Wingtip into Fence

[brien23]

Cessna 172M left wingtip ran into fence destroyed plastic wing tip, hit hard enough to bend pipe on chain link fence. Has anyone found secondary damage like rear spar, carry through or other places to look for secondary damage.

 

[Craig]

Check for buckling in the skins, binding of the aileron or flaps and bowing of the lift strut.

 

[GeorgeC]

Ask an A&P IA.

 

[xyzpdq]

Cessna 172M left wingtip ran into fence destroyed plastic wing tip, hit hard enough to bend pipe on chain link fence. Has anyone found secondary damage like rear spar, carry through or other places to look for secondary damage.

Check the rear spar behind the fuel tank for buckling.

 

[Magman]

As per preceding , check at the rear edge of the tank access panel.

You may ( hopefully you won’t ) see a bump about the center of that edge

if it’s a typical Tip Strike. Since the Rear ( aka False ) Spar is only .032 or .040

thick it will likely buckle if the Plastic Tip is damaged.


It may be wise to open some inspection panels and squirt the protruding screw

threads with your favorite penetrating oil. There are various methods to remove

the difficult screws; my preference uses a Rivet Gun.


At once time Cessna sold a Rear Spar Repair Kit which addresses the repair

perfectly. The last one I used was very difficult to find. EARLY Cessna Service

Manuals include the repair but some later ones have it crossed out.


Whoever is doing the repair should verify correct “ Wash- out” using the simple

tools in the Sheet Metal Repair section of the SM.


Some Tip Strikes tend to be overlooked and a full post- strike inspection is

not performed. I know of a 150, Cardinal and an Archer that were flown BEFORE

discovering the extant of the damage. Likely because the Plastic Tip was still

intact. The Archer tore out the forward Attach Point so the still installed wing

could actually be moved. The Cardinal fuselage was buckled.

 

[Racerx]

As per preceding , check at the rear edge of the tank access panel.

You may ( hopefully you won’t ) see a bump about the center of that edge

if it’s a typical Tip Strike. Since the Rear ( aka False ) Spar is only .032 or .040

thick it will likely buckle if the Plastic Tip is damaged.


It may be wise to open some inspection panels and squirt the protruding screw

threads with your favorite penetrating oil. There are various methods to remove

the difficult screws; my preference uses a Rivet Gun.


At once time Cessna sold a Rear Spar Repair Kit which addresses the repair

perfectly. The last one I used was very difficult to find. EARLY Cessna Service

Manuals include the repair but some later ones have it crossed out.


Whoever is doing the repair should verify correct “ Wash- out” using the simple

tools in the Sheet Metal Repair section of the SM.


Some Tip Strikes tend to be overlooked and a full post- strike inspection is

not performed. I know of a 150, Cardinal and an Archer that were flown BEFORE

discovering the extant of the damage. Likely because the Plastic Tip was still

intact. The Archer tore out the forward Attach Point so the still installed wing

could actually be moved. The Cardinal fuselage was buckled.

Wonder if that archer would have passed the Eddy current inspection for the spar bolt holes...

 

[Magman]

The Archer presented entirely different from the others.

With the Forward Attach torn out ( as in “ Bearing”) you could move the wing a

small amount. The real surprise here was finding the baggage compartment floor

buckled! I’m sure it would have additional loads on the spar holes.

Note that the Airframe Components website has some excellent short vids on

topics like this. Sorry; a link is above my pay grade.


Note: I just checked their site and it has been revised. It appears you must click on

You tube channel to see the full list.

 

[frfly172]

A thorough by someone who is familiar with the airplanes would seem to be in order. Find an IA you are comfortable with using.