Aircraft grounded due to climate change; some background info

Raise the alarm bells, folks; aircraft are being grounded because of climate change. We’re hooped. It’s all over. There goes the reliability of the aviation industry. The wings have been clipped.

Or, let’s take a closer look at the latest “sky is falling” panic attack from the climate change alarmists.

Have aircraft been grounded due to extreme heat? Yes, and I’m sure that caused some significant inconvenience for some people at the time. But is this indicative of some kind of long-term detrimental impact on the aviation industry? According to the article, in the future,

During the hottest part of the day, 10 to 30 percent of planes will have to offload cargo or people, according to a new study by graduate student Ethan Coffell and climate scientist Radley Horton at Columbia University. “This study shined a light on a potential vulnerability,” Horton says. “A lot of airplanes at full capacity are ill-equipped to take off on some of the world’s runways when temperatures get really high.”

Should we be concerned?


As a thought experiment, let’s take them at their word. The basis for their concern is this,

As the Earth’s climate undergoes a 1 to 3 degree Celsius warming over the next half-century, extreme heat waves will hit more frequently.

They ought to have clarified, “IF the Earth’s climate…” because the track record of climate predictions hasn’t exactly been stellar, to date. I digress.

Ok, so the fundamental cause of the concern is a 1 to 3 degree change in temperature. I agree, that would mean there are more days that exceed the maximum. But let’s read the fine print. They clarify that, “at the hottest part of the day…” Ok, so the 10 – 30% problem is only for a certain time of day. Let’s assume half of all travel takes place on those days. That means the real problem will only strike half of the 10 – 30% of flights, or no more than about 5 – 15 % of flights.

And only on days that are really hot days. This isn’t exactly going to be a problem in Chicago in January, for instance. If we assume one full month out of every year has such “extreme heat” every single day (I think that’s generous, your call…) then the 5 – 15% becomes 1/12 of those values, or 0.42 – 1.25% of all flights.

Or, roughly speaking, one out of every one hundred flights, annually, will be impacted by global warming. And not that the flights are necessarily grounded, just that they may have to leave some passengers and their luggage behind. Let’s assume one out of every ten passengers and their luggage get left behind in those circumstances. This is obviously outlandishly high, but I prefer round numbers. That means 1/10th of passengers on the 1% of flights that are impacted will have to be delayed. And let’s assume they are selected at random.

That means for every 1,000 flights you go on you’ll have one flight where you get selected to stay behind. If you took exactly one flight every single day of the year it would be about once every three years that you’d be asked to stay behind.

But only if you fly out of airports that experience extreme heat at some point in the year; if you stick to more northerly destinations then you’ll never be asked to stay behind. Unless you fly United airlines, I suppose, in which case all bets are off.

And – this isn’t stated, but implied – this catastrophic impact will only transpire if there are absolutely no technological developments in aviation over the course of the next fifty years. They took data from currently existing aircraft to conduct their calculations on future impacts of global warming on air travel.

That alone should have us scratching our head.

Let’s dig in a little deeper.

It needs to be pointed out that not all aircraft respond to extreme heat the same, as this article reports. Not surprisingly, Canadian aircraft were the one’s rated to the lowest “high temperature” cutoff. Canada is renown for its cold temperatures, not its hot temperatures, so it should surprise exactly nobody that we haven’t been at the forefront of pushing the boundaries on extreme heat operation.

And just how big was the gap between Canadian made airplanes and airplanes developed elsewhere?

And with the mercury just peaking at 48 in Phoenix on both Tuesday and Wednesday, all its [Bombardier] CRJs were grounded.

Meanwhile, Boeing and Airbus planes flying into Sky Harbor International Airport remained fine throughout the heat wave.

The various 737s, 747s and 777s made by Boeing can stay in operation until temperatures hit 52 C, an American Airlines spokesman told the National Post. French-made Airbus products, meanwhile, can operate until 53 C.

So the Canadian-made aircraft can operate up to 48C and the other guys can operate up to 52C or 53C. That’s a difference of 4 or 5 degrees Celsius.

But wait! Over the course of the next fifty years it’s only supposed to warm up 1 to 3 degrees Celsius. Which means, even if there is absolutely zero technological development in aviation, Boeing and Airbus aircraft will still be in pretty good shape fifty years from now.

What’s really going on here? Can 4 degrees Celsius really make all that much of a difference? I mean, is the Bombardier airplane going to burst into flames and kill everybody on board at 48.1 degrees Celsius if the pilot accidentally flicks the “on” switch?

The Bombardier CRJ is still physically able to fly, of course, but pilots do not have performance charts on how the aircraft will behave in extreme temperatures.

“Sometimes, above certain temperatures, data simply doesn’t exist. In that case, taking off isn’t an option,” reads a recent blog post by commercial pilot Patrick Smith, author of Cockpit Confidential.

In theory, then, the plane could fly without any problems at all; the manufacturer just hasn’t done flight testing up to those temperatures (or, by some other method, produced flight data for those temperatures).

As a guy with a pilot’s license I can speak to this a little bit. Pilot’s get extremely anxious about operating past, or even near, the documented limits of the aircraft. I remember carefully calculating weight and balance on the little Cessna 152 during flight training, then comparing my calculations to the published data in the Pilot Operating Handbook (POH). If my calculation ended up outside the published data then I wasn’t going to fly the airplane. Period. End of statement.

You have to understand something about airplanes; if something goes wrong, you cannot pull over and call AMA. Problems at 30,000 feet are vastly more significant than problems on Deerfoot Trail. And if you have dozens, or hundreds, of souls in the aircraft behind you, I imagine airline pilots are ever more cautious than guys like me who only fly recreationally.

So if the flight data goes up to 48C and not one fraction of a degree higher, then I completely understand that the pilot would ground the flight if the temperature outside were 48.1C.

As an engineer, of course, I also recognize that the 48C limit is almost certainly arbitrary. As the article illuminates,

The reasons for the CRJ’s low maximum operating temperature could be due to something as simple as a single electronic component that isn’t certified for hot weather.

If even one seemingly insignificant component on the aircraft is only rated for 48C then the entire aircraft is rated for 48C. That’s how engineering works. But that seemingly insignificant component might be fine to operate up to 60C, it’s just that the manufacturer never certified it for operation up to those temperatures. When the risks are as high as they are for aviation, manufacturers, pilots and airlines exhibit unusual levels of caution. It’s that caution that ensures that most of time when you step onto an airplane you will safely step off of that same airplane at your destination.

Are they anal? Heck yeah; and you’re alive.

If you want to get a sense for the significance of what’s at stake, here’s an extremely interesting documentary. The first 5-7 minutes covers enough info to help you get the point.

All that background should make one fact fairly obvious; expanding the envelope probably isn’t a big deal! If I were Bombardier I’d go back to the design team and ask how they arrived at 48C as the limit.

  1. Perhaps one or more of the components is only rated to 48C. Ok, fine, can we ask the manufacturers of those components to test those components to, say, 55C instead? That will be the new standard going forward. Problem solved.
  2. Perhaps the flight test program only went up to 48C, never beyond. Ok, fine, can we get the test pilots to push that limit up a little bit and provide flight data to the new limit? That’s a bit more of a costly fix – there’s a lot more flying involved – but once the boundary has successfully and safely been expanded that opens up the entire fleet to the new limit. Again, that’s probably more of a “going forward” solution, but still, problem solved.

The original “sky is falling” article assumed no advance in aviation technology, but some of the “advance” might be extremely simple and suddenly the envelope is expanded with minimal effort. Is it reasonable to think that might happen some time in the next fifty years? Honestly, I’d be surprised if Bombardier hadn’t addressed this in two years.

Well, actually, this is Bombardier. They would probably need a whole lot more taxpayer money first…

Just how fast does aviation technology advance? One of the aircraft used in the analysis was the Boeing 737. I found some flight data for the 737 online at this link. I’m going to compare take-off data for the 737-100 (page 104ish) with the 737-900ER (page 158ish). Just to compare apples to apples, I’ll look at a takeoff weight of 100,000 lb.

For the 737-100 a 100,000 lb takeoff weight is pretty close to the upper limit. The chart on page 104 only goes up to 110,000 lb. However, for the 737-900ER 100,000 lb is at the bottom of the range. The max take-off weight is nearly 190,000lb.

110,000 lb up to 190,000 lb max take-off weight. Have they made advancements over the years? Oh, heck yeah!

Also to compare apples to apples, let’s assume an extremely high altitude takeoff at 10,000 ft Above Sea Level (ASL). For context, Calgary is only about 3,500 feet ASL.

The takeoff distance for the 737-100 at 100,000 lb weight, and 10,000 feet ASL is…

… trick question. It can’t do it. It can barely take off at 6,000 ft ASL, and it requires about 11,500 feet of runway to do so.

On the other hand, the 737-900ER, loaded to 100,000 lb and taking off at 6,000 ft ASL gets off the ground in just under 4,000 ft. That’s about one third the distance.

And, unlike the 737-100, the 737-900ER is capable of taking off at 10,000 ft ASL; it can do so (at 100,000 lb capacity) in somewhere between 4,500 feet and 5,000 feet of runway. Still less than half the 737-100 at only 6,000 feet.

Interestingly, Boeing provides data for high temperature performance. For the 737-900ER it provides data all the way up to “standard day + 35C” which, at sea level, is about 50C. At 10,000 feet ASL that’s about 30C. Even under extreme heat conditions the 737-900ER is capable of taking off at 10,000 ft
ASL and 100,000 lb capacity in just over 5,500 feet of runway.

So the early generation Boeing 737 weighing in at 100,000 lb was nearly at max load, and couldn’t take off from an airport any higher than 6,000 ft ASL on a standard day. A later generation 737 weighing in at 100,000 lb isn’t anywhere close to its maximum weight and it can take off from 10,000 ft ASL on an extreme heat day.

Here’s a little more info about the history of this widely used commercial aircraft from Wikipedia.

So, in summary, am I concerned about the impact of global warming on the aviation community 50 years from now? Let’s review.

The first flight of the first Boeing 737 was in 1967. That’s 50 years ago, this year. The first flight of the 737-900ER was in 2006; about 40 years after the maiden flight of the first 737. The improvements in performance (including extreme heat performance) during that time have been staggering. And the performance improvements in the past 50 years clearly outpaced even the worst-case scenarios for global warming in the next 50 years.

There is a reasonable likelihood that technological advancements in the future will not match the pace of technological advancements in the past (a subject for another blog) but we certainly have not reached some kind of aviation glass ceiling. There’s plenty of room for improvement left, and even if the improvements in the future are only a fraction as impressive as the improvements in the past, we’re still massively outrunning the glacial pace of global warming (assuming the forecasts are remotely accurate).

Am I concerned the sky is falling on the aviation community?

Not at all.