Squeaks in the 170

How to keep the Cessna 170 flying and airworthy.

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Squeaks in the 170

Postby ghostflyer » Thu Mar 05, 2020 5:57 am

When a 100 holy inspection is carried out ,I am sure that a detailed inspections are not carried out inside the fuselage where the engine frame mounts are bolted to the fire wall . There are fittings that can have exfoliating corrosion . These fittings are riveted to stringers that run horizontally along the airframe . The stringers can also crack or corrode that not very obvious with a torch and mirror . The only indication that you will get when some thing is not right is when the skin of the fuselage in this area appears cracked or smoky rivets . We had a issue like this very recent on a Cessna 172 b series and a 172 R series . However a quick and easy way to check your mounts is use a stethoscope on the effected area and have some one gently rock the spinner around [not turning the prop] . You will hear crackling noise or noises [squeaks] coming from that area indicating movement .
There was a Cessna 172r series and it was used as a instructional example when one guy eyes lit up saying he could here noises . YEA sure !!. It was a good laugh until some one else picked up the stethoscope and had a listen . It had a broken fuse large mount . It couldn’t be seen due to the oil and dirt and bits of sound proofing .
A mic place against the fuselage and a amp can be used instead of a stethoscope.
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Re: Squeaks in the 170

Postby gahorn » Thu Mar 05, 2020 7:18 am

Unfortunately, using the spinner to attempt movement of the engine can lead to expensive damage to the spinner dome and bulkhead. I’d advise some other method to stress the engine mounts.
'53 B-model N146YS SN:25713
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Re: Squeaks in the 170

Postby ghostflyer » Thu Mar 05, 2020 11:52 am

You only put a soft pressure on the spinner ,back and forth with open hands Do not attempt to move the engine via the cowls . They give false noises and lack of engine frame movement.
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Re: Squeaks in the 170

Postby gahorn » Thu Mar 05, 2020 1:15 pm

Why wouldn’t you confirm the mags are Cold and grab both prop-blades at the hub and give it a shove? (Not actually turn the prop, only rock the engine around.)
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight.
An originality nut (mostly) for the right reasons. ;)
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Re: Squeaks in the 170

Postby ghostflyer » Thu Mar 05, 2020 11:04 pm

Only a gentle “shove” is that are needed. Giving a heavy shove often will start a squeak from the windshield /wing area and cowls or from the undercarriage area. I have a Cessna 182 that has a squeak from the left hand fairing on the undercarriage .initially I thought it was a loose attachment bolt but found it was the fairing moving against the fuselarge .
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