Too hot to fly?

[AmericanFlyer]

Phoenix heat wave: Too hot to fly? - 3TV | CBS 5 (http://www.azfamily.com/story/35664500/phoenix-heat-wave-too-hot-to-fly?utm_source=fark&utm_medium=website&utm_content=link&ICID=ref_fark)

[ironbutt57]

the article is actually surprisingly accurate

[Cheltman]

I was in Phoenix in June 1990 and remember it well.
On a Northwest 727 for MSP I think. Used every bit of the runway and climb was very gentle. I also recall feeling the heat through my shoes off the tarmac

[BRE]

Little anecdote on the side: The 727 ended up being a tri jet because United needed it for its hot & high Denver hub.

[MarkerInbound]

That day in 1990 everyone shut down when the temp went off the performance charts. SW paid Boeing that day for higher temperature performance data. All the other airlines figured it was a one time event. The next day the temp went off the charts again and all the other airlines had to shut down again. SW just kept flying.

[tdracer]

It's not just "too hot". A year or two after EIS of the 747-8, we had a number of 747-8 aircraft grounded in Europe when a cold front moved in and dropped the pressure altitude below -1000 ft. - and Boeing hadn't published performance data lower than -1000 ft.
We quickly produced performance charts to -2000 ft. pressure altitude...

[Danny42C]

Step Turn (#5),

This snippet from my Page 153 #3056 on "Pilot's Brevet" (MilitaryAviation Forum) may amuse: (We are at RAF Willingdon Island, Cochin, S.India, summer 1945).

"I was disentangling myself from my harness and about to climb out, when the Duty Flight Corporal came dashing up indignantly in full Traffic Warden mode: "You can't leave that there 'ere !". I clearly remember shrugging my Mae West off one shoulder to show my rank cuff. It made little difference: "You can't leave that there 'ere, SIR !"

Why not ? For answer he pointed wordlessly at the Liberator, and I saw that the lower half of the main wheels had sunk through the tarmac. It was down to the axles already, and how they were ever going to get it out, Heaven only knows (like Fareastdriver's C5 at Honiara a few Posts ago).

It seemed that the local contractor who built the airfield had skimped on this patch, there was no foundation - nothing but sand under a thin skin of tarmac ! My Corporal was worried that the same might happen to me. I reassured him: it was very unlikely as I was only staying an hour or so, whereas the Lib had taken a night and a day to get into that state.

At lunch in the Mess, it was a major topic of conversation, and many were the solutions on offer. One of the better ones was: as the Far East war was over and it was a Lend-Lease aircraft, we should invite the Americans to come and take it away - if they could. Otherwise we'd put a low chain fence round it, leave it and declare it a War Memorial ! "

[ChrisVJ]

According to the news here La Vegas and other parts of Nevada and Arizona are about to suffer a spectacular heatwave, 120F, this week and airlines are cancelling flights.

I understand air density and density altitude but I am surprised that these temperatures are enough to cancel flights days in advance.

Can anyone quantify this in layman's terms? eg,, say, percent performance loss above a certain temperature or something?

[AerocatS2A]

The problem isn't performance per se, it's having the data to quantify the performance. If your take-off performance data tops out at 50ºC / 122ºF (as ours does) then you can't go flying when the temps are hotter than that. If it tops out at 45ºC, then that's your limit.

[Mark in CA]

American Airlines had to cancel a bunch of flights at Phoenix sirport because of the extreme heat there. According to the report, the Bombardier CRJ aircraft they were using has a maximum operating temperature of 118 degrees. Tuesday's forecast for Phoenix included a high of 120 degrees.

Why wasn't AA operations able to anticipate this?

https://www.usatoday.com/story/travel/nation-now/2017/06/19/its-so-hot-phoenix-they-cant-fly-planes/410766001/

[noflynomore]

Who says they didn't? Seems vanishingly unlikely somehow.
But anticipating it would have changed what, exactly? The weather? The certification?
Is this trolling?

[Piltdown Man]

ChrisVJ - Aerocat is spot on. Our data also stops at 50 degrees. As for numbers, at our main base we can normally lift a full load from any runway from any intersection. On one particular runway we have 3,800 metres of tarmac. At 50 degrees Celsius we can only 43,700 kgs. At 46 degrees we can lift 45,000. This means that each degree at this temperature is 325 kgs or 3.5 passengers with bags or just over 10 minutes of fuel.

That was a well written article though. Clearly that reporter doesn't have a future, he'll have to reduce his accuracy and standards if he expects to get on!

[747-8driver]

Is this trolling?
Just because you don't have an answer to his/her question?
AA might have been able to chose a different aircraft to operate out of Phoenix that day.
One that has a higher max. operating temperature.

[Chris2303]

I guess that didn't want a repeat of DXB?

[student88]

DXB? Your post is a bit vague - please may you expand?

[ironbutt57]

Cant remember the ISA limitation on the A320 family aircraft, the largest fleet AA operates out of PHX, but I do remember when I lived there we were grounded more than once by certified OAT limitations (ISA+40) on the aircraft I was flying

[RAT 5]

Has Mr. WAT been at work again. Does it even still apply to modern beasts? There was the case, 20 years ago, at MXP, after much extensive resurfacing work to one runway where the truth was unearthed, literally. No doubt the cheapest tender had been accepted, or it was the cousin of the mayor, or it was the uncle of the airport manager, or......but he first take off of a heavy, on a very hot day, gouged chunks out off the new surface. Dodgy black stuff from the back of a lorry had been spread, it was suspected.

[MarkerInbound]

Why wasn't AA operations able to anticipate this?

Sounds like they did. The USA Today story says AA told folks Saturday there were going to be problems.

AA might have been able to chose a different aircraft to operate out of Phoenix that day.
One that has a higher max. operating temperature.

And how's that going to work? The CRJs aren't flown by AA but by their regional affiliates. But putting that aside are you just going to pull a 150 -180 seat aircraft off its route and replace it with an 80 seat aircraft?

[ilvaporista]

Has Mr. WAT been at work again. Does it even still apply to modern beasts? There was the case, 20 years ago, at MXP, after much extensive resurfacing work to one runway where the truth was unearthed, literally. No doubt the cheapest tender had been accepted, or it was the cousin of the mayor, or it was the uncle of the airport manager, or......but he first take off of a heavy, on a very hot day, gouged chunks out off the new surface. Dodgy black stuff from the back of a lorry had been spread, it was suspected.
Might have been off the same back of a lorry lot that flew away after a Royal Air Maroc 737-200 opened the taps at TRN last year (or maybe the one before that)in hot weather. Happened right in front of my eyes. Whole strips of ashphalt blown away like paper.

[aterpster]

During my airline career 1964-90 I recall both KLAS and KPHX being shut down for temperature limits a few times, but only for a few hours in the afternoon.

A bit of historical perspective.

[OFBSLF]

Just because you don't have an answer to his/her question?
AA might have been able to chose a different aircraft to operate out of Phoenix that day.

How could they do that? It is not like their affiliates have fleets of different types of aircraft sitting around on the tarmac that they can pick and choose from.

[Mad (Flt) Scientist]

Has Mr. WAT been at work again. Does it even still apply to modern beasts?

Although the news stories (such as BBC) talked, in effect, about performance limits, the issue is almost certainly the certified operational temperature envelope, which really speaks to systems qualification, not a/c or system capability as such.

[Chris2303]

DXB? Your post is a bit vague - please may you expand?

The EK 777 that crashed during the missed approach on a flight from TRV. Rumour has it the temperature was over the 50 degree maximum for the airplane

[pax britanica]

Back in the eighties when I was working on that side of the world we were told an urgently needed spare part for a satellite ground station couldnt be delivered as promised because the part was made in Az and the aircraft it was on could not be pushed back from a freight stand because the tarmac was too soft in the heatwave they were having.

never really did find out if it was true or an innovative excuse from the shipper, it certainly was reportedly extremely hot there though.

This thread has made the mainstream news of course with the idea that planes cannot fly when its hot when the truth of course is more along the lines of Network Rails expanding rails when the trains have to run slower.

[RexBanner]

The EK 777 that crashed during the missed approach on a flight from TRV. Rumour has it the temperature was over the 50 degree maximum for the airplane

So nothing to do with the fact they tried to initiate a go around with the engines still at idle then?

[Zaphod Beblebrox]

This thread started with a news story about an internal memo on PHX hot weather operations.

The pertinent section of that memo is:

Oh yeah, it’s hot hot hot
PHX is expected to see high temperatures range from 116 to 119 degrees through Wednesday, which will impact our operations. Our regional partners Mesa and SkyWest won’t be able to operate their aircraft once the temperature reaches 118 degrees, and our mainline aircraft may be weight restricted. If you plan to non-rev via PHX during this time period, be prepared with alternate travel plans, or connect via a different hub if possible. To those of you dealing with the heat, stay safe, stay cool, stay hydrated and thanks for continuing to take care of our customers and each other.


The particulars, confirmed by my F/O a former CRJ driver, is that Canadair did not certify the CRJ family at temperatures above 117 degrees F. When it gets above that the aircraft are outside the certification limits, and parked until the temperature drops inside certification limits. The Airbus and Boeing's can still operate, but obviously they don't lift as much weight at those temperatures.

As to the Airline anticipating this condition, they have and Doug Parker does everything on a cost analysis basis. He needs and wants more RJ's on thinner routes out of PHX. There is this heat limitation and Doug will look at the analysis of temperature outside the limits vs. the cost of operating larger mainline aircraft on that route. He will accept that for a few days out of the year, in the afternoons only, he may not be able to operate and may have to delay flights until the evening.

It is simply a cost benefit analysis and the analysis goes to more RJ's despite the limitations.

[pattern_is_full]

During my airline career 1964-90 I recall both KLAS and KPHX being shut down for temperature limits a few times, but only for a few hours in the afternoon.

Still the same - the cancelled flights are mostly between 3 and 6 pm.

@Marc in CA et al: The cancelled flights are "American Eagle" regional flights, operated by Mesa Airlines, which uses only CRJ regional jets and thus has no other type to substitute.

American can't be pulling larger jets out of their own schedule to cover for the contractor.

Mesa Airlines US Airways Express / American Eagle Airline Information (http://www.mesa-air.com/content.aspx?pageID=16458)

I doubt soft asphalt plays any role - KPHX is all concrete, so far as the airline ramps, taxiways, and runways are concerned.

[lomapaseo]

AA might have been able to chose a different aircraft to operate out of Phoenix that day.
One that has a higher max. operating temperature.

Not withstanding aircraft systems or runway conditions, the engines anticipate hot day, gross weight, altitude takeoff limitations. If you push them too far towards the corner point the tired engines of any vintage may exceed turbine temp limitations on takeoff.

I would expect that an airline the size of AA would have to be able to anticipate this weeks in advance in order to adjust schedules so only fresh engines out of the shop flew into and out of PHX that day.

[MarkerInbound]

I would expect that an airline the size of AA would have to be able to anticipate this weeks in advance in order to adjust schedules so only fresh engines out of the shop flew into and out of PHX that day.

Let's break it down.

Airlines are required to do performance calculations before each takeoff. One of the items used in the calculations is air temperature. If the current temperature is beyond the range of temperatures in the performance database you can't get the required performance data and therefore can not takeoff.

[Brakes...beer]

As far as I recall, 54 deg C is the environmental limit for Boeing and Airbus take-offs. Not many places get hotter than that.

[lomapaseo]

Let's break it down.

Airlines are required to do performance calculations before each takeoff. One of the items used in the calculations is air temperature. If the current temperature is beyond the range of temperatures in the performance database you can't get the required performance data and therefore can not takeoff.

True, but not all engines are equal after they have been in service so you have to assume a limitation that covers these variations.

I have no problem with them sitting on the ground so I was just explaining the difficulty of scheduling a more tolerant machine.

[mn_test347]

The problem isn't performance per se, it's having the data to quantify the performance. If your take-off performance data tops out at 50ºC / 122ºF (as ours does) then you can't go flying when the temps are hotter than that. If it tops out at 45ºC, then that's your limit.

Is it not likely that the take-off performance data tops out where it does because that's the limit that the aircraft can operate with a reasonable payload? Although not impossible, wouldn't a manufacture be silly to build an aircraft for ISA+45ºC and only certify it to ISA+35º.

[fantom]

The trigger-happy mod who deleted my post might do well to reflect that there are contributions to be made here.

[tdracer]

True, but not all engines are equal after they have been in service so you have to assume a limitation that covers these variations.
It's not just the engine itself (e.g. EGT limits). The airframer needs to certify that all the components will operate within their respective temperature limits at the aircraft certified temperature limits. Many of the on-engine accessories are right at their max temp limit when operating at very high ambient temperatures.

[AerocatS2A]

Is it not likely that the take-off performance data tops out where it does because that's the limit that the aircraft can operate with a reasonable payload? Although not impossible, wouldn't a manufacture be silly to build an aircraft for ISA+45ºC and only certify it to ISA+35º.

I think it is more likely that they don't bother certifying it for temperatures that are only experienced very rarely anywhere in the world.

I fly a BAe146, certified for ISA+35, and there is nothing particularly limiting about the 50º line in the performance charts for a descent sized runway (>2000 m).