Simviation Forum - Why its important to preflight

Jun 24^th, 2007 at 5:54pm

Aerophile Offline
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Here are some snapshots of what a towbar can do to a wood prop if you leave the towbar on during takeoff. The student was preparing for his first solo cross country when a gust of wind came through and blew all of his charts off the wing. He ran across the tarmac to get his charts and forgot the towbar was still on. He then proceeded to taxi, runup, and takeoff. The towbar hit the prop on takeoff as the towbar was later found on the runway by another departing aircraft. The student claimed he didn't notice any engine trouble on takeoff so he continued 70 miles or so to his destination. He first noticed engine trouble after reducing power while approaching the airport. Fortunately the damage is only going to run 8 - 10,000 dollars. Had this been a metal prop there probably would be more damage to the engine as the wood prop absorbed most of the impact. This says a lot about those Sensenich wood props though. The towbar is perfectly fine, minus some griding from being pushed along the concrete, for those who might be concerned.

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Reply #1 - Jun 24^th, 2007 at 8:35pm

Ravang Ex Member

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Holy cow, how do you not notice that Shocked

, I would think that it would make a not so nice noise when it hit the towbar, this is why I don't use one Tongue

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Reply #2 - Jun 24^th, 2007 at 10:43pm

Brett_Henderson Offline
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Engine tear down and inspection Cry

plus parts, plus a prop.. Bet it'll be more than $10,000.

I'm just glad he's alive to learn from it

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Reply #3 - Jun 24^th, 2007 at 10:49pm

Willit Run Offline
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Ouch!! Bet he won't forget to check for the towbar again!!

&&

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Reply #4 - Jun 24^th, 2007 at 11:29pm

Aerophile Offline
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Brett_Henderson wrote on Jun 24^th, 2007 at 10:43pm:

Engine tear down and inspection Cry

plus parts, plus a prop.. Bet it'll be more than $10,000.

I'm just glad he's alive to learn from it

Actually our mechanics say that they'll be surprised if it did any damage to the engine at all. Since its a wood prop it absorbed a lot of the impact. The guy flew over 70 miles a didn't notice anything wrong until he brought the power back to low rpm. The vibrations he felt were likely due to the unbalanced prop. We found a local guy who will do the tear down for less than 8K. Of course we're going to have him replace oil rings and things of that nature while he's tearing it down. I think they said if they sent it to Continental it would cost nearly 20K or more. Had this been a metal prop it would have definitely done some damage to the engine as the metal prop wouldn't have absorbed much of the impact. But then again who knows. It could snowball into costing a lot more.

Not to long ago, an instructor and student inadvertently left the gear up in a Mooney during an attempted landing, only struck the prop, came back around, and safely landed with the gear down. He took about a 1/4 of an inch off of each blade. That one wound up being over 30K for the tear down and new engine. That one had just been overhauled too.

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Reply #5 - Jun 24^th, 2007 at 11:30pm

Mobius Offline
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Ouchies, at least he learned a good lesson, and he made a great example of why to check everything on the preflight for the rest of us.

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Reply #6 - Jun 24^th, 2007 at 11:35pm

Aerophile Offline
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Yeah, we added "check towbar" to the checklists of all of our aircraft and painted the towbars bright orange so that they're more noticeable. Wink

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Reply #7 - Jun 25^th, 2007 at 1:57am

expat Offline
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Hard to believe that no one saw this!! Sorry to ask, but his first solo, what was the instructor doing during this time. He should have been keeping at least one eye on his student. With the high/stress/apprehension of a first solo, that is the time a simple mistake could prove to be a little more consequential. I think the instructor also needs to be reminded of his duties here. Regardless of how competent you think your student is, a student is a student and will remain that for some time even after he has all the bits of paper under his belt. We never stop learning after all.

Matt

PETA People Eating Tasty Animals.

B1 Boeing 737-800 and Dash8 Q-400

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Reply #8 - Jun 25^th, 2007 at 7:24am

Aerophile Offline
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expat wrote on Jun 25^th, 2007 at 1:57am:

Hard to believe that no one saw this!! Sorry to ask, but his first solo, what was the instructor doing during this time. He should have been keeping at least one eye on his student. With the high/stress/apprehension of a first solo, that is the time a simple mistake could prove to be a little more consequential. I think the instructor also needs to be reminded of his duties here. Regardless of how competent you think your student is, a student is a student and will remain that for some time even after he has all the bits of paper under his belt. We never stop learning after all.

Matt

He was.

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Reply #9 - Jun 25^th, 2007 at 7:59am

Brett_Henderson Offline
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I'm sure the plane's owner knows what he's doing, and will do the math.

Since planes for hire need engine re-mans at 2,000(or sooner) hours, and 80% of that cost is labor.. there's a line of diminsihing returns. It might not have damaged anything internal but if there's more than a few hundred hours on the engine, ya gotta start thinking about doing a legit O/H when the engine is out and in pieces. It'll end up being cost-efficient over the long run (I know.. sometimes cash-flow today is more important to a plane owner.. but trust me.. cutting corners comes back to bite you in aviation... if there's an engine related accident a year from now.. you can bet your last do-nut that an insurance company will pay attention to the fact that a budget inspection was done.. they look for ANY reason to not pay)..

Engine reserve is built into rental rates, and the guy who did this must have insurance. If it were my plane, I'd pro-rate the rebuild and make his company pay for a full re-man.

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