Airbus Helicopters Max Temp Limit of ISA + 35 Explained

This video explains the Airbus Helicopter temperature limit of ISA + 35
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[@unkhan2167]

Very easy teaching and claring the doubts.

[@EUROSAFETYTRAINING]

thanks

[@Steeyuv]

I wish I wish I WISH every manufacturer made videos as good as these! I suppose I'll just have to get a rating on the 350B3 and fly that.

[@EUROSAFETYTRAINING]

Thank you for your support!

[@giliardferreira4607]

excellent

[@helij9365]

Let's say you are at KPHX - Phoenix Sky Harbor Airport in the summer. The metar reports 115 F which is below the 50 degree operations limit .The VEMD however is at 120 F due to the temp probe reading the heat coming off the ramp -which is above the 50 degree limit. Are you then above the 50 degree temperature limit for operations or are you ok to fly? Thanks!

[@EUROSAFETYTRAINING]

This is a good question that is often asked. The temp limit is not 50, it is ISA+35. Fifty was the cap they put on it because in Israel ISA + 35 can get you above 50 which is a limit on many components on helicopter. So as a pilot in the US you disregard 50 and use ISA + 35. In Phoenix the temp limit would be 47.7. The temperature limit is based on the effects of high temperature on components and longevity of components on the helicopter. If the helicopter is operating in those temperatures the limit applies. Reported temperature is the temperature somewhere different than the helicopter, hence the helicopter is not effected by that temperature. If there will be high temperatures it is best to park the helicopter on a surface that will not create higher temperatures.

[@helij9365]

@@EUROSAFETYTRAINING Thank's for the reply! Much appreciated!

[@airplanemechanic5561]

Thanks!

[@EUROSAFETYTRAINING]

You bet!

[@EUROCOPTERB3E]

Thank you a lot, I didn't understand that concept!

[@EUROSAFETYTRAINING]

Glad it helped!

[@dennismcharney]

Question. Since this is a temperature limitation, why does altitude have a bearing on it? If I burn my arm with a 500 degree rod at sea level I will suffer the same burn that I get with the same temperature rod touching the same part of my anatomy in Leadville, Colorado. Put another way, why can the helicopter tolerate higher temperatures at sea level than it can at higher altitudes?

[@EUROSAFETYTRAINING]

As an aircraft ascends to higher altitudes, the air becomes less dense. As temperatures goes up air becomes less dense. A combination of of those two factors reduce aerodynamic lift. Turboshaft engines rely on the intake of air to generate power. With decreasing air density, the engine may experience reduced power output. The engine's power output is directly related to the mass of air entering the engine, so less air at high altitudes means less power. The main rotor's efficiency is also affected by the lower air density at higher altitudes. The rotor may need to work harder to generate the required lift, resulting in increased fuel consumption and potential limitations on payload capacity. In extreme cases, especially during rapid changes in altitude or under certain flight conditions, the reduced air density can lead to compressor stalls. A compressor stall occurs when the airflow through the engine's compressor becomes disrupted, leading to a momentary loss of engine thrust and potential mechanical stress. Or simply... thats where they tested it too and every operated properly... Beyond that value you become a test pilot.

[@Vitharium]

In simple terms, does this mean that it is not recommened to fly to the bottom of the dead sea with this helicopter because the tempreture limit exceeds the cap imposed?

[@EUROSAFETYTRAINING]

Not at all, completely safe to fly there but you have to limit the temperature to 50

[@nullpointer1]

Ok, but what is this limitation protecting against?

[@EUROSAFETYTRAINING]

When looking at limitations that a manufacture has placed on an airframe there are many possible reasons why that limitation exists. When looking at the temperature limitation the first part of the answer is that the aviation authorities require the manufacture to place a maximum temperature that the helicopter can operate within. When testing the helicopter they have found that aerodynamically the helicopter can perform normal maneuvers, the components operate properly and the helicopter components make their time limit when a specified temperature is adhered to. If you are asking what will happen if you go above this limitation, the simple answer is that all assurances that have been established for the aircraft no longer are valid. So for instance if you operate the helicopter at 54 degrees, as proven by pilots who have done this, the helicopter will continue to operate. Much like exceeding your VEMD FLI limitation of 10 to lets say 11 will not cause the engine to fail immediately. But by doing so all assurances that the engine will make its TBO or power are void. Like the saying goes, if you need power to save your life ... wow that engine can produce alot of power. But now your TBO may be 10 min. In other words if you exceed the temperature limitation you are now a test pilot and there are no guarantees what will happen with the helicopter.

[@mrflyingdriver]

Let’s say at 12000 ft the OAT is 28 C. Are we still within temperature limit?

[@EUROSAFETYTRAINING]

Hello, the max temp at 12000 HP is 26 so 28 would be above the limit

[@tonycadavidhernandez8505]

So.. if I’m in a location where the ISA+35 is for example 46C Is 46C the limitation correct? or it would be 50C??

[@EUROSAFETYTRAINING]

Yes you are correct, the limit is 46 at 2000ft. The limited to 50 was added to make sure the ISA+35 math did not go above 50. its a cap to the limit. So this limited to 50 will only effect you if you are landing at the bottom of the dead sea. Other words its ISA+35

[@tonycadavidhernandez8505]

@@EUROSAFETYTRAINING absolutely clear… thank you so much!!