Sparking on the 737 engine front stage
Thread Starter
Joined: Jul 2001
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From: planet earth
Sparking on the 737 engine front stage
Hi all,
I work at an airfield above the Artic circle and we use a lot of sand to keep the ramp etc free of ice.
I have noticed when 737s have their engines running, sparks / flashes around the outer part of the disc, next to the engine casing. Looks good but it got me wondering.
Is this sparking caused by sand particles being ingested into the engine when they strike the fan blades ? And as I was always under the impression that only fresh air was meant to pass through the engine, where does this fit in with FOD ingestion / damage ?
Thanks for any answers !
C130JB
I work at an airfield above the Artic circle and we use a lot of sand to keep the ramp etc free of ice.
I have noticed when 737s have their engines running, sparks / flashes around the outer part of the disc, next to the engine casing. Looks good but it got me wondering.
Is this sparking caused by sand particles being ingested into the engine when they strike the fan blades ? And as I was always under the impression that only fresh air was meant to pass through the engine, where does this fit in with FOD ingestion / damage ?
Thanks for any answers !
C130JB
Joined: Dec 2010
Posts: 1,165
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From: Middle America
Sparking
c130jbloke
Your observation is correct. The fan blades are made from Titanium, Ti6-4 alloy to be exact. It is the same alloy used to make titanium golf club heads. They, too, spark when being hit from a tee that has sand accumulation or when hitting out of a sand trap, impressive at dawn or dusk!
Observing it at the fan casing is good as it means the majority of the sand particles are being flung outward and will pass through the fan by-pass instead of being ingested into the core. Over time, some erosion will result at the tips of the fan blades or in the acoustical liners along the walls of the fan casing.
Turbine D
Your observation is correct. The fan blades are made from Titanium, Ti6-4 alloy to be exact. It is the same alloy used to make titanium golf club heads. They, too, spark when being hit from a tee that has sand accumulation or when hitting out of a sand trap, impressive at dawn or dusk!
Observing it at the fan casing is good as it means the majority of the sand particles are being flung outward and will pass through the fan by-pass instead of being ingested into the core. Over time, some erosion will result at the tips of the fan blades or in the acoustical liners along the walls of the fan casing.
Turbine D
Joined: Dec 2010
Posts: 1,165
Likes: 0
From: Middle America
Gulfstreamaviator
Couldn't find any photos of sparking of the fan, but here is what I meant using the golf club example:
YouTube - Golf club sparks
Turbine D
Couldn't find any photos of sparking of the fan, but here is what I meant using the golf club example:
YouTube - Golf club sparks
Turbine D
Avoid imitations



Joined: Nov 2000
Aviation Qualifications: ATPL
Posts: 15,115
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From: Wandering the FIR and cyberspace often at highly unsociable times
A similar thing occurs on the main rotor blades on some helicopters when some types of dust/sand hit them. For example, the Sikorsky S-76, which by no coincidence, has titanium leading edge protection strips.
Joined: Feb 2008
Posts: 93
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From: USA
A rather good link for this one, nice pics.
The Kopp-Etchells Effect
The Kopp-Etchells Effect




