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.

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.

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

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.

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

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.

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

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

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.

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.

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.

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.

difference between certification and performance
 

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.

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

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.

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).