6 ms·

I'm surprised the article doesn't mention the Cessna 182, which also started production in 1956 and is still rolling out of the factory new today. While the ar

I'm surprised the article doesn't mention the Cessna 182, which also started production in 1956 and is still rolling out of the factory new today. While the article extols the virtue of the 172's engine, the fact is that the vast majority of them are running very old designs with carburetors and on Avgas. Avgas still contains lead. These old engines are hugely inefficient and flown incorrectly prone to cracked cylinders. Newer models are fuel injected and there are also a few diesel conversions. All Cessna single engine aircraft now have to undergo supplementary inspections (SIDS), at least in Australia and I think it is the same in the US. I've seen first hand the horrendous amount of corrosion which can hide in a 50 year old aeroplane and not be found until the wings are removed. These SIDS inspections have the potential to ground much of the older 152/172/182 fleet and render what was a $25,000 asset practically worthless. It will be uneconomical to repair in many cases. The above has happened to me personally with a Cessna 182. In the end it was sold for scrap with only the engine and avionics retaining any value. I've also seen the costs of these inspections on a Cessna 210 exceed $20,000. It needed a whole new main wing spar amongst other things. The point I am making is that these very old single engine light aircraft need very meticulous inspections now to ensure they are still safe to fly. I do believe there are probably quite a few seriously at risk aeroplanes still flying today, especially if they have been left outside in coastal areas for any length of time. I used to own a light aeroplane maintenance business.

da02 10y ago
Why did you leave the aeroplane maintenance business? What business did you go into afterwards?
- phillc73 10y ago
  We went broke, for many different reasons. I now work in pharmaceutical engineering R&D, breed thoroughbred horses and mess about with data science.
  - da02 10y ago
    Have you ever known anyone to use hyaluronic acid for old horses?
    - phillc73 10y ago
      Not personally, but I do know it is used for joint pain.
    - chinathrow 10y ago
      It's also used on humans if they have joint issues such as arthrosis.
  - webwalker 10y ago
    As you do...
  - jacquesm 10y ago
    That has to be one of the most interesting career paths that I'm aware of. Impressed with your ability to adapt and learn outside of some narrow envelope.
    - phillc73 10y ago
      Thank you. I've also worked at a major dotcom, starting pre-2000 for all the fun, and in the television industry for a major UK broadcaster. While each industry has required its own knowledge, I have more or less been applying the same set of skills. For example, now in the pharma engineering R&D role, I'm just a project manager rather than a scientist. I read a handful of in-depth papers in my specific area (Optical Coherence Tomography) and by then I could at least understand the technology. I also had just moved to a new country, needed a job and they needed someone with good English and reasonable management skills. The horses and data science interests are linked and the direction where I want things to seriously go next. I'm learning the trade and just starting out now. Or, you could look at my career path and deduce that I just get bored easily....
      - 10y ago
dghughes 10y ago
I did a bit of training in a Cessna 152 but one day we had to take a 172 it was like going from a Yugo to a Cadillac. In the 152 I was literally rubbing shoulders with my instructor but in the 172 we had shoulder room. The 172 has four seats and feels huge compared to the 152, well really it is huge compared to the 152.
- jfroma 10y ago
  I have my baptism flight a month ago in a 152. The instructor was worried because he couldn't fully move the wheel back because of my knees, then I tried another position and he couldn't press the pedals. It took us a while to find a position for my legs, but I didn't feel safe about this until we landed. I am tall 1.90m (6'3"). I want to take classes further but I think I should find another plane. Note: I used a Fiat 600 for like 6 months. I think the 152 is smaller inside.
  - chris_va 10y ago
    I'm about your height, and the 172 works fine. The 152 is definitely a squeeze.
  - simplyluke 10y ago
    Last time I was in the air in a private plane was a 152 a couple of months after a friend achieved his pilot's license. We're both 6'2" and around 190lbs. It took a bit of work, and we were shoulder to shoulder the entire flight, but it was workable. The cabin of the 152 is smaller than any car I've ever been inside of. There's room behind the seats for maybe two backpacks.
  - UhUhUhUh 10y ago
    I have 200 hours in a 150 and I'm your height. You'll get used to it. Keep in mind that the 150/2 is a better training plane than the 172. It will teach you to respect the rudder and the crosswinds, while a 172 is forgiving to the point that it may become dangerous. Also, anxiety is normal initially. I'm saying that because there's a difference of ... 1/4" between the two planes' cabin width (39 1/2 to 39 1/4).
FabHK 10y ago
> flown incorrectly prone to cracked cylinders. How do you avoid that, i.e. "fly correctly"? Do you recommend cylinder temperature gauges?
- phillc73 10y ago
  This would now probably get into the big debate around running these engines rich of peak or lean of peak. Generally, speaking engines of this type are manually leaned - full rich for take off, climb and landing, then leaned for fuel conservation in cruise. The debate is around whether it is better for the engine to be run slightly richer or slightly leaner over an extended period of time. Slightly lean of peak is probably better. However, if leaned too much there is the risk of one or more cylinders overheating. Exhaust Gas Temperature (EGT) guages should be used to monitor this. Many older Cessna 172/182s wouldn't be fitted with EGTs. They certainly weren't factory standard in the 50s, 60s and 70s. All this leaning of mixture is done manually, by turning a knob screw in the cockpit. Another risk is shock cooling. This isn't really an issue with Cessna singles, but can be a real problem with heavier twins like a Piper Chieftain (PA31-350). They easentially run two bigger versions of a very similar engine.
  - sokoloff 10y ago
    When lean of peak, leaner is cooler, so the overheating risk you're describing is generally from cylinders operated "not lean enough" if the intent was to operate lean of peak.
    - gonzo 10y ago
      Well, 50deg LoP is the same EGT as 50deg RoP. But, in general, leaner is hotter, not cooler. At a ROP setting, the extra fuel that is not burned lands on many of the top end components including the exhaust valve. As it evaporates off the surface or out of the fuel/air charge, it cools the component or charge. Also, peak cylinder pressures are higher when run RoP. http://www.gami.com/paulferraris_leanofpeaksaga.pdf http://www.gami.com/paulferraris_leanofpeaksaga.pdf In any case, the Cessna 172S Lycoming IO-360-L2A (engine) handbook says, "Continuous operation at mixture settings lean of peak EGT is prohibited"
bluecmd 10y ago
Here in Sweden it's common to fly on unleaded AVGAS.
- phillc73 10y ago
  Hjelmco is certainly fighting the good fight in that regard. Which brings up the point of the availability of Avgas worldwide. I had an aeroplane ferried from the UK to Australia, via the middle east and asia. Avgas, with engines only certified to use the leaded variety, was extremely hard to find and extremely expensive through much of the region. I have a photo of the aircraft being refuelled in India via hand held funnel and two gallon cans. This also means that many of the NGO and small relief aircraft which used to be active in those areas are no more. Still plenty of JetA1 available, but one needs a totally different engine for that.....
  - Gibbon1 10y ago
    Last time I looked, few years ago it seemed the long term solution was to switch to diesel. Diesel has some advantages, higher efficiency means lower fuel consumption, energy per gallon is higher, but lower per pound. And also diesel is safer to handle. Probably modern materials allow for reliable diesel aircraft engines that are lower cost over the life of the aircraft. But difficult though since the pace of development in the light aircraft industry is very slow and there is little money in it.
    - AshleyGrant 10y ago
      The nice thing with a diesel aviation engine is that it can run on kerosene (Jet fuel). Jet fuel is available at pretty much every airport.
      - Gibbon1 10y ago
        Yeah's the big driver otherwise it'd be moot. I think most everyone that tried introducing diesel aero engines in the early 2000's went bankrupt. Which actually isn't the end of things as long as the business is sound.
burger_moon 10y ago
Shouldn't the leaded fuel make the engine less prone to detonation and cylinder cracking? Also how do you tune carburetors on an airplane? Do you target the cruising altitude of the aircraft or above that altitude maybe?
- debergalis 10y ago
  Yes, the lead raises the effective octane, preventing detonation. The other tool for preventing detonation is running extremely rich fuel/air ratios, the typical setup for the airplane at full takeoff power. You target an appropriately rich mixture at sea level when tuning the carb or adjusting fuel flow for injected engines. The pilot manually leans the mixture as the aircraft climbs to maintain a reasonable fuel/air ratio. Owners sometimes call that mixture lever the money lever because it governs fuel flow, aka "dollars spent per minute".
ImTalking 10y ago
Agreed. I got my PP license 40 years ago on a 172, then 4 years ago went thru training again to renew but quit due to the condition of the planes (all 150's, 172's). I also quit because I realised (maybe because I'm older now), that there is no place for a part-time pilot. Too dangerous. Either you fly every day or don't fly at all because eventually something is going to happen, especially considering the planes I was flying and if you fly 1-2 times a month you are ill-equipped to handle any emergency situation.
- JohnJamesRambo 10y ago
  You made a very mature decision. I wish more people were honest with themselves like you.
- nojvek 10y ago
  I got into skydiving and quit because of the same reason you mention. Certain activities are inheritently dangerous, unless you get regular practice, statistics will eventually cause a fatality someday.
paulmd 10y ago
Does this still apply to (say) Piper Archers?
- phillc73 10y ago
  Not sure which comment you're replying to, but if it's my original post about hidden corrosion, then yes it will apply to all older light aviation types. However, some are potentially more vulnerable than others. A high wing Cessna 172, parked uncovered outside in a coastal area is going to be much worse in many aspects than a low wing Piper Archer, hangared somewhere inland. Here's an FAQ from the Australian regulator. It states that they are in discussion with Beechcraft and Piper regarding SIDS: https://www.casa.gov.au/standard-page/questions-and-comments-cessna-sids https://www.casa.gov.au/standard-page/questions-and-comments...
ctennis1 10y ago
Just to note: SIDS are not required for part 91 operations, at least in the US. If your aircraft is part of a Cessna maintenance program, then it will get lumped in, but for many older aircraft who are privately owned and flown, SIDS are recommended but not required by the FAA..at least not yet.
- phillc73 10y ago
  Right. I am most familiar with the Australian regulatory landscape. CASA has made Cessna SIDS mandatory. https://www.casa.gov.au/standard-page/questions-and-comments-cessna-sids https://www.casa.gov.au/standard-page/questions-and-comments...
cpncrunch 10y ago
>I've seen first hand the horrendous amount of corrosion which can hide in a 50 year old aeroplane and not be found until the wings are removed. If it's such a problem, how come there hasn't been a single case of a in-flight structural failure from corrosion of any strut-braced Cessna? In fact there have only been two cases of structural failure in 172s, both of which appear to have been caused by trying to do aerobatics: https://www.ntsb.gov/about/employment/_layouts/ntsb.aviation/brief.aspx?ev_id=20030123X00096&key=1 https://www.ntsb.gov/about/employment/_layouts/ntsb.aviation... http://aviation-safety.net/wikibase/wiki.php?id=45260 http://aviation-safety.net/wikibase/wiki.php?id=45260
- phillc73 10y ago
  It could be that the SIDS inspections are in place to prevent catastrophic structural failures. One single edition of Flight Safety Australia in 2015 lists five reports of corrosion in Cessna singles, including specifically relating to the main wing spar. http://www.flightsafetyaustralia.com/2015/06/24-march-20-may-2015-7/ http://www.flightsafetyaustralia.com/2015/06/24-march-20-may...

da02 10y ago

Why did you leave the aeroplane maintenance business? What business did you go into afterwards?

phillc73 10y ago
We went broke, for many different reasons. I now work in pharmaceutical engineering R&D, breed thoroughbred horses and mess about with data science.
- da02 10y ago
  Have you ever known anyone to use hyaluronic acid for old horses?
  - phillc73 10y ago
    Not personally, but I do know it is used for joint pain.
  - chinathrow 10y ago
    It's also used on humans if they have joint issues such as arthrosis.
- webwalker 10y ago
  As you do...
- jacquesm 10y ago
  That has to be one of the most interesting career paths that I'm aware of. Impressed with your ability to adapt and learn outside of some narrow envelope.
  - phillc73 10y ago
    Thank you. I've also worked at a major dotcom, starting pre-2000 for all the fun, and in the television industry for a major UK broadcaster. While each industry has required its own knowledge, I have more or less been applying the same set of skills. For example, now in the pharma engineering R&D role, I'm just a project manager rather than a scientist. I read a handful of in-depth papers in my specific area (Optical Coherence Tomography) and by then I could at least understand the technology. I also had just moved to a new country, needed a job and they needed someone with good English and reasonable management skills. The horses and data science interests are linked and the direction where I want things to seriously go next. I'm learning the trade and just starting out now. Or, you could look at my career path and deduce that I just get bored easily....
    - 10y ago

dghughes 10y ago

I did a bit of training in a Cessna 152 but one day we had to take a 172 it was like going from a Yugo to a Cadillac. In the 152 I was literally rubbing shoulders with my instructor but in the 172 we had shoulder room. The 172 has four seats and feels huge compared to the 152, well really it is huge compared to the 152.

jfroma 10y ago
I have my baptism flight a month ago in a 152. The instructor was worried because he couldn't fully move the wheel back because of my knees, then I tried another position and he couldn't press the pedals. It took us a while to find a position for my legs, but I didn't feel safe about this until we landed. I am tall 1.90m (6'3"). I want to take classes further but I think I should find another plane. Note: I used a Fiat 600 for like 6 months. I think the 152 is smaller inside.
- chris_va 10y ago
  I'm about your height, and the 172 works fine. The 152 is definitely a squeeze.
- simplyluke 10y ago
  Last time I was in the air in a private plane was a 152 a couple of months after a friend achieved his pilot's license. We're both 6'2" and around 190lbs. It took a bit of work, and we were shoulder to shoulder the entire flight, but it was workable. The cabin of the 152 is smaller than any car I've ever been inside of. There's room behind the seats for maybe two backpacks.
- UhUhUhUh 10y ago
  I have 200 hours in a 150 and I'm your height. You'll get used to it. Keep in mind that the 150/2 is a better training plane than the 172. It will teach you to respect the rudder and the crosswinds, while a 172 is forgiving to the point that it may become dangerous. Also, anxiety is normal initially. I'm saying that because there's a difference of ... 1/4" between the two planes' cabin width (39 1/2 to 39 1/4).

FabHK 10y ago

> flown incorrectly prone to cracked cylinders. How do you avoid that, i.e. "fly correctly"? Do you recommend cylinder temperature gauges?

phillc73 10y ago
This would now probably get into the big debate around running these engines rich of peak or lean of peak. Generally, speaking engines of this type are manually leaned - full rich for take off, climb and landing, then leaned for fuel conservation in cruise. The debate is around whether it is better for the engine to be run slightly richer or slightly leaner over an extended period of time. Slightly lean of peak is probably better. However, if leaned too much there is the risk of one or more cylinders overheating. Exhaust Gas Temperature (EGT) guages should be used to monitor this. Many older Cessna 172/182s wouldn't be fitted with EGTs. They certainly weren't factory standard in the 50s, 60s and 70s. All this leaning of mixture is done manually, by turning a knob screw in the cockpit. Another risk is shock cooling. This isn't really an issue with Cessna singles, but can be a real problem with heavier twins like a Piper Chieftain (PA31-350). They easentially run two bigger versions of a very similar engine.
- sokoloff 10y ago
  When lean of peak, leaner is cooler, so the overheating risk you're describing is generally from cylinders operated "not lean enough" if the intent was to operate lean of peak.
  - gonzo 10y ago
    Well, 50deg LoP is the same EGT as 50deg RoP. But, in general, leaner is hotter, not cooler. At a ROP setting, the extra fuel that is not burned lands on many of the top end components including the exhaust valve. As it evaporates off the surface or out of the fuel/air charge, it cools the component or charge. Also, peak cylinder pressures are higher when run RoP. http://www.gami.com/paulferraris_leanofpeaksaga.pdf http://www.gami.com/paulferraris_leanofpeaksaga.pdf In any case, the Cessna 172S Lycoming IO-360-L2A (engine) handbook says, "Continuous operation at mixture settings lean of peak EGT is prohibited"

bluecmd 10y ago

Here in Sweden it's common to fly on unleaded AVGAS.

phillc73 10y ago
Hjelmco is certainly fighting the good fight in that regard. Which brings up the point of the availability of Avgas worldwide. I had an aeroplane ferried from the UK to Australia, via the middle east and asia. Avgas, with engines only certified to use the leaded variety, was extremely hard to find and extremely expensive through much of the region. I have a photo of the aircraft being refuelled in India via hand held funnel and two gallon cans. This also means that many of the NGO and small relief aircraft which used to be active in those areas are no more. Still plenty of JetA1 available, but one needs a totally different engine for that.....
- Gibbon1 10y ago
  Last time I looked, few years ago it seemed the long term solution was to switch to diesel. Diesel has some advantages, higher efficiency means lower fuel consumption, energy per gallon is higher, but lower per pound. And also diesel is safer to handle. Probably modern materials allow for reliable diesel aircraft engines that are lower cost over the life of the aircraft. But difficult though since the pace of development in the light aircraft industry is very slow and there is little money in it.
  - AshleyGrant 10y ago
    The nice thing with a diesel aviation engine is that it can run on kerosene (Jet fuel). Jet fuel is available at pretty much every airport.
    - Gibbon1 10y ago
      Yeah's the big driver otherwise it'd be moot. I think most everyone that tried introducing diesel aero engines in the early 2000's went bankrupt. Which actually isn't the end of things as long as the business is sound.

burger_moon 10y ago

Shouldn't the leaded fuel make the engine less prone to detonation and cylinder cracking? Also how do you tune carburetors on an airplane? Do you target the cruising altitude of the aircraft or above that altitude maybe?

debergalis 10y ago
Yes, the lead raises the effective octane, preventing detonation. The other tool for preventing detonation is running extremely rich fuel/air ratios, the typical setup for the airplane at full takeoff power. You target an appropriately rich mixture at sea level when tuning the carb or adjusting fuel flow for injected engines. The pilot manually leans the mixture as the aircraft climbs to maintain a reasonable fuel/air ratio. Owners sometimes call that mixture lever the money lever because it governs fuel flow, aka "dollars spent per minute".

ImTalking 10y ago

Agreed. I got my PP license 40 years ago on a 172, then 4 years ago went thru training again to renew but quit due to the condition of the planes (all 150's, 172's). I also quit because I realised (maybe because I'm older now), that there is no place for a part-time pilot. Too dangerous. Either you fly every day or don't fly at all because eventually something is going to happen, especially considering the planes I was flying and if you fly 1-2 times a month you are ill-equipped to handle any emergency situation.

JohnJamesRambo 10y ago
You made a very mature decision. I wish more people were honest with themselves like you.
nojvek 10y ago
I got into skydiving and quit because of the same reason you mention. Certain activities are inheritently dangerous, unless you get regular practice, statistics will eventually cause a fatality someday.

paulmd 10y ago

Does this still apply to (say) Piper Archers?

phillc73 10y ago
Not sure which comment you're replying to, but if it's my original post about hidden corrosion, then yes it will apply to all older light aviation types. However, some are potentially more vulnerable than others. A high wing Cessna 172, parked uncovered outside in a coastal area is going to be much worse in many aspects than a low wing Piper Archer, hangared somewhere inland. Here's an FAQ from the Australian regulator. It states that they are in discussion with Beechcraft and Piper regarding SIDS: https://www.casa.gov.au/standard-page/questions-and-comments-cessna-sids https://www.casa.gov.au/standard-page/questions-and-comments...

ctennis1 10y ago

Just to note: SIDS are not required for part 91 operations, at least in the US. If your aircraft is part of a Cessna maintenance program, then it will get lumped in, but for many older aircraft who are privately owned and flown, SIDS are recommended but not required by the FAA..at least not yet.

phillc73 10y ago
Right. I am most familiar with the Australian regulatory landscape. CASA has made Cessna SIDS mandatory. https://www.casa.gov.au/standard-page/questions-and-comments-cessna-sids https://www.casa.gov.au/standard-page/questions-and-comments...

cpncrunch 10y ago

>I've seen first hand the horrendous amount of corrosion which can hide in a 50 year old aeroplane and not be found until the wings are removed. If it's such a problem, how come there hasn't been a single case of a in-flight structural failure from corrosion of any strut-braced Cessna? In fact there have only been two cases of structural failure in 172s, both of which appear to have been caused by trying to do aerobatics: https://www.ntsb.gov/about/employment/_layouts/ntsb.aviation/brief.aspx?ev_id=20030123X00096&key=1 https://www.ntsb.gov/about/employment/_layouts/ntsb.aviation... http://aviation-safety.net/wikibase/wiki.php?id=45260 http://aviation-safety.net/wikibase/wiki.php?id=45260

phillc73 10y ago
It could be that the SIDS inspections are in place to prevent catastrophic structural failures. One single edition of Flight Safety Australia in 2015 lists five reports of corrosion in Cessna singles, including specifically relating to the main wing spar. http://www.flightsafetyaustralia.com/2015/06/24-march-20-may-2015-7/ http://www.flightsafetyaustralia.com/2015/06/24-march-20-may...