.g. Big Bear City. Diverse area departures also assume the standard IFR climb rate.

 

[luvflyin]

By flying under IFR you are acknowledging that your aircraft can depart the airport and climb at standard IFR climb rate of 200' per nautical mile. ODPs are constructed with that in mind (also no turns before 400' AGL). If a SID requires more than that, it is noted on the SID. Non-standard climb rates are indicated in the text of an ODP as well. e.g. Big Bear City. Diverse area departures also assume the standard IFR climb rate.

What’s assumed is that all aircraft will climb at least 200’ per nautical mile. If that’s not enough to depart in any direction, then an ODP will be constructed. ODP’s have minimum climb gradients. It can be so hilly around there that they can’t find a 200 per mile way through in any direction. So they do the best can. Find the way that requires the least onerous climb gradient. SID’s are not bound by finding the least onerous way. SID’s purpose is not terrain clearance. There purpose is to reduce verbiage and accommodate air traffic flow. BUT, they must meet same obstacle clearance criteria as ODP’s. Because they are not trying to find the ‘shallowest’ way so to speak, the often have climb gradient requirements steeper than an ODP out of the same airport/runway.

 

[MauleSkinner]

My scenario involves a SID, specifically. The other comments from MauleSkinner are pertinent.

Pleasant change from my normal impertinence, isn’t it?

 

[luvflyin]

Just to clarify what 91.175(f) is referring to with regard to ODPs and climb gradients…if an ODP is published, that’s basically the only routing that the FAA has evaluated as clearing obstacles from that runway. No diverse departures are evaluated.

(f)(3) says that Part 1## operators are required to fly a departure path that has been evaluated and approved, therefore they must fly the ODP if one exists.
(f)(4) adds the option for the operator to create or purchase an alternate procedure that meets obstacle requirements (separate from TERPS, actually...that’s the Advisory Circular mentioned), but that includes knowledge of where the individual obstacles are located.

Since Part 91 operators are not required to fly the ODP, implication is that there are other acceptable ways to clear obstacles, and you can use local knowledge or whatever means to determine an alternate procedure without the requirement for specific FAA approval. As long as you don’t crash or consistently set off altitude alarms with ATC, they probably won’t concern themselves with exactly how you depart.

Keep in mind, also, that there may be “close in” obstacles within 1 mile of the departure end of the runway, up to 200 feet tall, that are not included in ANY climb gradient evaluation that the FAA has done, whether ODP or standard 200 ft/mile. To look at your KTVL example, runway 36 shows these:
View attachment 97237
since most takeoffs don’t use every foot of runway, the FAA allows you to use the runway you don’t use to reduce the climb gradient required, and so these close in obstacles are often not an issue.

Watch out for them vehicles

 

[Palmpilot]

Since Part 91 operators are not required to fly the ODP, implication is that there are other acceptable ways to clear obstacles, and you can use local knowledge or whatever means to determine an alternate procedure without the requirement for specific FAA approval. As long as you don’t crash or consistently set off altitude alarms with ATC, they probably won’t concern themselves with exactly how you depart.

That's what I ended up doing; I think the Rwy 36 ODP did not exist when I made the flight I mentioned. I told Center that I could maintain my own terrain and obstruction clearance, and I climbed slightly to the west of the localizer, so as to make sure I stayed over the lake until they had radar contact and could provide vectors.

Keep in mind, also, that there may be “close in” obstacles within 1 mile of the departure end of the runway, up to 200 feet tall, that are not included in ANY climb gradient evaluation that the FAA has done, whether ODP or standard 200 ft/mile. To look at your KTVL example, runway 36 shows these:
View attachment 97237
since most takeoffs don’t use every foot of runway, the FAA allows you to use the runway you don’t use to reduce the climb gradient required, and so these close in obstacles are often not an issue.

Fortunately, the ceiling was high enough to avoid the close-in obstacles visually. BTW, how do you "use the runway you don’t use"?

I guess you mean the extra runway length.

 

[MauleSkinner]

That's what I ended up doing; I think the Rwy 36 ODP did not exist when I made the flight I mentioned. I told Center that I could maintain my own terrain and obstruction clearance, and I climbed slightly to the west of the localizer, so as to make sure I stayed over the lake until they had radar contact and could provide vectors.

The ODP has existed there for at least 10 years (the first I saw that airport), but,,,

Fortunately, the ceiling was high enough to avoid the close-in obstacles visually.

which is another technique available to Part 91 operators, but not Part 1##, at least with certain levels of equipment.

BTW, how do you "use the runway you don’t use"?

I guess you mean the extra runway length.

 

[Palmpilot]

...Non-standard climb rates are indicated in the text of an ODP as well. e.g. Big Bear City....

I think one of the reasons people get confused is that the text of the ODP appears under a different heading than the minimums, i.e., "DEPARTURE PROCEDURE" vs. "TAKEOFF MINIMUMS." See the entry for Hollister, for example.



This may be less of an issue at Big Bear, because it tells you to use the charted procedure, which has the climb gradients printed right on the chart.

 

[MauleSkinner]

I think one of the reasons people get confused is that the text of the ODP appears under a different heading than the minimums, i.e., "DEPARTURE PROCEDURE" vs. "TAKEOFF MINIMUMS." See the entry for Hollister, for example.

View attachment 97254

This may be less of an issue at Big Bear, because it tells you to use the charted procedure, which has the climb gradients printed right on the chart.

View attachment 97255

They’re under different headings because they’re different things...the “1200-2 or standard” at Big Bear isn’t a just takeoff minimum, is a part of both. So the other parts of 91.175(f) come into play.

 

[Palmpilot]

The ODP has existed there for at least 10 years (the first I saw that airport), but,,,

The flight I referred to was something like twenty years ago. I know there was one for Rwy 18. I don't remember one for Rwy 36, but if there was one, it's possible that I didn't think it was an option because the winds required taking off from Rwy 18.

 

[Ryan F.]

Pleasant change from my normal impertinence, isn’t it?

Au contraire, your contributions are great!

 

[Palmpilot]

They’re under different headings because they’re different things...the “1200-2 or standard” at Big Bear isn’t a just takeoff minimum, is a part of both. So the other parts of 91.175(f) come into play.

True, but I think people get confused because they have heard that takeoff minimums are not mandatory for most part 91 operations, and when they see the climb gradients listed under takeoff minimums, they may draw the wrong conclusion.

 

[MauleSkinner]

True, but I think people get confused because they have heard that takeoff minimums are not mandatory for most part 91 operations, and when they see the climb gradients listed under takeoff minimums, they may draw the wrong conclusion.

Guess I’d agree with that. But I would suggest that the bigger problem is that it’s more of hand-me-down issue, with generations of instructors not understanding it and/or not ensuring it’s understood by their students, so the responsibility for breaking the chain of ignorance falls to guys like @Ryan F.

...and I don’t intend for “ignorance” to be a derogatory term...it’s simply a lack of knowledge.

 

[Palmpilot]

Guess I’d agree with that. But I would suggest that the bigger problem is that it’s more of hand-me-down issue, with generations of instructors not understanding it and/or not ensuring it’s understood by their students, so the responsibility for breaking the chain of ignorance falls to guys like @Ryan F.

...and I don’t intend for “ignorance” to be a derogatory term...it’s simply a lack of knowledge.

I agree with all of that.