Navajo De-Ice Boots

[Downtown]

As some of you may know, many Navajo's have de-icing boots on the leading edge of the wings just from the engine nacelle to the wing tip. The leading edge of the wing from the engine nacelle to the fuselage is often unprotected. My question is, does anyone know if this means flight into known icing is prohibited?

Downtown

[. .]

This is 100% second hand talk.

I had heard that only PA-31-350s with the full wing boot were certified into known icing. I can't speak for the smaller Navajo's in the family. I'm certainly someone will have a link, or more definite answers for you. It would seem mighty strange for so many Navajo's to be out there flying without the boots, if it were to be illegal.

[Canoehead]

I seem to recall that the Ontario MOH required PA31 (medevac) operators to have the full leading edge protected to be used for MOH work. I think that some did mods for their airplanes to qualify. Not sure that it was necessarily required for flight into known ice other than that.

I could be waaaay wrong though... it's been a while.

[iflyforpie]

Apparently certain serial numbers of all models of the PA-31 are certified for flight into known icing provided they are equipped as per Piper drawing/equipment list (Certification Basis, Page 11/12). Looks like 1980-83 310/325s and 1980-85 350s. 1976-79 350s can be modified for known icing.

http://www.airweb.faa.gov/Regulatory_an ... /A20SO.pdf

[flyguy1980]

I'm currently flying for an operation with 4 navajo's. Two are PA31-350's with boots on the leading edge between the fuselage and the engine, one without, and a PA31-310 without boots on the inner wing. We are legal to fly into known ice, in all of these airplanes. Hope that helps you out.

[Labour Board]

as I recall its more to do with the Serial #, the stall warning heat, and the year manufactured in regards to the certification (prior to 197? aircraft didn't need certification for FIKI?) than the boots, but I could be completely wrong.

[nookie201]

Interesting study done on various aircraft by US institute of Aeronautics, they compiled a database of small twin piston in-flight icing related accidents between 1978 - 2002

For every 40 400-series cessna icing accidents, there was 1 PA-31 related icing accident.
Now there's approx 30% more 400 series A/C known to be flying but still!.

PA-31 seem to hold its own in icing.

My 1976 PA-31P POH states, certified for flight into light and moderate icing.

-G

[bbb]

It is all according to type certificate and what the AFM says. The earlier (1973? 1972? onward) PA31-310 state ok for flight into light and moderate icing, although the required equipment was an option. I believe the earliest PA31 may not have (late 1960's). PA31-310 and -325 did not have the inner boot, only the -350 (chieftain) does, nor is it required for known icing. Make sure however that the aircraft is equipped with functioning equipment as stated in the AFM. Ontario TC had questions about 15yrs ago, trying to say that the -310 wasn't authorized for known icing, due to the fact that it didn't have full leading edge protection as the -350 does, however a quick copy of the type certificate, and appropriate pages from the AFM including equipment lists, put an end to that.

As for what Nookie provided, yes, HUGE difference in the 400 Cessnas vs PA31 series in icing. Take a look at the wing section - the Cessna is much thiner. Be aware if you've only had experience in icing with the Piper twins (pa-34,esp pa-31 and pa-23) and start flying the Cessna. no one should be flogging around in icing for any length of time at all, but with the Cessna's, what wouldn't have been a big deal in the Piper will be a VERY big deal in the Cessna. I've had to hold almost full power to maintain glideslope at the latter part of the approach. There would be no option to go around/missed approach. And this is only picking up ice during the approach, it was clear above. An engine failure during the latter part of the approach would have likely meant landing short of the runway.

I believe flight in icing was got into in some depth on another thread that I can't seem to find right now, where some of the very experienced folks here posted some great info, in regards to an obviously inexperienced person's take on icing and flight. If someone else can find it and post the link.... its serious stuff, no matter which aircraft you fly. And we're not out of "the season" yet.

[Navajo Flyer]

The best way is to check the equipment list and then check the flight manual. Pre 1980 Pa-31's weren't certified for flight into "known" ice. Yes the earlier machines had the option of deice boots, but when istalled they were approved for flight in icing conditions - light to moderate. The navajos after 1980 had the boots on the inboard sections, if installed, of the wings and were certified for flight in known icing. There is a fair bit of difference between the two. On the known ice machines the wings will inflate first for 6 seconds then the tail section will then inflate for 6 seconds.

[Downtown]

Thanks so much to everyone for all your input. It was very helpful!

Downtown