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Question

Would a golf ball ingested into an engine, or impacting a windshield cause meaningful damage to a commercial airplane?

The scenario below outlines that this is possible, but the principle question is: would it actually matter, as in, would it cause the same level of damage as, say, a strike from a single bird?

Plausible Scenario

At McCarran airport in Las Vegas (KLAS), runway 1R is situated just across the street from a driving range. Several years ago, I was hitting balls on this range when a 747 landed on 1R. It seemed impossibly low; many people on the range stopped hitting to point and take pictures. For context, here's a video (not mine) taken from nearly the exact same spot, with an approach to the same runway.

At the time, I remember thinking "That plane is very low... what if it got hit?" Appearances are often deceiving, so my initial assumption was that it must be higher than I thought, so a did a bit of basic trig to find out:

The touchdown markers on 1R are about 4,250 feet (red line in picture below) from the top-level hitting stations. With a 3 deg. glide slope, the plane would have been roughly 225 feet above the ground when passing over the driving range (slightly lower down range when balls that have been hit are at their highest point).

KLAS_1R_golfrange

(Image: Google Earth; own drawing)

With a 21-degree 7-wood which I hit about 200 yards, the ball would reach an apex of around 230 feet.

So, wind, timing, and the quality of golf shot actually struck notwithstanding, it seems at least possible that a ball hit from off that range could hit an airplane. In other words, the "bounding box" of the plane at least theoretically intersects a line representing the maximum height of a shot from the driving range. Thus, it seems unsafe, even if the chance is 1:1,000,000 (or greater).

I have to assume that since KLAS is one of the busiest airports in the U.S., that this is not actually an issue, otherwise changes would already have been made.

However, if an impact or ingestion were to occur, are there circumstances where it would be a "significant" event?

Notes

  1. No one, esp. myself, was trying to hit the plane.
  2. Despite #1, there are at least 50 hitting stations, which means lots of shots in the air as the plane is passing over the range.
  3. This is Vegas, and alcohol is served at that range. People do try, sometimes, to hit the guy in the little range car. I doubt that would ever carry over to a plane, but it can't be logically ruled out.
  4. My concern is that even without anyone trying, a ball could still impact the plane. But would it matter?
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    $\begingroup$ There is Golf Course between 2 runways of DMK airport $\endgroup$ – Him Dec 31 '17 at 8:57
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    $\begingroup$ Very interesting question! Couple of thoughts: by the time you see an aircraft in front of you, your golf ball may have a hard time chasing down & catching a 150~ mph jet. What sort of velocity can you get on a drive like you describe? Also, at least 1, maybe both, of the north runways in LAS have steeper-than-standard approach angles. I’ll have to check which; this could be the reason. A golf ball thru the core of a motor would certainly be bad for it. Very interesting question - well done indeed! $\endgroup$ – Ralph J Dec 31 '17 at 9:27
  • $\begingroup$ Scratch that theory... the RNAV approach to 1R is a 3 degree angle. It’s the ILS 1L that is 3.4 degrees. So they didn’t change the approach based on this situation. For any single flight, it’s a pretty unlikely “golden bb”, but with enough flights (and enough golf balls)... $\endgroup$ – Ralph J Dec 31 '17 at 9:36
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    $\begingroup$ Most definitely the latter. Not that a full accident would result from impact, I think, but to have such a large plane go directly overhead while you’re hitting is stunning. For me at least an initial thought was “this does not seem safe!” $\endgroup$ – Dan1701 Dec 31 '17 at 16:07
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    $\begingroup$ Not that it says much, but golfing is prohibited at the famous Myrtle Avenue spotting location next to London Heathrow by a dedicated sign posted there. Could be to protect cars on nearby A30, not aircraft, though... $\endgroup$ – Cpt Reynolds May 3 at 22:23
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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 that the engines had been tested for water and hail ingestion at cruising speed... not at near idle, which was the power setting during a descent. Once identified, that problem was rectified quickly with mods to the engines.

Nor does the golf ball have the sheer mass of a goose, such as the flock of geese that took out both engines of USAir 1549.

Most likely, a golf ball striking a running turbofan would be sliced up by the front fan, and centrifugal force would tend to fling the fragments outward where they would exit via the bypass, and not through the turbine engine.

So I'd have to say, very unlikely, only to allow for the chance in a billion that the sliced up fragments of a golf ball might actually enter the compressor stage and cause a problem in one engine.

The greatest problem from a golf ball being ingested by a turbine, is figuring out what rule of golf applies... how do you mark your card? (WTF probably doesn't meet approved guidelines)

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    $\begingroup$ I think it's fair to say then that one golf ball sucked into an engine wouldn't be significant damage. Thanks! As for golf, I'm pretty sure you'd proceed under Rule 18-1, so the airplane-shot would be cancelled and you'd play again from the same spot. $\endgroup$ – Dan1701 Jan 8 '18 at 6:17
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    $\begingroup$ I dispute the part that ice is denser than golf ball. Ice I see always float but whenever my golf ball goes to the water it always sink. $\endgroup$ – vasin1987 Jan 8 '18 at 11:16
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    $\begingroup$ good point... perhaps it's fair to say that ice is harder than a golf ball, and thus more likely to produce damage if struck by a moving fan blade. $\endgroup$ – tj1000 Jan 8 '18 at 17:08
  • $\begingroup$ Not Rule 11.1? You don't think the ball needs to be played from the gate after the airliner has landed? ;-) $\endgroup$ – Dannie May 3 at 8:55
  • $\begingroup$ Smarter Every Day just published a video on how hard you can hit a golf ball. It turns out golf balls are incredibly strong, so I'm not sure it would be 'sliced up by the fan'. I suppose realistically the only solution is to buy the Smarter Every Day guy a turbofan to test it. $\endgroup$ – Sanchises May 3 at 9:35
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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 altitude during a typical drive, making it highly unlikely that that a drive could launch a ball to even the ILS decision altitude of 200 feet AGL. With a typical jetliner flying an approach at 140 knots (161 mph), it's highly unlikely that a golfball could catch up to the aircraft in flight as well.

But even if you cold drive a golf ball with a herculean effort, as any anti aircraft artillery gunner will tell you, it's extremely difficult to hit a moving aircraft using unguided fusillades. Golfers have enough trouble aiming for a putting green, taking into account position, obstacles, winds, etc. to have to add in the additional difficulty of hitting an airborne and fast moving object as well.

Now should a golf ball hit an airplane, yes there is a change to damage it similar to an errant drive hitting a car. Superficial dents or scuffs would be anticipated. It might damage an aircraft window, though I highly doubt it would shatter, particularly windows on pressurized aircraft. Golf balls ingested into engine intakes and or propeller arcs would be pretty hazardous for the aircraft as well.

So who knows, maybe someone here can dig up a wild story from the past where a golfer nailed a low flying 707 with a drive and took out an engine, but I highly doubt it's possible and really not even a risk at that distance from the airport.

Now a pilot with an engine failure shortly after takeoff and makes a forced landing onto a golf course, only to have an ill tempered golfer fire a drive at his airplane out of ire, that's another possibility.

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    $\begingroup$ The question appears to ask "Can a golf ball do damage?", not "Could a golfer hit an airplane (from this spot)?". $\endgroup$ – Bergi Dec 31 '17 at 11:12
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    $\begingroup$ I'm not sure why a golf ball would have to catch up with the airplane, in the same way that birds don't have to catch up to be stuck by an airliner. Besides, the golf course is about 600m from the runway threshold, so chances are that the airliner is already below DH (and why should DH matter at all?) $\endgroup$ – Sanchises Dec 31 '17 at 11:46
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    $\begingroup$ But the course is about 1 km from the touchdown markers of the runway and the glide slope antenna, which would correspond with approx a 200 ft height for the jet on final approach, clearly out of range for even the best golfers. $\endgroup$ – Carlo Felicione Dec 31 '17 at 16:52
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    $\begingroup$ It would be incredibly tough to hit a plane with any given shot. I think the premise of the question is not an intentional strike, but just the fact that there are hundreds of planes and hundreds of balls in the air in close proximity and potentially there is an accident there. $\endgroup$ – Thomas Dec 31 '17 at 22:26
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    $\begingroup$ @Thomas Yes, that's exactly what I'm saying. $\endgroup$ – Dan1701 Jan 7 '18 at 3:56
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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 and subsequently collided and destroyed several other planes on the apron.

Refs:

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  • $\begingroup$ I hope this isn't some kind of urban legend... $\endgroup$ – kebs Jan 8 '18 at 5:32
  • $\begingroup$ What are the chances :D $\endgroup$ – Jan May 3 at 6:24
  • $\begingroup$ I have to object here. It is grossly misleading to say the golf ball damaged an aircraft when in fact it destroyed or damaged the entire air force. LOL, thanks for this. $\endgroup$ – Ville Niemi May 3 at 10:08
  • $\begingroup$ Spectacular. Thank you for sharing! I'm sure it must be true. $\endgroup$ – quiet flyer May 5 at 20:02

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