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bio15
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Is This A Test For The Engines?...

Fri Sep 02, 2005 11:51 pm

Several days ago I saw an MD80 being truck-towed to the far end of a taxiway just beside the runway. Then the truck made a couple of turns until it parked the aircraft as shown in red:


Copyright Jeppesen Sanderson Inc.

Then it turned on the engines and was kept there for more than an hour. During that time it lasted about 15 minutes at full power (my guess) and then back to idle for a short time. Theres a nice spot just behind the threshold, and the three times I've been there I have seen different aircraft do this same procedure.

Are these procedures engine test runs? Why isn't this done at the hangars, or somewhere near the maintainance area? I don't recall seeing mechanics aroud the plane during the run.

I also wanted to ask, what is that symbol on the taxiway that is two circles connected by a line just prior to entering the runway? Does it have something to do with this engine runs? Thanks in advance

Alfredo
 
SlamClick
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RE: Is This A Test For The Engines?...

Sat Sep 03, 2005 12:32 am

The

Quoting Bio15 (Thread starter):
I also wanted to ask, what is that symbol on the taxiway that is two circles connected by a line just prior to entering the runway?

It is a designated stop bar, or holding point. If you are not cleared into position on the runway you must stop so that no part of the airplane extends beyond that line. If you have just landed but have not received any clearance to taxi you must exit the runway past that point, so that no part of the airplane extends beyond that line.

* * *


Some maintenance procedures require engine runs at high power settings, but probably not "full" power. I'll let the guys who know what they are talking about speak to that. They are done at a remote location because the jet blast would do damage nearer the ramp or hangar. Also the noise level would be excessive for those in the hangar or ramp areas who would have to endure it.

Jet blast? Well, if those engines will make a 160,000 lb. airplane fly five hundred miles per hour, will they make your 500 lb. toolbox fly 160,000 MPH?
Happiness is not seeing another trite Ste. Maarten photo all week long.
 
bio15
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RE: Is This A Test For The Engines?...

Sat Sep 03, 2005 1:04 am

Thanks Slamclick, I see why the runs can't be performed near the hangar areas. To be honest, it turned into a really boring experience after the first few minutes since the engines roared so incredibly loud. I remember a low frequency hum all the time and my ears were aching a bit. The spot is right where the grey line crosses the approach lights, pretty St Marteenesque  Smile

The airport is BOG. The other four runway ends do not have this line, I was wondering why would the hold line only be placed at this threshold? Do you have an idea of what things are done during this runs?

Alfredo
 
Matt72033
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RE: Is This A Test For The Engines?...

Sat Sep 03, 2005 1:25 am

normally monitor certain indications, EGT at certain N1 %'s Vibration, Pressures that kinda stuff!

i saw one done today inside the hangar, they only do Idle runs though!
 
airbusA346
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RE: Is This A Test For The Engines?...

Sat Sep 03, 2005 1:56 am

Is there any photos on A.net of Engine Runs.

Tom.
Tom Walker '086' First Officer of a A318/A319 for Air Lambert - Hours Flown: 17 hour 05 minutes (last updated 24/12/05).
 
SlamClick
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RE: Is This A Test For The Engines?...

Sat Sep 03, 2005 4:00 am

Quoting Bio15 (Reply 2):
The airport is BOG. The other four runway ends do not have this line, I was wondering why would the hold line only be placed at this threshold?

Don't know why having never been to Bogota. (Have been to Cucuta, however) perhaps that is the primary airline arrival runway?
Happiness is not seeing another trite Ste. Maarten photo all week long.
 
air2gxs
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RE: Is This A Test For The Engines?...

Sat Sep 03, 2005 4:09 am

Quoting SlamClick (Reply 5):
Quoting Bio15 (Reply 2):
The airport is BOG. The other four runway ends do not have this line, I was wondering why would the hold line only be placed at this threshold?

Don't know why having never been to Bogota. (Have been to Cucuta, however) perhaps that is the primary airline arrival runway?

The line may be there because this could be the primary run-up pad for high power run-up operations. The line lets the mechs know where not to put the aircraft.
 
amtrosie
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RE: Is This A Test For The Engines?...

Sat Sep 03, 2005 10:22 am

Pictures of an engine run???


Yeh, its called an flying (or taking-off/landing) aircraft.
 
EMBQA
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RE: Is This A Test For The Engines?...

Sat Sep 03, 2005 10:52 am

Why isn't this done at the hangars, or somewhere near the maintenance area?

Because the hangar would act as a big echo chamber, and it would be VERY LOUD in there..!! Most airports require you to go out the a 'run pad' to perform high power runs for noise abatement.
"It's not the size of the dog in the fight, but the size of the fight in the dog"
 
2H4
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RE: Is This A Test For The Engines?...

Sat Sep 03, 2005 11:16 am




Quoting AirbusA346 (Reply 4):
Is there any photos on A.net of Engine Runs.



Ask, and ye shall receive.....



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Photo © M Radzi Desa
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Photo © Bruce Leibowitz




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Photo © Israel Gándara
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Photo © Colin T. Ebert




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Photo © Bruce Leibowitz
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Photo © Lindsay Hockey





2H4


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airbusA346
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RE: Is This A Test For The Engines?...

Sat Sep 03, 2005 7:17 pm

2H4, is there any more like the Malyaisian 777 pic, with all the structure round it.

And how did you find them in the seach function on A.net.

Also is there any good photos on A.net of the engine run area, which LH Technik use, if think its at MUC or HAM, i can not remember.

Thanks

Tom.
Tom Walker '086' First Officer of a A318/A319 for Air Lambert - Hours Flown: 17 hour 05 minutes (last updated 24/12/05).
 
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HAWK21M
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RE: Is This A Test For The Engines?...

Sat Sep 03, 2005 8:27 pm

High Power runs are normally carried out at such remote locations Either with Exhaust pointing towards a Blast fence or a wide space behind to avoid damage from the Velocity & Temperature of the Exhaust Airflow.

Normally We'll taxy the Aircraft to the Location & carry out the High power run & chk the parameters required.If trimming is required.Engine RPM is reduced to idle & settings are carried out.But during High power runs No personnel around inside the Safety zone limits.

The location as stated is because of Noise Pollution & Likelyhood of Exhaust Airflow induced damage Occuring.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
bio15
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RE: Is This A Test For The Engines?...

Sun Sep 04, 2005 4:57 am

Thanks everyone, it's pretty clear.

Quoting HAWK21M (Reply 11):
If trimming is required.Engine RPM is reduced to idle & settings are carried out.But during High power runs No personnel around inside the Safety zone limits.

Now that you mention it, I recall seeing a small open door on the engine case, but nobody was around. This is during the high power run. I assume that the mechanic went somewhere around that door when at idle but I didn't catch an eye on this.

Here at BOG there is no structure built to stop the exhaust stream so that's why the jets are aimed away from anything damagable, from what I understand. Yet the sound is terribly annoying, and this is at a considerable distance! I can't imagine the sound standing just 30 meters away or so.


Alfredo
 
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HAWK21M
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RE: Is This A Test For The Engines?...

Sun Sep 04, 2005 6:19 pm

Quoting Bio15 (Reply 12):
Yet the sound is terribly annoying, and this is at a considerable distance! I can't imagine the sound standing just 30 meters away or so.

Thats where Ear Defenders & Ear Plugs are Mx best Friend  Smile


regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
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Starlionblue
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RE: Is This A Test For The Engines?...

Mon Sep 05, 2005 3:01 am

Quoting HAWK21M (Reply 13):
Quoting Bio15 (Reply 12):
Yet the sound is terribly annoying, and this is at a considerable distance! I can't imagine the sound standing just 30 meters away or so.

Thats where Ear Defenders & Ear Plugs are Mx best Friend

The important thing with very loud noises is to wear BOTH ear plugs and protectors. That's what we did when firing 84mm recoilless rifles. BLAM! Even so, my ears would ring for several minutes.

[Edited 2005-09-04 20:01:51]
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
SkydrolBoy
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RE: Is This A Test For The Engines?...

Mon Sep 05, 2005 4:46 am

At my work the only place we can do engine runs is on our company ramp outside our hangars. It sure makes the inside of the hangar loud when you've got a 727 at takeoff power outside. I love doing trim runs on the 727 and standing underneath all three engines at rated-power and feeling the power of the engines vibrating through you.
 
bio15
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RE: Is This A Test For The Engines?...

Mon Sep 05, 2005 7:39 am

Quoting SkydrolBoy (Reply 15):
I love doing trim runs on the 727 and standing underneath all three engines at rated-power and feeling the power of the engines vibrating through you.

How dangerous is it to be so close at high power? I would have thought that underneath the engines there's a high risk of getting ingested, are you tied to the floor?

I imagine the feel, it must be really energizing  yell 


Alfredo
 
2H4
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RE: Is This A Test For The Engines?...

Mon Sep 05, 2005 11:14 am




Quoting AirbusA346 (Reply 10):
2H4, is there any more like the Malyaisian 777 pic, with all the structure round it. And how did you find them in the seach function on A.net.



Sorry I've taken so long to reply....I forgot I posted in this thread. I found the previous shots by searching for keywords "engine" and "runup", I believe. Anyway, here are some shots that include jet blast deflectors:






http://www.empireacoustical.com/images/Full_Size/Blast_deflector_Grissom_AFB.gif

http://www.empireacoustical.com/Applications/Airports_Mass_Transit/Utah%20-%20Salt%20Lake%20City%20airport%20-%20blast%20deflector%201.jpg

http://www.empireacoustical.com/Applications/Airports_Mass_Transit/Utah%20-%20SLC%20airport%20-%20blast%20deflector%202.jpg


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Photo © Agustin Anaya
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Photo © TJ OKeefe




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Photo © Daniel Asplund
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Photo © Stewart Andrew




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Photo © Gerhard Plomitzer
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Photo © MSF




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Photo © Daniel Asplund
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Photo © Sunbird Photos by Don Boyd




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Photo © JLS Photo







Hope those help you out!




2H4


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futureuapilot
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RE: Is This A Test For The Engines?...

Mon Sep 05, 2005 11:29 am

Our Jetblast ramps are just hills made when they were leveling the runways here at ATW. The blast is so strong, the grass is still blowing on the side facing away from the aircraft.

-Sam
The Pilot is the highest form of life on Earth!
 
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HAWK21M
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RE: Is This A Test For The Engines?...

Mon Sep 05, 2005 1:20 pm

Quoting Bio15 (Reply 16):
are you tied to the floor

There are safety belt attachments,for Idle/PP runs.For T/O runs no personnel is before the Safety limits.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
SkydrolBoy
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RE: Is This A Test For The Engines?...

Mon Sep 05, 2005 5:40 pm

Bio15,

Yes it is pretty dangerous to be that close, if your not paying attention you could be injested. At my work we dont tie ourselves down, we would either have to tie ourselves to the engine (which you couldn't pay me to do) or have to use a manlift with safetybelt attachments, but there is too much of a chance of FOD injestion with the manlift (cause no matter how clean it looks theres always a hidden screw or nut laying on the dam things).
 
gocaps16
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RE: Is This A Test For The Engines?...

Fri Sep 09, 2005 10:15 am

We place a net cage around our intakes while we're turning our jets, either low power or high power turns, even the slightest FOD cannot be sucked in. It is also a safety device for our personnel doing leakage checks during a run.

Kevin
 
planefreakaa
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RE: Is This A Test For The Engines?...

Tue Sep 13, 2005 11:34 pm

the chances are that if it was a super 80 being at that location, they were probably doing a engine trim, meaning they were setting the fuel control. as far as being at that location it is probably has to do with airport regulations. at ord, we have to go to a hush house to perform our run-ups, yes we can do minimal runups at the hangar area, but the blast fences at the hanger were not built to withstand the blast from a super 80 at take off epr.
 
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Francoflier
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RE: Is This A Test For The Engines?...

Tue Sep 20, 2005 2:31 am

They do run them near the hangars from time to time, at low power though...

Quoting AirbusA346 (Reply 4):
Is there any photos on A.net of Engine Runs.

Here's one that I like:


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Photo © Mike Primamore

I'll do my own airline. With Blackjack. And hookers. In fact, forget the airline.
 
Dougloid
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RE: Is This A Test For The Engines?...

Tue Sep 20, 2005 6:25 am

Quoting Francoflier (Reply 23):
Here's one that I like:

That one comes under the heading of Hot and Juicy-Dave Thomas'd be proud of the new use of his slogan.
If you believe in coincidence, you haven't looked close enough-Joe Leaphorn

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