Bombardier CRJ hot weather capability
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Bombardier CRJ hot weather capability
The National Post (Canada) is reporting on the recent hot weather in Arizona:
"Boeing and Airbus planes flew fine throughout the heat wave, but pilots cannot fly the Bombardier CRJ in extreme weather"
Is this intrinsic to the CRJ design or did Bombardier simply choose not to get the plane certified at higher temperatures?
"Boeing and Airbus planes flew fine throughout the heat wave, but pilots cannot fly the Bombardier CRJ in extreme weather"
Is this intrinsic to the CRJ design or did Bombardier simply choose not to get the plane certified at higher temperatures?
Did you read the article? It says exactly what the problem was.
A Canadian-made plane caused all those hot-weather flight delays in Phoenix: airline | National Post
A Canadian-made plane caused all those hot-weather flight delays in Phoenix: airline | National Post
In brief - the CRJ manual(s) don't give data (e.g. runway length required, etc.) for a takeoff in temperatures above 48°C (at 1100 feet elevation). Therefore it is not legal to do so, and the plane is grounded.
Why? The main reason is - Bombardier did not choose to calculate/provide information for higher temperatures.
Now, the deeper "why?" - why Bombardier chose to do (or not do) that, is not explained. The NP could not get a comment from Bombardier.
Thus Niallo's question.
The NP article gives some possible (speculative) explanations, but without an affirmative confirmation from Bombardier, they are just speculations. Maybe it is a limitation of some one individual component in the design - or maybe it was simply that Bombardier thought 48°C (50°C at sea level) was "enough," and didn't want to spend the extra time and money to extend the operating range calculations to (in their opinion) extremely unlikely temperatures. Or maybe it was something else.
Why? The main reason is - Bombardier did not choose to calculate/provide information for higher temperatures.
Now, the deeper "why?" - why Bombardier chose to do (or not do) that, is not explained. The NP could not get a comment from Bombardier.
Thus Niallo's question.
The NP article gives some possible (speculative) explanations, but without an affirmative confirmation from Bombardier, they are just speculations. Maybe it is a limitation of some one individual component in the design - or maybe it was simply that Bombardier thought 48°C (50°C at sea level) was "enough," and didn't want to spend the extra time and money to extend the operating range calculations to (in their opinion) extremely unlikely temperatures. Or maybe it was something else.
Does the CRJ, and for that matter, other FAR 25 aircraft (Boeing, Airbus), have a permissible operating temperature range listed in the "Limitations" section of the Flight Manual? I ask because it was a feature of helicopters certified to airline transport standards that I flew.
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In brief - the CRJ manual(s) don't give data (e.g. runway length required, etc.) for a takeoff in temperatures above 48°C (at 1100 feet elevation). Therefore it is not legal to do so, and the plane is grounded.
The 48°C is a cert based on a multitude of factors, but really it is MTOW. ie at MTOW, with ALL of the other factors in a cert, there is a temp limit (based on sea level pressure.)
When the temp gets higher, you need to limit MTOW to the point where you cannot meet the DEP climb rate/obstacle clearance for the SID. It is a simple if/then, but the reality is that MTOW gets limited before max temp.
Cert assumes the worst case scenario, ie MTOW, max bleeds, min engine perf, and a host of other variables. (even icing on at max temp ?!?!) The airline performance people are the ones who decide if the ac can DEP given the cert and the parameters.
Some airlines that operate at airports with higher temps, go above and beyond the cert parameters, and have custom DEP procedures that provide the required obstacle clearance.
Regarding the article,
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.
Last edited by underfire; 26th Jun 2017 at 06:41.
