Part 135/121 operations during extreme temps

UAL747400

Well-Known Member
I'm a "time and place" guy, a wearer of many hats so to speak. I fly/drive/drink/talk/ect. differently depending on the time and place. Part 91, middle of no where, I'm going to worry less about what's legal and more about what CAN be done using careful and realistic judgement. Knowing what I know about C172s and 210s, short of the wings falling off, it's going to fly no matter what. Frost, ice, snow, high density alt with along runway; it doesn't matter. I say that with a little bit of sarcasm. Like I said, I prefer to be legal as well, but I guess I take a more realistic approach. I mean, at FLX, we don't have MELs, EVERYTHING is supposed to work. I'm not writing an airplane up for a post light. This, by the book, is illegal, but I don't give a rats poop hole that I can't read the hobbs in flight. Call me dangerous I guess...

On a race track/auto-cross, I drive like a maniac. You'll find my car spinning wildly through ALL the cones or stuck in the kitty litter short of hitting a wall. In public, I'm slow, cautious Grandpa McGrandpa pants. At a house party, you'll catch me sleeping in the yard the next morning. At a bar, 2 drinks max. ect. ect.
 

Nark

Sheepdog
I lied to you all, the max temp for takeoff and landing is 52C.
-22C for battery start.
-40C for takeoff and -52C for operations.

This is for the jumbo jungle jet.
 

rframe

pǝʇɹǝʌuı
There's a bit of straw man going on here. I dont think anybody claimed airplanes are going to fall out of the sky or spontaneously combust just because you fly them when it's warmer than the published performance specifications. What we said was that it is not legal and you are operating outside of the published performance envelope for that airplane.


The comparison to Experimentals is ridiculous...anybody ever notice the giant placard that reads "EXPERIMENTAL" and the passenger warning "this aircraft is amateur built and does not comply with federal safety regulations"....?

The meat of the question was legality.

I had this almost exact discussion with a FSDO inspector. I asked what exactly do they look for in regards to FAR 91.103, since it's sort of ambiguous, seemingly allowing them to violate you for any random bit of information you didn't collect. I asked him specifically about situations where maybe weather or similar information is not available. He basically explained that yes there is some liberty for application here, but what they are looking for is the sense that the pilot performed reasonable due diligence for that flight. He gave me a specific example. A pilot decided to fly into a remote strip in the winter, but it turns out that the strip was snow covered and he ended up losing control and bending the airplane. There was no weather or notams available for this site. He said he asked questions like: did you gather surrounding weather information to know what the conditions were like in neighboring areas, did you call the restaurant on the field to ask if other airplanes had recently been using the strip, had you spoken with any other pilots who had recently flown into the strip, etc. etc. To him at least, if you are making a clear effort to gather information to ensure that flight can be completed safely, then you've done your part and you've met the requirements of 91.103.

He said it is very apparent when someone just didn't care and much like the police, after dealing with many half-truths they can usually smell BS from a mile away. So do you need a METAR before you can operate from a remote strip. NO. But you probably have an OAT gauge in your airplane, and you can probably find many temp readings from surrounding areas to give you a good idea of what to expect. Did you bother to use those? Did you even care? As far as performance specs for an aircraft, he was very no-nonsense about it, and basically said "if you fly an airplane outside of the published performance specs and it doesn't work out and you have an incident and I have to investigate, do you think I'm going to ask you how you determined it was safe to operate that aircraft in those conditions and what qualifies you to fly a certified aircraft as a test pilot?"...

So, go fly whenever you want, but you're accountable, so be ready to give an account. If you dont like that, well... tell it to the FSDO guy. Or, alternatively, you could just become a Senator and behave like Mr Inhofe and fly wherever, whenever, however you want (your know landing on closed runways and such) and then act like the FAA is infringing your liberties.
 

CoffeeIcePapers

Well-Hung Member
As far as performance specs for an aircraft, he was very no-nonsense about it, and basically said "if you fly an airplane outside of the published performance specs and it doesn't work out and you have an incident and I have to investigate, do you think I'm going to ask you how you determined it was safe to operate that aircraft in those conditions and what qualifies you to fly a certified aircraft as a test pilot?"...
I don't understand this argument. Unless the OAT is a limitation on the aircraft in the limitations section, it is pretty easy to determine the performance numbers based on extrapolation.
 

rframe

pǝʇɹǝʌuı
I don't understand this argument. Unless the OAT is a limitation on the aircraft in the limitations section, it is pretty easy to determine the performance numbers based on extrapolation.
Personally, from a purely common sense perspective, I would tend to agree that extrapolation should make sense, especially when a predictable linear or curve is established, and the extrapolation is limited to a small percentage outside the envelope. But, the inspector I talked to seemed to think this was a black/white issue and it was pretty clear what his position would be if investigating an incident where DA was an issue and the temps were off the performance charts... I suppose the argument is that extrapolation is an untested and theoretical performance value.

If I were regularly operating in a high temperature area, like the southwest deserts, I think I'd try to get a written interpretation from the local FSDO on this, since they are the ones you'd have to deal with.
 

z987k

Well-Known Member
So what happens when I go fly an airplane that doesn't have performance data? Instant violation? Or can we use some common sense there to?

Let me call aerona and see if they'll whip me up some performance numbers... oh wait.
 

jrh

Well-Known Member
Here's what I'm saying; if you wouldn't do it with a fed sitting in the seat next to you, then you shouldn't do it. If you wouldn't say to the fed, "Aw shucks, Bob, it's only 2 degrees C, let's just go! It'll be fine!" Then you shouldn't do it.

Or hey, let me say it like this; if you wouldn't do it on a checkride, then you shouldn't do it. If you wouldn't say to the examiner, "Well, it's kind of hot out, so I ran the performance numbers, but it's a little too hot, but we'd be fine," then you shouldn't do it.
You know, the more I've thought about this, the more I'd be willing to do it with a fed sitting next to me, or on a checkride--under Part 91. I am convinced it is both safe and legal, under Part 91.

We've been talking past each other. I was focused on the safety/legality of *doing* it. You've been focused on a "fly every flight as though it's a checkride" attitude, which, in general, I fully believe in as well. But the only reason I said I wouldn't do it if questioned by a fed is, by the way the question was originally worded, I took it to mean the fed thought it to be wrong--otherwise they wouldn't have brought it up to begin with! I'm never going to thumb my nose at a fed, no matter how ridiculous I think they're being. But I'd be complying with them to appease them, not because I think they're right. Same as how I'd have maintenance look over every little loose screw or scratch if a fed were questioning it, no matter how insignificant.
 

rframe

pǝʇɹǝʌuı
So what happens when I go fly an airplane that doesn't have performance data? Instant violation? Or can we use some common sense there to? Let me call aerona and see if they'll whip me up some performance numbers... oh wait.
Of course not, at the time of certification those specifications and limitations were not required to be published, therefore you're not operating the aircraft outside of any published specifications or limitations, are you?
 

jrh

Well-Known Member
I realize you guys are just messing around, but jrh's question is basically a paperwork issue in his aircraft type.
Actually not quite.

I was wanting to know how it's handled from an operational perspective. We've determined what paperwork is required. I think we're all in agreement that Part 135/121 requires written proof of the numbers.

I was more interested in knowing how this requirement affects other operators, as I see large aircraft using very hot airports. Other posters have largely answered this question in that performance charts extend further (like 52*C rather than 40*C), engineers have tested larger airframes to more extreme ranges, and sometimes they still halt flying in places like the MidEast. Those are precisely the responses I was looking for.

This problem is unique to my operation in that we're using aircraft never intended for airline service, in airline service. Nobody is wanting to do anything illegal or unsafe. We're just caught in a weird intersection between general aviation and commercial airline standards.

Thanks for all the input, everyone.
 

Autothrust Blue

"I'll take your case."
What about old aircraft that don't give you much of anything for performance? Like perhaps they only give you sea level standard day numbers? Am I a dangerous cowboy for operating that aircraft any time it's not 59* F at sea level?

The performance curve isn't changing that steeply, you could easily compute a fairly accurate extrapolation.
My personal sled was certificated under CAR3, and has sufficient performance in most airports--and basically no performance data.

What performance data it DOES have is incorporated by reference into the limitations section--you know, the chapter where each page has the heading "OBSERVANCE OF THESE LIMITATIONS IS REQUIRED BY LAW."

So I guess there's that.

Part 121, or a modern transport category aircraft...no numbers = no go, even if we are empty.


This post is brought to you by Beta. Beta: chicks dig it.
 

CoffeeIcePapers

Well-Hung Member
If I were regularly operating in a high temperature area, like the southwest deserts, I think I'd try to get a written interpretation from the local FSDO on this, since they are the ones you'd have to deal with.
Ultimately, the local FSDO's interpretation means little to nothing. You would need an opinion from FAA legal in DC to CYA.
 

dasleben

That's just, like, your opinion, man
I'm a "time and place" guy, a wearer of many hats so to speak. I fly/drive/drink/talk/ect. differently depending on the time and place. Part 91, middle of no where, I'm going to worry less about what's legal and more about what CAN be done using careful and realistic judgement. Knowing what I know about C172s and 210s, short of the wings falling off, it's going to fly no matter what. Frost, ice, snow, high density alt with along runway; it doesn't matter. I say that with a little bit of sarcasm. Like I said, I prefer to be legal as well, but I guess I take a more realistic approach. I mean, at FLX, we don't have MELs, EVERYTHING is supposed to work. I'm not writing an airplane up for a post light. This, by the book, is illegal, but I don't give a rats poop hole that I can't read the hobbs in flight. Call me dangerous I guess...
You're certainly not dangerous for going without a post light, and I doubt any Fed would care enough to violate you over it.

As far as operating "less than legal" while flying Part 91, that's your privilege as as certificated, PIC rated pilot. Incidentally, the "It's going to fly no matter what" attitude has killed plenty of people who didn't realize they were about to take off for the last time (a prime example). At the very best, you're putting your ticket on the line for no reason.

Keep in mind, all of us saying that you should stick within limitations are perfectly capable pilots, have done what you've done, and have simply learned better.
 

dasleben

That's just, like, your opinion, man
Actually not quite.

I was wanting to know how it's handled from an operational perspective. We've determined what paperwork is required. I think we're all in agreement that Part 135/121 requires written proof of the numbers.

I was more interested in knowing how this requirement affects other operators, as I see large aircraft using very hot airports. Other posters have largely answered this question in that performance charts extend further (like 52*C rather than 40*C), engineers have tested larger airframes to more extreme ranges, and sometimes they still halt flying in places like the MidEast. Those are precisely the responses I was looking for.

This problem is unique to my operation in that we're using aircraft never intended for airline service, in airline service. Nobody is wanting to do anything illegal or unsafe. We're just caught in a weird intersection between general aviation and commercial airline standards.

Thanks for all the input, everyone.
I see what you're saying. At my company, if the winds/temps/weights/etc. aren't within limitations, the computer software we use for performance calculations doesn't even let us print off a TOLD card (Takeoff and Landing Data). No V-speeds, acceleration altitude and stop margin information, etc. The operation is stopped until you have legal numbers.
 

UAL747400

Well-Known Member
You're certainly not dangerous for going without a post light, and I doubt any Fed would care enough to violate you over it.

As far as operating "less than legal" while flying Part 91, that's your privilege as as certificated, PIC rated pilot. Incidentally, the "It's going to fly no matter what" attitude has killed plenty of people who didn't realize they were about to take off for the last time (a prime example). At the very best, you're putting your ticket on the line for no reason.

Keep in mind, all of us saying that you should stick within limitations are perfectly capable pilots, have done what you've done, and have simply learned better.
Yeah, it was late, in a sour mood, and in rant mode. Let me back pedal a bit and say that I agree with being safe AND keeping your certificate safe.

Just to be clear, I wasn't saying I would try to make a 172 fly, but I have seen other people make adjustments(low weight, high rotation speed, shallow climb, ect.) with a long enough runway, get them in the air in all kinds of conditions that I would call shady. I'm too much of a Sally to pull things. :)
 
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