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How close would you have to stand

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How close would you have to stand

Old 2nd Jul 2003, 18:57
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Question How close would you have to stand

Hi everyone, I wondered if anyone could answer this question for me.
How close to the jet engine of an aircraft such as the 737 and 757 would you have to stand to get 'sucked in' , say at take off thrust and when the engines are idling?!
Many thanks,
Dan
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Old 2nd Jul 2003, 19:19
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I was once told by a 737 pilot that the answer was 13 feet in front to six feet behind the engine nacelles - with the power at ground idle.

Dunno if it's true though - never tried it. Though I've often seen a bright yellow line painted down the side of the nacelles and wondered if it was a "do no stand forward" line.
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Old 2nd Jul 2003, 23:11
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It does happen. Back in the 80's, an engineer was tragically killed at Hatfield after being sucked into the engine of a BAe 146 doing ground runs. I believe that he had been warned/admonished on a number of previous occasions for standing too close.

Last edited by spekesoftly; 3rd Jul 2003 at 20:01.
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Old 2nd Jul 2003, 23:14
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sucked in!

Not long ago we had a mechanic sucked into a JT-3 on one of our DC-8s. He was lying on the tarmac checking an oil filter, approx. 5 feet back of the intake. The ground was icy, so he didn't have much traction. As the engine was spooled up, he was sucked up into the intake. The crew running the engine knew something was wrong (compressor stalls) and shut it down quickly. Fortunately he got hung up on the guide vanes, and was un-injured. (He couldn't hear very well for a while, but now he jokes about it. I'll bet it'll never happen to HIM again.)
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Old 3rd Jul 2003, 18:31
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Thanks for the replies everyone, I never expected the distance on the 737 to be 13 feet when the engines are at idle!! I wonder how far away you could stand from a 'heavy' aircraft such as the 777 and 747?!!
Many Thanks
Dan
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Old 4th Jul 2003, 06:34
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Yeh your 737 pilot was right - the maintenance manual states 13ft in front at idle, and I think 1500ft behind!!, but this is taken from the red warning stripe on the cowls, Boeing's 737 manual also gives the part no. and description of a harness that can be connected at certain points under the cowl so that you can be in there doing leak checks on an idle run.

If we have to go under the cowls of a running engine on the 73, you can safely walk (crouch) right under the centreline of the airplane and walk aft until you are in line with the back edge of the fan cowls and then straight out towards the engine and enter the fan cowl from the back. This is only done if really necessary, most of the time I will shut the engines down if the guy's need to go under the cowls for any reason as it is much safer. The jet engine will always win a fight between engineer and engine unless you are very, very lucky!! I've had my fair share of leak checking running engines and it still makes me very nervous, there is soo much going on at once.

Never intend to find out whether 13ft is correct or not I'll stick to 130ft if its O.K with you!
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Old 7th Jul 2003, 06:08
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So are your posts saying that even behind the intake on some engines you can be sucked forward and around into the intake fan? Seems to me that pulling air from behind the intake would reduce the overall amount of thrust put out by the engine.
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Old 8th Jul 2003, 00:03
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A probby that goes back to the dawn of jets - Frank Whittle found it necessary to fit a coarse wire-mesh guard over the intake on one of his original engines in order to catch foreign objects, oily rags and the like and potential "ingestees".
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Old 9th Jul 2003, 01:18
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obviously can't confirm this one due no personal experience but was once told that it's not even a case of a slight breeze that rips past your ankles first, or a gentle pre-ingestion wafting of the trousers, but more a case of you could be standing safe in one position, move six inches and...................see ya!

Don't know and don't want to know - any thoughts about the possibility of this?
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Old 9th Jul 2003, 01:53
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Re the Hatfield incident, I can't recall if the individual had previous warnings as Speke has suggested. From my memory of that accident (I wasn't there, but had recently left the company) is that a contributory factor was that the 'lab coat' type of coat being worn, was not fastened up and this contributed to him being drawn into the engine. I had always been taught from day one don't go near them with loose/unfastened clothing, presumeably to minimize the chance of this sort of accident occuring. Again my memory banks seem to recall that he was standing to the side of the engine, and was drawn round the cowling into it.

Just for interest, it was a high power run and the area where it happened had no fencing and was relatively near a road and walkway. Many thousands of runs must have been done over the years there, so with the benefit of hindsight its surprising that other incidents had not occurred before that.

The above is from memory of people there and also local paper reports at the time, they may not be totally accurate, but to the best of my memory are.
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Old 9th Jul 2003, 19:05
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A good rule of thumb I was taught when I was learning the ropes on the ramp...

If the engines are idling, don't go any closer to the front than past the nosewheel.

Larger engines have larger distances between front of fan and nosewheel..
Haven't seen any jet powered tail-draggers though.. May have to re-think with one of those!!
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Old 15th Jul 2003, 23:03
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I remember the Hatfeld incident too (at the time working for Air Weapons across the field). The story we heard was that the gentlemen in question had been warned on several occasions about distances and one day, he just pushed his luck that inch or two too far. I was told by someone who met his widow that BAe handled the aftermath with great dignity.
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Old 15th Jul 2003, 23:43
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Once saw an engineer doing a leak check walk right past the intake on a 737-200 at idle,he was a big lad and no doubt this helped to keep his feet on the ground.
Sad thing about it was he thought he was being cool- those of us watching just thought he was a ******!

Last edited by Jetdriver; 16th Jul 2003 at 05:05.
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Old 16th Jul 2003, 08:51
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Same thing happend a few times with maintenance people checking the gear doors while they where open, they suddenly closed with them in between... not a very nice sight...
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Old 20th Jul 2003, 16:57
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Thanks very much for the replies everone, much appreciated. How can somebody only loose a limb by being sucked into a fan spinning at an extortionate RPM - any protective clothing worn for the engineers?
Many Thanks,
Dan
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Old 22nd Jul 2003, 03:29
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...during my time as a/c Mechanic we worked on CF6-50 /-80 mounted on a test rig. There were nice yellow lines painted on the ground which gave you a one meter wide 'walkway' to the engine, in order to do leak tests while the engine ran idle power.
Talk about not stepping on the wrong side of the line...
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Old 23rd Jul 2003, 22:03
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hi!

just thought i'd add my bit. when studying for my aero HND the instructor told of a story about a guy who got pulled into an engine whilst it was on a ground run. the engine was running full power and when he went in his chest hit the cone on the fan stopping him from being digested. unfortunatley this didn't stop his arms and legs getting pulled through the fan but worst thing was these engines pull a massive 200 tonnes of air a sec through them at full power! now i cant imagine 200 tonnes of air but it sounds a hell of a lot! anyway so when the engine was shut down and the guy fell out they found out that not only his hands and feet had gone but his eyes had been pulled out their sockets ant his lungs and other internal parts were partly in his mouth and throat. Not nice at all.

So, never go near the intake of an engine may it be at idle or full power! some aircraft taxi using idle thrust so it shows how powerful they are!

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Old 23rd Jul 2003, 22:14
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I saw a ladder get sucked through an 747 engine on the test stand. It was there one second and an instant later it was gone. Not gonna say which one, but I have seen a recent engine test where the thrust reverser literally ripped off the back of the engine. See if anybody can guess which one.
 
Old 24th Jul 2003, 15:44
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Any reason why engines cannot be fitted with filters to prevent ingestion of any foreign objects while engines are running?Something to do with airflow or what ??
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Old 24th Jul 2003, 20:20
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I remembered this thread last week as I sat in the 777 at LGW waiting to go. With the engines at idle, you could see the vortices in surface water (it had been raining) being pulled up to the intake. I shudder to think what the suck would be at full whack!
Something about golf balls and hosepipes comes to mind.......
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