What would you do? (Checkride)

Fly4Fun! said:
PA28R is completely capable. The issue is proving performance with a lack of information. I could look at the DPE and say, "I've done it before and it worked out". I do not believe the response from my DPE would be pleasant.
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I bet if you had nice chart you have developed, like a commercial operator would probably do for their 135 operations Manual, and showed him that you and the airplane were capable and had demonstrated that you could safely depart with adequate margins that it would not be an unpleasant conversation at all.

Brian
 
Fly4Fun! said:
PA28R is completely capable. The issue is proving performance with a lack of information. I could look at the DPE and say, "I've done it before and it worked out". I do not believe the response from my DPE would be pleasant.
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Why would you think it would not be pleasant? You've flown out of this airport before at similar weights and temperatures and had no issues, correct?
 
Fly4Fun! said:
PA28R is completely capable. The issue is proving performance with a lack of information. I could look at the DPE and say, "I've done it before and it worked out". I do not believe the response from my DPE would be pleasant.
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How about, “I’ve taken off at this weight under similar conditions, and my takeoff ground roll was consistently between 1900 and 2000 feet.”
 
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Fly4Fun! said:
I have my commercial checkride next week. I have been studying my butt off... I finally feel up to the ACS standards on both the ground and flight portion.

However, I have an issue:

The aircraft I am taking my checkride in is an old Piper Arrow. The AFM only offers one chart for takeoff performance, which is max gross. With a 1.5 margin, at max gross, with temperatures that are most likely for an august afternoon, I am not safely clearing a 50 foot obstacles.

With all that said, the situation I have been provided by my DPE doesn't have us departing at max gross. On top of that, I do not nearly need full tanks.

I know about the 30/70 rule for obstacles, and the 50/70 rule for takeoffs without an obstacle, but those are rules of thumbs to back up know performance numbers.

I believe that the correct answer is that in the interest of safety, only the know performance numbers can be utilized, and that a departure with the given conditions (HOT) is unsafe. Departing bellow max gross will have a resultant increase in performance, however how much of an increase is a guess, which is (in my opinion) an unacceptable level of risk.

Am I looking at this wrong?
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What would you do with a paying customer onboard? What would be the safest thing to do PIC?

The limited data you have is all you can use. Engineering your own data is flying outside the aircraft’s performance envelope. Be prepared to discuss all the factors that would increase or reduce the chart values, but don’t stray from the chart. If you need a longer runway for the demo, go there. You are the PIC. You will not be flunked for the minimums you set and can explain.
 
What serial number is your Arrow? You can find it using the registration number on the FAA website.

See: https://www.manualslib.com/download/1300461/Piper-Cherokee-Arrow-200.html

This handbook for airplanes with
serial nos. 28R-35001 through 28R-35392.

Free download, if you have problems let me know and I'll send it to you.

The take off performance chart shows about 1800' to clear a 50' obstacle at 1500' DA flaps 25.
 
Fly4Fun! said:
I have my commercial checkride next week. I have been studying my butt off... I finally feel up to the ACS standards on both the ground and flight portion.

However, I have an issue:

The aircraft I am taking my checkride in is an old Piper Arrow. The AFM only offers one chart for takeoff performance, which is max gross. With a 1.5 margin, at max gross, with temperatures that are most likely for an august afternoon, I am not safely clearing a 50 foot obstacles.

With all that said, the situation I have been provided by my DPE doesn't have us departing at max gross. On top of that, I do not nearly need full tanks.

I know about the 30/70 rule for obstacles, and the 50/70 rule for takeoffs without an obstacle, but those are rules of thumbs to back up know performance numbers.

I believe that the correct answer is that in the interest of safety, only the know performance numbers can be utilized, and that a departure with the given conditions (HOT) is unsafe. Departing bellow max gross will have a resultant increase in performance, however how much of an increase is a guess, which is (in my opinion) an unacceptable level of risk.

Am I looking at this wrong?
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If this were not a checkride but a regular flight with a passenger, would you still fly?
 
Fly4Fun! said:
...With a 1.5 margin, the aircraft will require 2451 feet (safely).

Is this flawed? I feel it would behoove me not to bring up unknown numbers.
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It seems to me that those two sentences contradict one another. By "1.5 margin," I assume you're saying that you're adding 50% to the book number. However, that's not a legal requirement as far as I know. So in effect, you're using a fudge factor when it penalizes yourself, but not when it helps you.

Now I would agree that assuming you're going to achieve the exact book numbers is generally not wise, but it seems to me that's a confidence-level issue, not a legal issue. So I would say "Use the unpadded book numbers to determine legality, but use the 50% margin in combination with your gross-weight-related estimate to determine your confidence level."

(No special expertise here, just an opinion from SGOTI.)
 
Palmpilot said:
It seems to me that those two sentences contradict one another. By "1.5 margin," I assume you're saying that you're adding 50% to the book number. However, that's not a legal requirement as far as I know. So in effect, you're using a fudge factor when it penalizes yourself, but not when it helps you.

Now I would agree that assuming you're going to achieve the exact book numbers is generally not wise, but it seems to me that's a confidence-level issue, not a legal issue. So I would say "Use the unpadded book numbers to determine legality, but use the 50% margin in combination with your gross-weight-related estimate to determine your confidence level."

(No special expertise here, just an opinion from SGOTI.)
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This is an interesting point. It is my experience that those who employ professional pilots expect flight when it is legal. You can't very often get away with saying "well this is legal but it is below my personal minimums so I won't do it."
 
My previous post (76) was in reference to Ed Fred's post 62, where the only thing that changed was gross weight (from 2400 to 2000 lbs). My answer (1667 feet to clear a 50' obstacle) was called "rudimentary". So what is the correct number using his information?
 
Arnold said:
This is an interesting point. It is my experience that those who employ professional pilots expect flight when it is legal. You can't very often get away with saying "well this is legal but it is below my personal minimums so I won't do it."
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I think people expect professionals to incorporate a reasonable margin for error.

I also wouldn't be surprised if Part 135 and Part 121 included required margins. :dunno:
 
Palmpilot said:
I think people expect professionals to incorporate a reasonable margin for error.

I also wouldn't be surprised if Part 135 and Part 121 included required margins. :dunno:
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The regs themselves don’t, for the most part.
 
I would not go to a checkride showing fancy math that the DPE May not understand. He is putting his life on that.
 
I am getting ready to do my commercial checkride as well. My plane is so modified, there are no performance charts. Can you not just use a hypothetical?
 
Wagondriver said:
I am getting ready to do my commercial checkride as well. My plane is so modified, there are no performance charts. Can you not just use a hypothetical?
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Is there no FAA-approved documentation associated with the mods?
 
Palmpilot said:
Is there no FAA-approved documentation associated with the mods?
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Original O-470A replaced with PPonk o520, sportsman leading edge cuff, those two alone change everything.
But, no, I do not have a performance chart combining extra HP and different wing.
 
Wagondriver said:
I am getting ready to do my commercial checkride as well. My plane is so modified, there are no performance charts. Can you not just use a hypothetical?
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How reliable is your hypothetical?
Per the reg…”other reliable information appropriate to the aircraft,”
 
hypothetical with a known airplane. Like say a stock 180.
I know my airplane well, but even if I have a few hundred hours in it and a very good idea of what I can get into and out of, I don't have a chart to back it up when if I tell the DPE that I will use 900' of runway at DA of 11,000'.
 
Wagondriver said:
hypothetical with a known airplane. Like say a stock 180.
I know my airplane well, but even if I have a few hundred hours in it and a very good idea of what I can get into and out of, I don't have a chart to back it up when if I tell the DPE that I will use 900' of runway at DA of 11,000'.
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Why do you need a chart? Are you not reliable?

I assume your first takeoff in the checkride isn’t going to be from a 900 foot strip at an 11,000 foot DA. Do a takeoff wherever you’re at, and use a Koch chart to adjust for density altitude.

do stock 180 charts even go to 11,000 feet?
 
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I have never seen a performance chart that said that you had to use 1.5 margin on the numbers in the chart. While I agree that your average plane flown by your average pilot may not get the numbers shown in the chart, I have yet to pilot so poorly or have a plane fly so much under the numbers that I had to add 150% to the performance chart. Where are you getting that 150%? Is this something that the DPE has added to the scenario or are you using some rule of thumb for added safety that has nothing to do with the actual regulations or the ACS? If it's your own personal minimums or rule of thumb, I would be ready to show the DPE the numbers that the performance chart suggest and then explain what margins that you use as personal minimums and what actions that you could take to make it a safer flight (less fuel, reduce baggage, depart under different weather conditions, etc). It's pretty common for a DPE to give you a scenario for the checkride where a flight may be at the edge of the airplane's capabilities to set up for the risk management discussion, but I've never heard of a DPE that insists on a fudge factor of +50% on the performance charts.

The most important part of that paragraph is this: "Where are you getting that 150%?"
 
redhounds said:
I have never seen a performance chart that said that you had to use 1.5 margin on the numbers in the chart. While I agree that your average plane flown by your average pilot may not get the numbers shown in the chart, I have yet to pilot so poorly or have a plane fly so much under the numbers that I had to add 150% to the performance chart. Where are you getting that 150%? Is this something that the DPE has added to the scenario or are you using some rule of thumb for added safety that has nothing to do with the actual regulations or the ACS? If it's your own personal minimums or rule of thumb, I would be ready to show the DPE the numbers that the performance chart suggest and then explain what margins that you use as personal minimums and what actions that you could take to make it a safer flight (less fuel, reduce baggage, depart under different weather conditions, etc). It's pretty common for a DPE to give you a scenario for the checkride where a flight may be at the edge of the airplane's capabilities to set up for the risk management discussion, but I've never heard of a DPE that insists on a fudge factor of +50% on the performance charts.

The most important part of that paragraph is this: "Where are you getting that 150%?"
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150% is a number that’s been thrown around for a long time…40 years ago is when I first heard it. I think I may have seen it in an FAA pamphlet years ago, as well.

And yes, I’ve seen actual takeoffs and landings that exceeded the 150% number that the pilot claimed as a “safety factor” numerous times.
 
redhounds said:
I have never seen a performance chart that said that you had to use 1.5 margin on the numbers in the chart. While I agree that your average plane flown by your average pilot may not get the numbers shown in the chart, I have yet to pilot so poorly or have a plane fly so much under the numbers that I had to add 150% to the performance chart. Where are you getting that 150%? Is this something that the DPE has added to the scenario or are you using some rule of thumb for added safety that has nothing to do with the actual regulations or the ACS? If it's your own personal minimums or rule of thumb, I would be ready to show the DPE the numbers that the performance chart suggest and then explain what margins that you use as personal minimums and what actions that you could take to make it a safer flight (less fuel, reduce baggage, depart under different weather conditions, etc). It's pretty common for a DPE to give you a scenario for the checkride where a flight may be at the edge of the airplane's capabilities to set up for the risk management discussion, but I've never heard of a DPE that insists on a fudge factor of +50% on the performance charts.

The most important part of that paragraph is this: "Where are you getting that 150%?"
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Seems to me this is a "drift down" from 135/121 which specify take-off and landing distance margins.
 
Arnold said:
Seems to me this is a "drift down" from 135/121 which specify take-off and landing distance margins.
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Which oddly enough specifies landing margins as a takeoff requirement, not a landing requirement.
 
I've only been flying for 20 years, but I've never seen anything regulatory or in the PTS or ACS that requires a 150% fudge factor, which is why I'm asking if the DPE has required that or if it's just a rule of thumb number. If it's the rule of thumb that you're referring too, then it's certainly important to add it to the discussion, but it shouldn't automatically mean that any flight that can't make the 1.5 margin should be a no-go.
 
MauleSkinner said:
Which oddly enough specifies landing margins as a takeoff requirement, not a landing requirement.
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About a year ago I was speaking with an FAA inspector who was upset that a pilot had landed with less than reserve fuel. I had to point out that reserve fuel is a take-off requirement and that was the only way it made any sense.
 
redhounds said:
I've only been flying for 20 years, but I've never seen anything regulatory or in the PTS or ACS that requires a 150% fudge factor, which is why I'm asking if the DPE has required that or if it's just a rule of thumb number. If it's the rule of thumb that you're referring too, then it's certainly important to add it to the discussion, but it shouldn't automatically mean that any flight that can't make the 1.5 margin should be a no-go.
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Not regulatory. [Edit] Part 91.
 
I didn't realize that 135/121 had 150% as a margin of safety. That makes sense.
 
Arnold said:
About a year ago I was speaking with an FAA inspector who was upset that a pilot had landed with less than reserve fuel. I had to point out that reserve fuel is a take-off requirement and that was the only way it made any sense.
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VFR reserves are specified in the reg as a takeoff requirement.

IFR reserves are required in flight when in “IFR conditions”.
 
MauleSkinner said:
VFR reserves are specified in the reg as a takeoff requirement.

IFR reserves are required in flight when in “IFR conditions”.
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I guess that would mean that using your reserve fuel in IFR conditions would constitute an emergency.
 
redhounds said:
Out of curiosity, which part is wrong: that they don't have a margin of safety in their op specs or that they don't have 150% as the margin of safety?
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The 135 regs require that certain airplanes, for planning purposes, be able to land within 60 or 70 percent of the runway available, with some other factors thrown in for non-dry runways and low visibility. Most of those requirements go away as soon as the airplane takes off.
 
MauleSkinner said:
VFR reserves are specified in the reg as a takeoff requirement.

IFR reserves are required in flight when in “IFR conditions”.
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Ah regulatory consistency - wherefore art thou?

§ 91.167 Fuel requirements for flight in IFR conditions.
(a) No person may operate a civil aircraft in IFR conditions unless it carries enough fuel (considering weather reports and forecasts and weather conditions) to -

91.1 IFR conditions means weather conditions below the minimum for flight under visual flight rules.


§ 91.151 Fuel requirements for flight in VFR conditions.
(a) No person may begin a flight in an airplane under VFR conditions unless (considering wind and forecast weather conditions) there is enough fuel to fly to the first point of intended landing and, assuming normal cruising speed -

(1) During the day, to fly after that for at least 30 minutes; or

(2) At night, to fly after that for at least 45 minutes.

91.1 VFR means visual flight rules.

See: https://www.law.cornell.edu/cfr/text/14/part-91/subpart-B

The phrase "IFR conditions" is defined. The acronym "VFR" is defined. The phrase "VFR conditions" is not defined.

So for the sake of legal nitpicking. What is the fuel reserve requirement for a pilot operating on an IFR flight plan in VFR conditions? I could argue that it is less than the fuel reserve requirement for operating VFR in VFR conditions.

Example. You have 30 minutes fuel in the ship. You want to fly from A to B ins VMC conditions. Flight time is expected to be 15 minutes. Are you legal to fly day VFR from A to B? No.
Are you legal to fly IFR from A to B IFR? Yes.

Is this careless and reckless (91.13(a))? Perhaps.
 
Arnold said:
Ah regulatory consistency - wherefore art thou?

§ 91.167 Fuel requirements for flight in IFR conditions.
(a) No person may operate a civil aircraft in IFR conditions unless it carries enough fuel (considering weather reports and forecasts and weather conditions) to -

91.1 IFR conditions means weather conditions below the minimum for flight under visual flight rules.


§ 91.151 Fuel requirements for flight in VFR conditions.
(a) No person may begin a flight in an airplane under VFR conditions unless (considering wind and forecast weather conditions) there is enough fuel to fly to the first point of intended landing and, assuming normal cruising speed -

(1) During the day, to fly after that for at least 30 minutes; or

(2) At night, to fly after that for at least 45 minutes.

91.1 VFR means visual flight rules.

See: https://www.law.cornell.edu/cfr/text/14/part-91/subpart-B

The phrase "IFR conditions" is defined. The acronym "VFR" is defined. The phrase "VFR conditions" is not defined.

So for the sake of legal nitpicking. What is the fuel reserve requirement for a pilot operating on an IFR flight plan in VFR conditions? I could argue that it is less than the fuel reserve requirement for operating VFR in VFR conditions.

Example. You have 30 minutes fuel in the ship. You want to fly from A to B ins VMC conditions. Flight time is expected to be 15 minutes. Are you legal to fly day VFR from A to B? No.
Are you legal to fly IFR from A to B IFR? Yes.

Is this careless and reckless (91.13(a))? Perhaps.
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I would say that just as VFR on top is both IFR and VFR, that operating in wx in accordance with 91.155, are operating under VFR and IFR. So you would still need the 30 minutes, or 45 at night.

If you aren't in IFR conditions, you are in default VFR conditions. And unless class A you are still required to see and avoid, so still bound by VFR rules as well (altitudes not included)
 
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