presolo exam help. question on fuel consumption

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jconway2002

Pre-takeoff checklist
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jconway2002
Hello,

I am stuck on this question, and could use any help on how to get the correct answer.

On a standard day (sea level temperature, 59*F, altimeter 29.92 in. Hg.), the fuel consumption rate during normal (approximately 75% power) cruise is ___ gallons per hour.

Thanks for any help.
 
jconway2002 said:
Hello,

I am stuck on this question, and could use any help on how to get the correct answer.

On a standard day (sea level temperature, 59*F, altimeter 29.92 in. Hg.), the fuel consumption rate during normal (approximately 75% power) cruise is ___
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found in the aircraft handbook.

(and different for every aircraft - I could tell you mine is 4.5 GPH, but that wouldn't help you.)
 
jconway2002 said:
Hello,

I am stuck on this question, and could use any help on how to get the correct answer.

On a standard day (sea level temperature, 59*F, altimeter 29.92 in. Hg.), the fuel consumption rate during normal (approximately 75% power) cruise is ___ gallons per hour.

Thanks for any help.
Click to expand...

Time to dig out the POH
 
jconway2002 said:
Hello,

I am stuck on this question, and could use any help on how to get the correct answer.

On a standard day (sea level temperature, 59*F, altimeter 29.92 in. Hg.), the fuel consumption rate during normal (approximately 75% power) cruise is ___ gallons per hour.

Thanks for any help.
Click to expand...

The performance charts from the POH/AFM is where you find that, look for the ones labeled 'Fuel Consumption'.
 
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I have the Cessna 152 information manual, but so far havent found what I am looking for. All I am seeing is a chart "time, fuel, and distance to climb", but i dont need to know the fuel burned while climbing.
 
EppyGA said:
Time to dig out the POH
Click to expand...

LOL, You getting the picture?:rofl: The point is that is the entire intent of this exercise is to make sure you know where to find the information. Oh, as an aside, this modus operendai is repeated by the DE on your oral. They'll start into a line of questions of increasing complexity and/or obscurity until you have to go find the info. If you know the first 3, you're golden, any time after that you can go to reference no worries, even 2 here and there get you by as long as you have the reference. The closer/faster you can get to that one the better though. One warning, NEVER try and BS the DE,:nono::no: ; admit you don't know, if you can't come up with anything express curiosity, "Wow, I hadn't even thought of that... how...?". You can do that 2-3 times (some DEs more even, you gotta feel em out, too many and most will start getting leary about your competence) through the course of things to eat a total of 20 to 40 minutes of them teaching.
 
Depends entirely on the aircraft. I'm assuming this is the CFI's pre-solo quiz. So go get the POH of the airplane you usually fly and look at the chapter on performance.
 
jconway2002 said:
Hello,

I am stuck on this question, and could use any help on how to get the correct answer.

On a standard day (sea level temperature, 59*F, altimeter 29.92 in. Hg.), the fuel consumption rate during normal (approximately 75% power) cruise is ___ gallons per hour.

Thanks for any help.
Click to expand...

Cessna 152 POH, Chapter 5, Performance. Go read it. The answer is right there, assuming you have a real POH and not one that the school invented. Understand how to correct for temperature and altitude while you're at it.
 
jconway2002 said:
I have the Cessna 152 information manual, but so far havent found what I am looking for. All I am seeing is a chart "time, fuel, and distance to climb", but i dont need to know the fuel burned while climbing.
Click to expand...
Turn a few more pages.
 
jconway2002 said:
I have the Cessna 152 information manual, but so far havent found what I am looking for. All I am seeing is a chart "time, fuel, and distance to climb", but i dont need to know the fuel burned while climbing.
Click to expand...

LOL, keep going, you got charts out the ying yang to learn about; the pre solo exam is to make sure you find the ones you need at this point.
 
"....divide by the cube root of the aircraft's N-number, add the product of the runway length and runway witdth, subtract the height (in centimeters) of your CFI..."
 
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jconway2002 said:
I have the Cessna 152 information manual, but so far havent found what I am looking for. All I am seeing is a chart "time, fuel, and distance to climb", but i dont need to know the fuel burned while climbing.
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In my C172S Flight Manual (the generic version of the POH that lives in the aircraft), the "Cruise Performance" Table is right after the "Time, Fuel, and Distance to Climb" table.

Double check you're not missing a page.
 
denverpilot said:
In Cessna manuals, this will almost always be found in a table or tables titled "Cruise Performance" in Section 5.

Someone brought up the possibility your PIM has pages missing. Here's a link to a 1980 Cessna 152 PIM zipped in PDF format.

http://www.askacfi.com/762/cessna-152-poh.htm
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If there are pages missing, then this is part of the learning assignment to recognize it, and find out why. If an incomplete PIM or POH, then the required paperwork is incomplete, and the aircraft is not airworthy....yeah yeah yeah. Airplane won't fly, same argument as no flight plan...
 
I reckon the fuel burn is in the neighborhood of 6.5-7.0 gph. Just a random guess based on my knowledge of the 172R.

My presolo exam required me to interpolate some data. It took a minute to figure out how to do it, but once you do it three or four times, you should be able to do it swiftly.

Anyway, my guess is that you probably saw the answer six times already but haven't realized it. I did the same thing.
 
A PIM is NEVER a required document.
Pistol...he's flying a 152. The fuel burn isn't likely to be above the low 6's.
 
flyingron said:
A PIM is NEVER a required document.
Pistol...he's flying a 152. The fuel burn isn't likely to be above the low 6's.
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Ok, but the info the OP needs is in the C152 POH, and that is required. And as pointed out, the difference between a PIM and the POH is the legal weight & balance and other items specific to the serial number of the aircraft such as a different engine than originaly specified in the TCDS.

Let me amend my original statement. If there are pages missing from the aircraft POH, then it's not legal to fly.
 
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Thank you everyone for the replies. The pdf of the POH will be very helpful to have electronically.

I am stuck on how to convert an altimeter setting to altitude. Any help here?
 
jconway2002 said:
Thank you everyone for the replies. The pdf of the POH will be very helpful to have electronically.

I am stuck on how to convert an altimeter setting to altitude. Any help here?
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Time to hit the ground school books. You do have some kind of ground school books, course, etc don't you?
 
Meteorological conditions change the pressure outside.. it can be higher or lower depending on the weather at your locality.

The altimeter works by reading atmospheric pressure. When you ascend, the pressure drops and the altimeter reads this drop to you as an increase in height. If the pressure changes willy nilly with the weather, how can the altimeter be accurate? You must adjust the altimeter to the current meteorological conditions, because the natural changes in pressure occuring with weather systems can make the altimeter read higher or lower than you actually are. When you receive an altimeter setting and dial it in to your altimeter, it corrects your altimeter to the local weather conditions and enables the altimeter to display your height correctly.

Its also worth mentioning that since we fly airplanes that can cover long distances quickly, we are always flying through areas of differing pressure and need to periodically adjust the altimeter to keep it accurate.
 
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So...

I found my airports elevation = 331'

I found that if my altimeter reads 29.52 than I should add 400' to my elevation

This gives me a total of 731'

Am I doing this correct? If so, than is it acceptable to calculate the answer by rounding up to 1000' or do they want me to be right on the money?
 
jconway2002 said:
I am stuck on how to convert an altimeter setting to altitude. Any help here?
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Beats me, I have a commercial ticket, 20+ years and 2000+hrs and I don't know how to do that. Altimeter setting only calibrates the altimeter reading for local pressure. Only excess lift converts to altitude.
 
In my experience with taking tests for ground school, the exam should give you a table with various corrections to altitude depending on the setting:

29.8 = -50ft
29.92 = no correction
30.0 = +50ft

Since the altimeter can't really give you an accurate reading unless the Kollsman Window reads the current barometric pressure, simply calculating the altitude from an arbitrary pressure reading seems impossible.

I reckon there's a table on the exam that'll help you!

Edit: I'm not sure if I'm going the right way with my example, so please excuse that.
 
On rounding, always round towards safety. So, for altitudes at take-off, round up to a higher altitude because ground roll and climb performance suffer. For fuel burn, likewise round up, because sure as heck, a 30 year old engine is going to burn more fuel for less power.
 
If my airplane at 75% power at sea level flies at 100 KTAS, than can someone tell me if the answer to my original question is 6.1 GPH?

On a standard day (sea level temperature, 59*F, altimeter 29.92 in. Hg.), the fuel consumption rate during normal (approximately 75% power) cruise is ___ gallons per hour.
 
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jconway2002 said:
Found this resource. Spells it out pretty clearly. Might be useful for someone else in my situation.

http://www.langleyflyingschool.com/Pages/Flight%20Operations--Pressure%20and%20Density%20Altitude.html
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That is a dangerously stupid article. It's not even the correct simplification of the density altitude. The simplified correction is 120 times the difference between the actual temperature and the ISA temperature NOT 100. Even that is an incredibly bad simplification.
 
A quick message to the OP. it's clear that you've not really received or undertaken adequate "ground school" training by the nature of your questions. I might suggest you are not ready to solo.

My experience (by my choice) was to completely understand the book side of the training before seriously starting instruction. I had taken and passed my FAA knowledge exam before solo.

That may be overkill but you will know these sorts of things. Did you have the opportunity to take a formal ground school class? Are you doing self study? Or did your instructor just leave you to figure it out?
 
On the altimeter issue, it might be better if you read us the actual question, as you may be misunderstanding what it's asking for.

But I agree with others that your academic/groundschool prep seems to be lacking at the moment.
 
Doggtyred said:
A quick message to the OP. it's clear that you've not really received or undertaken adequate "ground school" training by the nature of your questions. I might suggest you are not ready to solo.

My experience (by my choice) was to completely understand the book side of the training before seriously starting instruction. I had taken and passed my FAA knowledge exam before solo.

That may be overkill but you will know these sorts of things. Did you have the opportunity to take a formal ground school class? Are you doing self study? Or did your instructor just leave you to figure it out?
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My instructor has pretty much made no mention of ground school to me. On my own I was able to find a syllabus that seemed to coincide with my lessons, and have been using that to read the related chapters in the PHAK, Jepp Manual, and AFH. Before receiving my presolo exam I have never looked at the FAR/AIM or POH for the Cessna 152.
 
jconway2002 said:
My instructor has pretty much made no mention of ground school to me. On my own I was able to find a syllabus that seemed to coincide with my lessons, and have been using that to read the related chapters in the PHAK, Jepp Manual, and AFH. Before receiving my presolo exam I have never looked at the FAR/AIM or POH for the Cessna 152.
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Your instructor has failed to properly prepare you. He should have shown you where to find all this information and reviewed all of these things with you by the point he hands you the presolo quiz. This quiz is meant to provide a review and a written proof of training of the presolo requirements.
 
The answer is 6.1 gph. Notice the fuel burned at 75% power is 6.1 at all altitudes
 
dell30rb said:
The answer is 6.1 gph. Notice the fuel burned at 75% power is 6.1 at all altitudes
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Thanks for confirming I had the right answer. Upon further examination, I found my 152 manual lists different GPH than the one given to me online. My manual shows 6.3 GPH at 2000, and 6.4 at 4000-8000.
 
B
jconway2002 said:
If my airplane at 75% power at sea level flies at 100 KTAS, than can someone tell me if the answer to my original question is 6.1 GPH?

On a standard day (sea level temperature, 59*F, altimeter 29.92 in. Hg.), the fuel consumption rate during normal (approximately 75% power) cruise is ___ gallons per hour.
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No because we don't know the published specs for that airplane as per the POH.

There's a reason there are so many books for ground school material - Jeppesen, ASA, Gleim, King, and the free ones from the FAA website.

Let me strongly suggest you download "Pilots Handbook of Aeronautical Knowledge" FAA 8083-25A.

Then there's Aviation Weather Services FAA AC 00-45F

Both of these are found at
http://www.faa.gov/regulations_policies/handbooks_manuals/

Practical Test Standards, Private FAA-S-8081-14(A or B which will be legal June 2012)
http://www.faa.gov/training_testing/testing/airmen/test_standards/pilot/
 
jconway2002 said:
My instructor has pretty much made no mention of ground school to me. On my own I was able to find a syllabus that seemed to coincide with my lessons, and have been using that to read the related chapters in the PHAK, Jepp Manual, and AFH. Before receiving my presolo exam I have never looked at the FAR/AIM or POH for the Cessna 152.
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Why not?

It appears that your instructor is deficient in preparing you for 1) solo and 2) checkride.

Kudos to you for realizing there's much more you need to learn.
 
jconway2002 said:
My instructor has pretty much made no mention of ground school to me. On my own I was able to find a syllabus that seemed to coincide with my lessons, and have been using that to read the related chapters in the PHAK, Jepp Manual, and AFH. Before receiving my presolo exam I have never looked at the FAR/AIM or POH for the Cessna 152.
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I find this sad and infuriating at the same time. An instructor should be teaching you the aeronautical knowledge you need to be a safe and proficient aviator, not just going along for the flying portion and keeping you from injury while you teach yourself how to fly.

If you're not getting aero knowledge on a regular basis from your instructor, you're doing yourself a disservice.

For all you students out there, the next time the weather is poor, go to the airport anyway, and spend some time on knowledge subjects with your CFI. The airport is a much better classroom than the airplane for those subjects.
 
TMetzinger said:
For all you students out there, the next time the weather is poor, go to the airport anyway, and spend some time on knowledge subjects with your CFI. The airport is a much better classroom than the airplane for those subjects.
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And way less expensive.

To the OP. If your instructor is not following a written syllabus that provides for both adequate knowledge instruction and skills instruction, you are in danger of wasting quite a bit of money.

The money clock will run, he will charge you the hourly rate, regardless of the quality of the information.

If that quality is poor, then it will take more time for you to be presented, acquire, and then sufficiently retain the knowledge for you to pass the written, oral, and practical examinations. Time being money, you need to seriously measure the depth of your pockets or bank account before you continue.

There are several good written syllabi out there that will fill the bill if the instructor doesn't already have one. So discuss the issue with him and give him a chance. If he doesn't change his style, or is unwilling to, consider a different instructor who is more organized and ready to do a better job.
 
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