Real world icing advice

[Seth]

Tom,

They are very good about letting you do what you need in the Pacific Northwest. That is a very well known area for icing. Cold, moist air! It does get annoying though because they typically over forcast the icing conditions to be worse. There are a few times that I took off with an out and didn't get any icing at all. I also learned to call Seattle from the remote frequency and ask for PIREPS about tops, icing etc. Then I would wait for a reply back via handheld. It's sad how few pireps are given even during bad conditions. If only everyone would do a pirep about weather it could help pilots that are trying to make the go/no go decision. Often when I am on a cross country with weather conditions I give pireps every 30 minutes or so....and after a flight I can look and see a trail of PIREPS!

 

 

You know you are right.  I try to give PIREPS more often and don't often do it myself.  That's a good idea - to give PIREPs every 30 min or whenever you clear a cloud base, have any sort of condition or if conditions look odd, but are smooth.  We should all give more PIREPs. 

 

-Seth

[tomn]

Your alternate air door is located on the back of the air filter box on the inside of the cowling. It has a flap that has a spring attached in the center that is seated on the back of the air box. When the filter gets clogged (snow, ice, etc.), the vacuum inside the air box will increase and eventually pull the door open allowing air in to keep the engine running. You can check it like Chris said by pushing on the post that the spring is on. I'll try to take a picture of it and post if someone doesn't beat me to it.

[Marauder]

Your alternate air door is located on the back of the air filter box on the inside of the cowling. It has a flap that has a spring attached in the center that is seated on the back of the air box. When the filter gets clogged (snow, ice, etc.), the vacuum inside the air box will increase and eventually pull the door open allowing air in to keep the engine running. You can check it like Chris said by pushing on the post that the spring is on. I'll try to take a picture of it and post if someone doesn't beat me to it.

Thanks for explaining it Tom. It gets overlooked a lot, just like the Ram air boot.

[M016576]

The last legal interpretation I could find was from Jan 2009 which Bruce mentions in his write up.

Yep, I was referring to the IFR magazine article you posted before the FAA letter, sorry, I should have been more specific. The date on all the IFR magazine articles online reads whatever today's date is: it's a bit of a spoofer. During the time when that article by Bob Miller was written (2006/2007) (and when I was going through Navy pilot training in 2001), icing meant freezing and any visible moisture. Now, due to that 2009 letter, the rules are a bit looser and open to interpretation a little bit. So flying in subzero temperatures in visible moisture (while maybe not smart), isn't necessarily illegal... For most of us, it doesn't change much, but for those with turbos and/or TKS de-ice (not FIKI'd version), it certainly gives them much more opportunity to fly without the worry of being violated.

[tomn]

Thanks for explaining it Tom. It gets over looked a lot, just like the Ram air boot.

Ram air boot...what's that? Glad you mentioned it Chris - have not looked at that in a while...

[jetdriven]

I know from personal experance that you need to close the ram air door if you are in the clouds. Everything you have been taught about fuel injection not icing up is wrong. The RSA-5 will get leaner and leaner until the engine quits when it gets iced up. BTW it thawed out before I got to the ground. It is very unnerving having a dead engine in the clouds.

 

Be vary carefull flying into icing conditions with a big tail wind. By the time you decide you have too much ice and it is time to turn around, you will be flying in the icing much longer on the way out.

 

That happens quite often to Mooney pilots.  Those 4 air sense tubes ice up in the fuel injector servo with ram air open and in many cases the engine just smooth shuts down cold.

[John Pleisse]

The Ovation crash in West VA was a horrific example of induction icing.

[aviatoreb]

The Ovation crash in West VA was a horrific example of induction icing.

 

I don't remember that one - can you link to the NTSB report please?

[carusoam]

Alternate air source is a checklist item on the R. A push/pull of the rod from within the cabin will let you know it is working.

Best regards,

-a-

[kmyfm20s]

http://www.aircraftdatasource.com/index.php?option=com_content&view=article&ev_id=20061220X01818&id=113

While it seems logical that it was induction ice, I could also see the possibility of fuel contamination with water that froze. It sounds like its a manual as well as automatic by pass for the induction system but I don't have an Ovation so I don't know for sure. If it has an automatic by pass like my 201 and still was deemed the cause of the crash, that concerns me.

[carusoam]

The O has an automatic gate, it is held shut magnetically.

Best regards,

-a-

[John Pleisse]

I can't recall the exact NTSB finding, Erik, but is sure has been disseminated in Mooney and GA circles as induction icing. There is also a 231 accident in the Sacramento, CA area that involved induction icing, but this is going back a number of years.

[Cruiser]

from the accident report: "Several engine start attempts were made, with restrictions in a number of fuel supply elements found. After cleaning the elements, the engine was started, and the throttle was advanced to full open where it maintained 2,750 rpm for 5 minutes. The throttle was advanced from idle to full six times, with no hesitation, stumbling or interruption noted."

 

This was in a test cell at the engine manufacturers lab? It would seem the restrictions , whatever that means, kept the engine from starting.

[aviatoreb]

Thanks N435H.  Yeah - scary stuff.

 

Cruiser, I am surprised to hear that they could start the engine from an airplane wreck where the farmer who was first on the scene described an explosion, and fireball and a burning aircraft he approached.

 

Probably induction icing, but otherwise could it be fuel starvation due to icing of water in the fuel delivery from the tanks?

 

If induction icing, I wonder why the automatic alternate air failed to work, and anyway I wonder why the NTSB did not seem to comment on this critical element that could be an important data point for others with a like system.