Part 135/121 operations during extreme temps

jrh

Well-Known Member
Just wondering, how many operators out there have had issues with flying during times with outside air temperatures beyond published performance charts for the aircraft?

It's been a hot point (pun intended!) at my company recently because our takeoff/landing performance charts end at 40*C (104*F), yet temperatures have occasionally exceeded this in some of our destinations.

One particularly interesting scenario is the legality/safety of taking off with OATs within charted limits, only to have the OAT climb beyond the performance charts while enroute.

How do other charter and airline operations handle these scenarios?
 

ZapBrannigan

Old School
We were down for the count in Vegas last summer. Didn't have climb limit numbers due to high temperatures. Had to wait until the next morning and depart while we were still on the charts.

We're part 91 though.
 

Nark

Sheepdog
On the other side of the spectrum, the company I worked for in Alaska set arbitrary numbers as a temperature cutoff. I think it was -48 for the pistons, -45 for the turbines. Something like thats.

As for 121 op's, the aircraft has temperature limitations, generally 40C (at least for my sexy Brazilian) . Also min temps, for various operations, battery, start etc...
It's an aircraft imposed limitation, not a company one.
 

SteveCostello

My member is well-known.
OK, so here's a question. Big Cheese in the back wants to get home in time for Little Susie's play, and OAT is 2º of the charts. You are clearly well within limits for the end of your performance chart. Easy to armchair pilot and say, "Hey! Sorry, Mr. BC, but we're stuck here in Hades," but I hear more than the occasional story of the pressures that the guys paying the bills can exert, directly or otherwise.

You know the operation is safe, he knows the operation is safe, but there is no documentation to support that assertion. What's the call?
 

ZapBrannigan

Old School
(shrug) I don't get paid to test pilot. I get paid to operate safely within the limitations of the aircraft.

It would be unethical for me to claim safety without data to back it up.

Now, that said, we would try to anticipate the problem and arrange to depart earlier in the day - or delay until that night. We won't be asked to violate regulations or operate unsafely. The headline risk (of an accident) to the company is much too great.
 

jrh

Well-Known Member
You know the operation is safe, he knows the operation is safe, but there is no documentation to support that assertion. What's the call?
That's exactly why I focused on the 135/121 side of the industry.

Under 91, I'd be going. 135/121 is much more by the book. The feds actually come down on 135/121 operators for flying 1 knot/1 degree/0.25 miles beyond the limits of something, whereas they don't really care about Part 91 stuff until metal gets bent, or a pilot goes WAY beyond what they ought to be doing.
 

Polar742

All the responsibility none of the authority
Just wondering, how many operators out there have had issues with flying during times with outside air temperatures beyond published performance charts for the aircraft?

It's been a hot point (pun intended!) at my company recently because our takeoff/landing performance charts end at 40*C (104*F), yet temperatures have occasionally exceeded this in some of our destinations.

One particularly interesting scenario is the legality/safety of taking off with OATs within charted limits, only to have the OAT climb beyond the performance charts while enroute.

How do other charter and airline operations handle these scenarios?
If you don't have a number, you can't go.

That's from 2 121 operations. A "commuter" or "regional" and a worldwide heavy operator. It comes up a lot in the MidEast. Gotta wait for the temp to drop.

Jimflyfast would have a legit answer.
 

jtrain609

Uniting the black vote.
That's exactly why I focused on the 135/121 side of the industry.

Under 91, I'd be going. 135/121 is much more by the book. The feds actually come down on 135/121 operators for flying 1 knot/1 degree/0.25 miles beyond the limits of something, whereas they don't really care about Part 91 stuff until metal gets bent, or a pilot goes WAY beyond what they ought to be doing.
Ok, say the FAA inspector is standing next to you. How are you going to explain the legality of taking off without having the performance information? If they don't get you on 91.103, they'll get you on 91.13.
 

jrh

Well-Known Member
If you don't have a number, you can't go.

That's from 2 121 operations. A "commuter" or "regional" and a worldwide heavy operator. It comes up a lot in the MidEast. Gotta wait for the temp to drop.
Pretty much what I figured.

I don't have any experience with larger aircraft. Do they typically have performance charts for a wider range of conditions than smaller aircraft? Say, for example, performance data all the way up to 50*C? I see 737s, MD-80s, 757s, etc. blasting off all afternoon in the heat.

Also, how is it handled if temperatures exceed limits after you're enroute? Divert, the same as for visibility below minimums for an approach, or that sort of thing?
 

rframe

pǝʇɹǝʌuı
Ok, say the FAA inspector is standing next to you. How are you going to explain the legality of taking off without having the performance information? If they don't get you on 91.103, they'll get you on 91.13.
I had an inspector explicitly tell me that if you do not have performance numbers (not extrapolating), you are flying the airplane outside of it's performance limitations, and you are not legal... doesn't matter if you're John Doe in a Cherokee weekend flying by yourself.

Of course a 91 operator is probably much less likely to get asked unless they happen to also break something at the same time.
 

jrh

Well-Known Member
Ok, say the FAA inspector is standing next to you. How are you going to explain the legality of taking off without having the performance information? If they don't get you on 91.103, they'll get you on 91.13.
A few thoughts--

You and I both know the way things work with an inspector next to you and the way they work by yourself aren't 100% in line 100% of the time. I wasn't explaining the textbook answer, I was explaining what would happen in the real world most of the time.

91.103 requires a pilot to be "familiar" with performance data. I think a reasonable argument could be made that although the pilot can't calculate takeoff/landing distances to the foot, if their 172 manual says they need 3000 feet of runway on a 40*C day, it's safe to use a 9000 foot runway with no obstacles at 42*C. They are *familiar* with what the aircraft will do.

I'm doubtful any Part 91 pilot has gotten in trouble for this type of violation, either legally or safety-wise. Accidents and certificate actions happen after strings of more significant problems. If you're aware of case law that contradicts this, let me know.

There are all sorts of scenarios under Part 91 that this situation becomes laughable. What about airports with no weather reporting? What about off-airport operations, such as are common in bush flying? "Not having the numbers" means you would NEVER go in those cases. There comes a point where it really needs to be left up to the pilot's judgement, which is the beauty of most Part 91 flying.
 

dasleben

That's just, like, your opinion, man
Yes, you need to wait. Pilots at your company have been known to be rather lax on computing performance data (ask how I know), but that doesn't mean the FAA doesn't care.
 

crazyjaydawg

Well-Known Member
Pretty much what I figured.

I don't have any experience with larger aircraft. Do they typically have performance charts for a wider range of conditions than smaller aircraft? Say, for example, performance data all the way up to 50*C? I see 737s, MD-80s, 757s, etc. blasting off all afternoon in the heat.
From operational and engineering experience I can attest that larger 121 carriers have a higher range on their charts, but they occasionally run into problems. Currently performance for a 121 op is stored in a computer database and best fit numbers for the day considering runways, winds, temps, obstacles, etc are pulled from that database are either printed out or sent via ACARS to the aircraft and subsequently flight crew for usage. That has many limitations.

Moving forward though, airlines will be calculating performance numbers in real time using exact calculations from the aircrafts' manufacturers and interpolating them with a complex computer program that creates brand new, custom-made numbers for that aircraft on a specific leg, for a specific runway at the exact time, place and conditions. It will allow operators to operate more often in challenging conditions and maximize payload. No more rounding down, or making conservative guesses. It will be real time specific stuff. While the change will be very small from an crew member's point of view and unnoticed by a passenger, the change in possible revenue generated (or less being left behind) will be huge!

edit:
Also, how is it handled if temperatures exceed limits after you're enroute? Divert, the same as for visibility below minimums for an approach, or that sort of thing?
Yes! Ask many of the rj pilots flying into small airports in CO this summer. The high and hot operations force a lot of enroute diversions because they couldn't get landing numbers.
 

jrh

Well-Known Member
Yes, you need to wait. Pilots at your company have been known to be rather lax on computing performance data (ask how I know), but that doesn't mean the FAA doesn't care.
I'm on the morning shift, before it heats up, so the debate doesn't really affect me. Everything I do is within limits no matter what.

But yes, I hear ya. The FAA was doing route checks here for the past two days. I have a couple stories, but only PM- and meet-n-greet-worthy.
 

Screaming_Emu

Great and Unmatched Wisdom
You and I both know the way things work with an inspector next to you and the way they work by yourself aren't 100% in line 100% of the time. I wasn't explaining the textbook answer, I was explaining what would happen in the real world most of the time.
I very much disagree with this statement. While I'm not perfect, I TRY not to do anything in the airplane that I wouldn't do with a fed on the jumpseat. 1) It makes it easy to explain everything you were doing should a problem arise 2) When a fed is on the jumpseat you don't get that uneasy "driving by a police station" feeling.

Most of the time I like my job. I'm not going to do anything on purpose that is going to risk it. Even more so, every time I see a paycheck I think "If I ever hurt or kill myself for this little money, I'm going to be very pissed off."

Not worth the risk, wait till night time. Honestly, in the back of a twin cessna when its this hot probably isn't a fund place for passengers to be anyway. I get they have places to be, but even in my APUed twin pack canuckjet we'll hold off boarding and delay a flight until the plane cools down.
 

jtrain609

Uniting the black vote.
A few thoughts--

You and I both know the way things work with an inspector next to you and the way they work by yourself aren't 100% in line 100% of the time. I wasn't explaining the textbook answer, I was explaining what would happen in the real world most of the time.

91.103 requires a pilot to be "familiar" with performance data. I think a reasonable argument could be made that although the pilot can't calculate takeoff/landing distances to the foot, if their 172 manual says they need 3000 feet of runway on a 40*C day, it's safe to use a 9000 foot runway with no obstacles at 42*C. They are *familiar* with what the aircraft will do.

I'm doubtful any Part 91 pilot has gotten in trouble for this type of violation, either legally or safety-wise. Accidents and certificate actions happen after strings of more significant problems. If you're aware of case law that contradicts this, let me know.

There are all sorts of scenarios under Part 91 that this situation becomes laughable. What about airports with no weather reporting? What about off-airport operations, such as are common in bush flying? "Not having the numbers" means you would NEVER go in those cases. There comes a point where it really needs to be left up to the pilot's judgement, which is the beauty of most Part 91 flying.
As a pilot, I disagree with your analysis, and would not like to be in your shoes if something went wrong while you were bending the rules. I doubt you could roll off the end of the runway and get away with saying you were familiar with the data. If you don't have the data, you're not legal.
 

jrh

Well-Known Member
I very much disagree with this statement. While I'm not perfect, I TRY not to do anything in the airplane that I wouldn't do with a fed on the jumpseat. 1) It makes it easy to explain everything you were doing should a problem arise 2) When a fed is on the jumpseat you don't get that uneasy "driving by a police station" feeling.
Oh, I totally agree! I flew with a fed next to me for a couple legs this week and had no trouble at all because I do things by the book, at a by the book operation.

Just to be clear, my defense of taking off 2*C beyond performance charts is limited to *Part 91*. I was answering SteveCostello's post, implying Part 91 corporate ops. I agree with the consensus here for Part 135/121 ops.

Limits are limits. Part 91 or 121/135. The "real world" excuse is BS.
I agree. Thing is, I'm not sure the performance charts under Part 91 are limits. As I detailed in my response to Jtrain, all sorts of things are allowed under Part 91 that aren't an option under Part 135/121. You tell me--how should I stay legal when taking off Part 91 out of Uncle Bob's farm strip in a Caravan? There are no numbers to run! I'd have no way of knowing winds, temperature, or runway length. How is this permissible, while departing a 10,000 foot runway at an airport with weather reported at 2*C beyond the chart is not allowed?

My mention of the "real world" was in response to Jtrain bringing up the idea of a fed questioning the action. Feds have a way of picking apart ANYTHING. It's best to agree with them and move on, no matter how insignificant or silly their issue is. I've seen a fed question a pilot over a "wiggly" gas cap. The pilot had no doubt the gas cap was airworthy, but you know his response? "Yes sir, I better get maintenance to look at it."

A fed might question a pilot over departing Part 91 one degree outside of performance charts, and in that case, it would be stupid not to say whatever is necessary to keep them happy. However, that doesn't make it illegal or unsafe to do otherwise.


I'm leaving on a six hour road trip now. Have fun discussing amongst yourselves tonight!
 

jrh

Well-Known Member
As a pilot, I disagree with your analysis, and would not like to be in your shoes if something went wrong while you were bending the rules. I doubt you could roll off the end of the runway and get away with saying you were familiar with the data. If you don't have the data, you're not legal.
Ok, we can agree to disagree.

One simple question though...are you saying every Part 91 flight that flies to/from an airport where "having the data" is impossible, such as a mountain airstrip with no weather reporting available, is operating illegally?
 
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