59

Modern high-bypass turbofan engines work by pulling in immense volumes of air and accelerating it. A screen as proposed would make that task far more difficult, which would ruin the efficiency of the engine. It's also pretty well unnecessary. Jets worldwide take plenty of birdstrikes every day. Unless the pilots see it (hitting the windscreen will do ...


29

As a generic answer, not unusual. Besides personal objects like bucking bars, clecos, rags and such left in tanks, the biggest contamination source, from my experience working on a production line many many years ago, is "swarf". Swarf is aluminum drill shavings and mountains of it are created during assembly. You will also get wire cutoffs and other ...


18

Screens were actually used on the first prototypes of the Me-262, but soon abandoned when they were found to be more of a burden than a help. If you look carefully at the picture of the Me-262 V3 below, you can see the spherical screens on both engine intakes. Today, screens are used only in ground tests. See the picture below for the Rolls-Royce version: ...


17

A few Russian/Soviet fighters had retractable FOD screens on their engine intakes (MiG-29 and Su-27 IIRC). The assumption was that they would operate from damaged runways or roads and the engines would need protection against Foreign Object Damage (FOD). Right air intake of a MiG-29 with main doors closed and louvres on the wing root opened.


16

There are three problems with this idea: (1) To make a screen strong enough to withstand the body of a 15-to-20 pound bird hitting it at 500 miles per hour, would require thick wire which would significantly block air flow. (2) Such a screen would be very liable to collect ice, so it would have to be heated to high temperature. This would be expensive and ...


9

How does the Harrier avoid engine damage from dirt ingestion during rough-field operations? The short answer is that they don't. They avoid using these FOD-laden strips if possible, but doesn't have any kind of active method for reducing FOD damage from debris ingestion. This is supported by an RFP that NAVAIR put out asking for proposals to reduce FOD for ...


9

When flying any surface that is exposed to the air will generate drag. That screening, although full of holes, will create significant drag when exposed to the air that is entering in the airplane. Also, it will distort the air entering the engine reducing the efficiency of the engine and increasing fuel comsuption. Globally, the extra drag and the higher ...


8

Turbofans on commercial airliners are tested against hail, up to 'golf ball size', and ice is harder than a golf ball. Think back to Taca 110, that lost both engines while descending through a hailstorm reported to be up to golf ball size. What killed the engines wasn't the impact of the hail, but the amount of water ingested into the engines. It seems ...


7

Is there a risk? Possible but I'd say negligible. A typical champion golfer can drive a golf ball with a departure velocity of about 150 mph or so from the tee. That's fast but atmospheric drag quickly slows the ball down to around 50 mph or so by the time of impact back on the turf. Golfball drives from even the best athletes only gain about 90 feet of ...


6

This is an answer to a slightly different question: Could a golf ball damage an aircraft? The answer is yes, at least indirectly, as it has happened in 1987 in Benin. Basically, this golfer hit a bird with the golf ball. The bird fell into a fighter on takeoff with the canopy open (or hit the windshield, unclear). The pilot lost control of the aircraft ...


6

The MiG-29 series of aircraft are designed to operate from poor quality airfields, and for this reason, they feature separate air intakes for use while moving on the ground. See this article, including pictures of the aircraft: https://www.airforce-technology.com/projects/mig29/ Notice the additional louvre-shaped intakes on top of the aircraft's leading ...


6

What usually happens is the crew doing the walkaround spots something that looks like damage, calls airline maintenance, and techs come look at it. For a ding, they will consult the Structural Repair Manual guidance on allowable limits on dents. Based on the SRM it may be ok to leave as is, or require repair, or require further evaluation. If the SRM ...


4

If you are boarding with an engine running, it's going to be the one on the opposite side running with the one on the boarding side shut down. However, there's little doubt that items like that have flown off heads in high winds and drifted across to the opposite engine and been ingested, in all the millions and millions of flight hours over the decades. ...


3

Small, loose pieces, it sure could. But those are small flakes which would fit in your hands. Large chunks, it’s doubtful that the suction could lift them to ingest them off the runway. Now there’s a chance such a piece could get kicked up by the nosewheel of an airplane during a ground roll and thrown into the intake of an engine. Airports generally ...


2

I saw this yesterday: Samchui.com: Foreign Objects Discovered In Boeing 737 Max Fuel Tanks Included in the list of items discovered are rags, tools, metal shavings and other production equipment, which pose a serious safety risk in flight and on the ground in operational service.


2

Basically, atmospheric pressure is 14.7 psi and a jet engine functions as a vacuum. Given somebody else's postulate that a cubic foot of concrete weighs 150 pound per cubic foot and that an absolute vacuum exerts 14.7 * 122 == 2,116.8 pounds of pressure per cubic foot, it will blend... and fly... if it gets close enough to the jet intake. A jet engine won't ...


1

Probably very little. There's the very slight chance that it could stuck on a pitot tube or some other terrible scenario in a Final Destination type film which, coupled with another issue, could cause a problem but again very unlikely. The underlying hazard is the attitude towards FOD in general. It's a bad habit to build complacency towards any FOD sitting ...


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