ArchGuy1
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Taking Off and Landing in Heavy Rain

Sat Oct 12, 2019 12:00 am

How do airline pilots deal with taking off and landing in heavy rain that includes torrential downpours.
 
GalaxyFlyer
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Re: Taking Off and Landing in Heavy Rain

Sat Oct 12, 2019 12:09 am

Pretty much like every other take-off or landing. Do the performance data, confirm the runway available is adequate and within the governing regulations. Line up and add thrust, keep the wings level and the nose tracking the centerline. HUD helps, a lot in some cases, but done without one for decades.

GF
 
Armadillo1
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Re: Taking Off and Landing in Heavy Rain

Sat Oct 12, 2019 5:24 am

Wet runways length is an issue for landing, with icing even nore
 
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Starlionblue
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Re: Taking Off and Landing in Heavy Rain

Sat Oct 12, 2019 5:36 am

Take off. As GalaxyFlyer says there's not much difference. Except if there's so much rain the runway is considered contaminated. Then the performance app may tell you to use fixed derate due to VMCG limits. This means TOGA prohibited below a certain speed (F speed on the 'bus).

Landing. Positive touchdown. If the runway is contaminated, use REV MAX. The reversers destabilise the airflow around the rudder, which can lead to loss of directional control during the rollout, particularly on contaminated runways. So if you start drifting off centerline due to the slippery runway, go back to idle reverse.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
Retired57
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Re: Taking Off and Landing in Heavy Rain

Sat Oct 12, 2019 9:49 am

This has to be my all time favorite.

https://www.youtube.com/watch?v=i9IhQxmt08U

nebojsa
 
Max Q
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Re: Taking Off and Landing in Heavy Rain

Sat Oct 12, 2019 11:04 am

Retired57 wrote:
This has to be my all time favorite.

https://www.youtube.com/watch?v=i9IhQxmt08U

nebojsa



It’s a good one


Captain must have had a hot date..
The best contribution to safety is a competent Pilot.


Guns are a malignant cancer that are destroying our society
 
BravoOne
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Re: Taking Off and Landing in Heavy Rain

Sat Oct 12, 2019 7:33 pm

ArchGuy1 wrote:
How do airline pilots deal with taking off and landing in heavy rain that includes torrential downpours.



A pretty good review in this attachment.

http://www.smartcockpit.com/docs/Slippery_Runways.pdf
 
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AirlineCritic
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Re: Taking Off and Landing in Heavy Rain

Sun Oct 13, 2019 10:28 am

What's the effect of heavy rain on engine performance?
 
VSMUT
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Re: Taking Off and Landing in Heavy Rain

Sun Oct 13, 2019 11:45 am

AirlineCritic wrote:
What's the effect of heavy rain on engine performance?


Too much can extinguish an engine.

But it would probably improve the power output by a little, by cooling the air.
 
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AirlineCritic
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Re: Taking Off and Landing in Heavy Rain

Sun Oct 13, 2019 11:55 am

Thanks.
 
BravoOne
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Re: Taking Off and Landing in Heavy Rain

Sun Oct 13, 2019 2:55 pm

VSMUT wrote:
AirlineCritic wrote:
What's the effect of heavy rain on engine performance?


Too much can extinguish an engine.

But it would probably improve the power output by a little, by cooling the air.



I have never heard of an engine flameout on takeoff due to rain?
 
VSMUT
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Re: Taking Off and Landing in Heavy Rain

Sun Oct 13, 2019 3:10 pm

BravoOne wrote:
VSMUT wrote:
AirlineCritic wrote:
What's the effect of heavy rain on engine performance?


Too much can extinguish an engine.

But it would probably improve the power output by a little, by cooling the air.



I have never heard of an engine flameout on takeoff due to rain?


TACA flight 110
Garuda flight 421

I've heard of plenty of cases where 1 engine failed where water ingestion was suspected. If you've ever been through a Malaysian or Indonesian downpour, you won't be in doubt why.
 
BravoOne
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Re: Taking Off and Landing in Heavy Rain

Sun Oct 13, 2019 5:13 pm

VSMUT wrote:
BravoOne wrote:
VSMUT wrote:

Too much can extinguish an engine.

But it would probably improve the power output by a little, by cooling the air.



I have never heard of an engine flameout on takeoff due to rain?


TACA flight 110
Garuda flight 421

I've heard of plenty of cases where 1 engine failed where water ingestion was suspected. If you've ever been through a Malaysian or Indonesian downpour, you won't be in doubt why.



Neither of these flights were during TO, which was the OPs original question. I agree that at times you have a hard time imagining the engines ability to continuously run when in some of these intense water events.
 
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AirKevin
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Re: Taking Off and Landing in Heavy Rain

Sun Oct 13, 2019 5:32 pm

BravoOne wrote:
VSMUT wrote:
BravoOne wrote:
I have never heard of an engine flameout on takeoff due to rain?


TACA flight 110
Garuda flight 421

I've heard of plenty of cases where 1 engine failed where water ingestion was suspected. If you've ever been through a Malaysian or Indonesian downpour, you won't be in doubt why.

Neither of these flights were during TO, which was the OPs original question. I agree that at times you have a hard time imagining the engines ability to continuously run when in some of these intense water events.

Actually, the original question asked about both take-off and landing.
Captain Kevin
 
VSMUT
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Re: Taking Off and Landing in Heavy Rain

Sun Oct 13, 2019 5:37 pm

BravoOne wrote:
VSMUT wrote:
BravoOne wrote:


I have never heard of an engine flameout on takeoff due to rain?


TACA flight 110
Garuda flight 421

I've heard of plenty of cases where 1 engine failed where water ingestion was suspected. If you've ever been through a Malaysian or Indonesian downpour, you won't be in doubt why.



Neither of these flights were during TO, which was the OPs original question. I agree that at times you have a hard time imagining the engines ability to continuously run when in some of these intense water events.


He asked about both takeoff and landing.
 
BravoOne
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Re: Taking Off and Landing in Heavy Rain

Sun Oct 13, 2019 6:10 pm

Sorry as that was not the way I read his post. I was looking at it from a "on the runway" perspective only/
 
BravoOne
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Re: Taking Off and Landing in Heavy Rain

Sun Oct 13, 2019 10:16 pm

VSMUT wrote:
BravoOne wrote:
VSMUT wrote:

Too much can extinguish an engine.

But it would probably improve the power output by a little, by cooling the air.



I have never heard of an engine flameout on takeoff due to rain?


TACA flight 110
Garuda flight 421

I've heard of plenty of cases where 1 engine failed where water ingestion was suspected. If you've ever been through a Malaysian or Indonesian downpour, you won't be in doubt why.


Since you have expanded the original question you might include Southern Airways 242, DC9 that had a double flame out approaching Atlanta as I recall. Probably the biggest reason you don't see this during landing or takeoff is that nowadays pilots are usually not that dumb.
 
GalaxyFlyer
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Re: Taking Off and Landing in Heavy Rain

Sun Oct 13, 2019 10:37 pm

I’m not sure I’d call Southern 242 crew “dumb”. In the ‘70s and ‘80s thunderstorms were NOT nearly as well understood or were looked at as stopping aviation. Review the multitude of wind sear and turbulence related crashes in those days. EA 66 was the first to really investigate microbursts. Heck, unloading bags were done with lightning within 3 miles, even overhead. It’s was the way we did business then. We smartened up, but it was blood lesson.

I vividly remember a take off out of SJU, heavy, heavy rain, lightning, winds of 20-30 knots. Off we went, right after the PAA ahead and another EA and DL behind us. Controller on departure just said, “fly the heading you like and report clear of the weather.”

GF
 
BravoOne
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Re: Taking Off and Landing in Heavy Rain

Mon Oct 14, 2019 2:17 am

GalaxyFlyer wrote:
I’m not sure I’d call Southern 242 crew “dumb”. In the ‘70s and ‘80s thunderstorms were NOT nearly as well understood or were looked at as stopping aviation. Review the multitude of wind sear and turbulence related crashes in those days. EA 66 was the first to really investigate microbursts. Heck, unloading bags were done with lightning within 3 miles, even overhead. It’s was the way we did business then. We smartened up, but it was blood lesson.

I vividly remember a take off out of SJU, heavy, heavy rain, lightning, winds of 20-30 knots. Off we went, right after the PAA ahead and another EA and DL behind us. Controller on departure just said, “fly the heading you like and report clear of the weather.”

GF


Did not mean to infer the Southern guys were dumb as opposed to the current pilots which are well aware of the hazards that await crews that ignore what the industry has learned the hard way in the past. Your scenario works well in a place like SJU but not so well in a place like LAS. Regardless I get your drift.
 
Max Q
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Re: Taking Off and Landing in Heavy Rain

Mon Oct 14, 2019 3:22 am

The Southern flight’s pilots didn’t understand radar attenuation, what they thought was a clear area in the thunderstorm they were heading towards was actually the most severe part of it, so intense that it blocked their radar, reflecting back a return that if you didn’t know better looked like a clear area


Radar attenuation and how to interpret that phenomenon received a lot more attention in training after that accident
The best contribution to safety is a competent Pilot.


Guns are a malignant cancer that are destroying our society
 
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Loran
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Re: Taking Off and Landing in Heavy Rain

Thu Oct 17, 2019 3:20 pm

AirlineCritic wrote:
What's the effect of heavy rain on engine performance?

The fan blades are designed in a way that any objects (water, snow, birds, any other debris) will be moved to the outer part of the fan, so that they do not enter the core stream. Having water in the bypass stream actually increases engine thrust due to the increased mass flow. Too much water in the core stream can lead to a lower temperature in the combustion chamber and reduce engine performance. In other words, modern high-bypass engines should be less prone to performance issues due to rain (or any other objects) due to the relatively small core stream. It depdends a lot on the fan blade design.

As a side note, water injection systems had exactly this purpose, increasing mass flow and hence engine thrust. They also reduced combustion chamber temperatures and hence lead to the distinctive smoke trails.

Regards,
Loran
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remingtonbox
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Re: Taking Off and Landing in Heavy Rain

Thu Oct 17, 2019 4:22 pm

Retired57 wrote:
This has to be my all time favorite.

https://www.youtube.com/watch?v=i9IhQxmt08U

nebojsa


Correct me if I am wrong, but aren't the spoilers extended in that video?
 
LH707330
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Re: Taking Off and Landing in Heavy Rain

Thu Oct 17, 2019 5:58 pm

remingtonbox wrote:
Retired57 wrote:
This has to be my all time favorite.

https://www.youtube.com/watch?v=i9IhQxmt08U

nebojsa


Correct me if I am wrong, but aren't the spoilers extended in that video?

They are, looks like a pretty hefty crosswind....
 
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AirKevin
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Re: Taking Off and Landing in Heavy Rain

Thu Oct 17, 2019 9:35 pm

remingtonbox wrote:
Retired57 wrote:
This has to be my all time favorite.

https://www.youtube.com/watch?v=i9IhQxmt08U

nebojsa

Correct me if I am wrong, but aren't the spoilers extended in that video?

If you turn the ailerons to a certain point, the spoilers on one side of the aircraft start to come up.
Captain Kevin
 
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DocLightning
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Re: Taking Off and Landing in Heavy Rain

Fri Oct 18, 2019 12:00 am

VSMUT wrote:
AirlineCritic wrote:
What's the effect of heavy rain on engine performance?


Too much can extinguish an engine.


OK, but it takes an awful lot. Engines are tested to tolerate water ingestion far above what would be encountered in any real takeoff. If it were raining that heavily, visibility would be too poor to take off.

https://youtu.be/_PR0Ka_J2P4?t=50

https://www.youtube.com/watch?v=faDWFwDy8-U

In fact, water injection into the combustors was used in the past to enhance engine performance. The water cools the inlet air, allowing for more heat to be added, then it boils and expands, increasing total thrust output.
-Doc Lightning-

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Starlionblue
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Re: Taking Off and Landing in Heavy Rain

Fri Oct 18, 2019 12:32 am

DocLightning wrote:
VSMUT wrote:
AirlineCritic wrote:
What's the effect of heavy rain on engine performance?



OK, but it takes an awful lot. Engines are tested to tolerate water ingestion far above what would be encountered in any real takeoff. If it were raining that heavily, visibility would be too poor to take off.



You might have acceptable visibility for the actual take-off and then encounter a rain cell one minute later. Or conversely, when landing you might see the first half of the runway but not the second half. (Yes, this does happen.)

The intensity of tropical downpours is something you have to experience to believe. 100mm (approx 4 inches) of rain/hour us not that uncommon. That's three times as much precipitation in one hour as a northern European city might average in a month.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
muralir
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Re: Taking Off and Landing in Heavy Rain

Fri Nov 01, 2019 6:19 pm

DocLightning wrote:
VSMUT wrote:
AirlineCritic wrote:
What's the effect of heavy rain on engine performance?


Too much can extinguish an engine.


OK, but it takes an awful lot. Engines are tested to tolerate water ingestion far above what would be encountered in any real takeoff. If it were raining that heavily, visibility would be too poor to take off.

https://youtu.be/_PR0Ka_J2P4?t=50

https://www.youtube.com/watch?v=faDWFwDy8-U

In fact, water injection into the combustors was used in the past to enhance engine performance. The water cools the inlet air, allowing for more heat to be added, then it boils and expands, increasing total thrust output.


Those are interesting videos! In the video, they say they test the engines by injecting 4 tons of water per minute into the engine. On a lark, I tried to figure out how much water gets ingested in a heavy rainstorm.

You can model this by figuring out the density of water in the air (Which is a product of how much rain is falling, and how fast raindrops fall). I won't go into the calculations that are done on this page:
https://www.dmcinfo.com/latest-thinking ... op-density

But basically, a 1in/hr rainfall translates to a density of 780mm^3 of water per cubic meter of air. That's 0.78ml H20 / m^3 of air. That sounds really small (less than an mL of water in a cubic meter!). But it adds up. Taking @starlionblue's estimation of 4inch/hour of rainfall during a heavy tropical storm, that translates to a density of 3.12ml/m^3.

Here's where it gets fun. An engine moving through air can be assumed to essentially "clear" the cross-sectional area of the intake portion x the forward motion of the engine. IOW, multiplying the engine intake's cross-sectional area by the plane's speed should give us how much air an engine clears per unit of time. Now, this is a rough estimate because a turbine will actually suck air in, so the actual air intake is likely significantly larger. But unless someone can pipe up with actual numbers for how much air is ingested, I'll use this rough method to calculate it.

The diameter of the GEnx engine is 282cm.
Leading to cross-sectional area of 6.25m^2.

The cruising speed of a 787 is 900kph
This leads to a total volume of air ingested at 5.6million m^3/hr
Which leads to a volume of water ingested at 17million ml/hr = 17,500 liters/hr = 17.5 metric tons of water / hr = 0.3 metric tons of water / minute.

The two big unknowns in my calculations, which I'd love some input on are:
1) When they say 4tons/minute is the testing load, is that metric ton or empiric ton?
2) Is the method of calculating air ingested accurate? Given how powerful these turbines are, I suspect they ingest a lot more air than a simple calculation based on cross-sectional area would imply. I'm sure the numbers have been calculated by GE/RR/PW. Can anyone shed light on that?

At any rate, while the tested rate is comfortably above what would be expected even during heavy rains, depending on assumption #2, even with an impressive number like 4tons/minute, it may not be *that* much more than what an engine can be expected to face during real-life operations!
 
CosmicCruiser
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Re: Taking Off and Landing in Heavy Rain

Fri Nov 01, 2019 8:09 pm

Since you have expanded the original question you might include Southern Airways 242, DC9 that had a double flame out approaching Atlanta as I recall. Probably the biggest reason you don't see this during landing or takeoff is that nowadays pilots are usually not that dumb.

What got those guys was hail. The mistake made which, as someone mentioned, was not so obvious then as now. The line of storms they were trying to penetrate had a very thin area showing on the radar which they chose to go through. Unfortunately it was the worst area and didn't show because of attenuation of the radar. The hail took out the engines as well as cracking both windshields. One tip to test for attenuation now is to lower the antenna and see if it paints ground clutter behind the storm. If it doesn't don't go there.
 
GalaxyFlyer
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Re: Taking Off and Landing in Heavy Rain

Fri Nov 01, 2019 8:26 pm

For one thing, cruising speed is at high altitude where there are few encounters with rainfall rates that high. At mid-levels, say below F240, where those rainfall rates are flown thru, speeds are typically 400 knots or less, below 10,000’ less than 290 knots.

GF
 
frmrCapCadet
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Re: Taking Off and Landing in Heavy Rain

Mon Nov 04, 2019 3:41 pm

The fan blades are designed in a way that any objects (water, snow, birds, any other debris) will be moved to the outer part of the fan, so that they do not enter the core stream


This plus the you-tubes answered the questions for us amateurs.
Buffet: the airline business...has eaten up capital...like..no other (business)
 
Max Q
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Re: Taking Off and Landing in Heavy Rain

Fri Nov 08, 2019 10:22 am

Interesting Concorde trivia


Concorde pilots were very reluctant to use windshield wipers on take off

The reason was if the wipers didn’t stow properly then the visor would not be able to lock closed in the up position


Without the visor closing and properly streamlining the nose section supersonic flight was not permitted and they would have to return to the departure airport


Not really an issue anyway as it’s acceleration was so rapid on take off that any water on the windshield was quickly blown off
The best contribution to safety is a competent Pilot.


Guns are a malignant cancer that are destroying our society

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