go, no-go decision - only LIFR en route

[rbp]

2 hours ago, cliffy said:

Cave diving solo? That's the most gutsy thing I've ever heard.

 

 

every tec dive is treated as a solo dive. other participants are called "team members" not "buddies"

[cliffy]

How long could you suck pure O2? I would think (as I was taught in aviation ) that pure O2 at elevated pressure is toxic after a short period.  I only go back to the written tables for diving never had a computer but an aluminum  72 tank (IIRC) and Conshelf regulator.  Went to 100 ft once just to say I did it. 

[rbp]

7 hours ago, cliffy said:

How long could you suck pure O2? I would think (as I was taught in aviation ) that pure O2 at elevated pressure is toxic after a short period.  I only go back to the written tables for diving never had a computer but an aluminum  72 tank (IIRC) and Conshelf regulator.  Went to 100 ft once just to say I did 

50% 80% and 100% are the most common decompression gasses, with maximum operating depth of 70, 30, and 20' respectively. Most tech diving watches will track accumulated exposure to oxygen, so you don't have to, and display it as a percentage of acceptable exposure. one OTU is equal to breathing 100% O2 for 1 minute at 1 atmosphere. 

[cliffy]

OK Now that makes sense Thanks1

[amillet]

On 11/30/2022 at 2:29 PM, Hank said:

Please tell me more about this! I know some people that I want to give it a try . . . .

My niece actually worked as a big cat trainer/keeper at facilities in WA and AZ before working briefly with Siegfried and Roy in Las Vegas. She quit not long before Roy was mauled by the tiger

[Ragsf15e]

42 minutes ago, amillet said:

My niece actually worked as a big cat trainer/keeper at facilities in WA and AZ before working briefly with Siegfried and Roy in Las Vegas. She quit not long before Roy was mauled by the tiger

That tiger peed on me once.  I was at the mirage, checking them out and it just turned and doused me.  Had to get back to my hotel and shower. Never trust a tiger.

[1001001]

On the same day you posted this, I was supposed to fly from western PA to the Gulf coast (MS).  I was planning to leave at about 0700, which would have allowed me to get up above an IFR (not low) layer to the west of the Appalachians and skirt the edges of it until southern Tennessee, where it would have cleared up.

I got to the run-up pad and wouldn't you know it, Cylinder #2 was totally dead on the left magneto.  I taxied to a local shop and between them moving airplanes around inside their crowded hangar and other things, it was 3 hours later that we had diagnosed and replaced a bad lower spark plug, recowled, tested, and test flown around the pattern.

At this point, I checked the weather again, and what had been a thin broken layer just to the south of the airport had become a solid overcast of indeterminate thickness, with temperatures in the freezing range, for about 100 miles south of my start point.

I technically had the option to file an IFR plan starting at a fix at the southern edge of the overcast and go VFR underneath, but it would have forced me to fly lower than I'm comfortable with, and some of the airports along the way were then reporting LIFR conditions, which would constrain my options in both vertical directions.

I made the decision not to go based on:

1.  Unknown layer thickness and probable icing inside it (Garmin Pilot's icing model is very useful here)

2.  Constrained options for VFR under the layer, with limited airports with approachable weather.

I ended up missing some important stuff for work (because I couldn't get a commercial ticket in time to make my appointed time), but it's better than being a statistic balled up on the side of a hill in West Virginia.

[rbp]

3 minutes ago, 1001001 said:

but it's better than being a statistic balled up on the side of a hill in West Virginia.

one can survive a crash, but more difficult to survive the Monday morning quarterbacks on mooneyspace

[1001001]

10 minutes ago, Evan said:

Something I know use for IFR and even VFR is the Skew-T. While you can't 100% determine the tops you can get a general idea. There are some good videos online on how to use it. 

Here is a link to view them: https://rucsoundings.noaa.gov/

Here is a training website on how to use them: https://www.avwxtraining.com/home

Skew-T is definitely useful.  I attended a presentation a few years ago on it given by our local National Weather Service office.

[1001001]

Just now, 1001001 said:

Skew-T is definitely useful.  I attended a presentation a few years ago on it given by our local National Weather Service office.

For those that aren't familiar, local NWS offices will usually work with you to have a meteorologist visit with a group and present on weather topics of interest.  If you have a local IMC Club, EAA chapter, or other aviation group (or even Scouts or other children's org), they'll usually be happy to do a presentation.

[Marauder]

On the same day you posted this, I was supposed to fly from western PA to the Gulf coast (MS).  I was planning to leave at about 0700, which would have allowed me to get up above an IFR (not low) layer to the west of the Appalachians and skirt the edges of it until southern Tennessee, where it would have cleared up.
I got to the run-up pad and wouldn't you know it, Cylinder #2 was totally dead on the left magneto.  I taxied to a local shop and between them moving airplanes around inside their crowded hangar and other things, it was 3 hours later that we had diagnosed and replaced a bad lower spark plug, recowled, tested, and test flown around the pattern.
At this point, I checked the weather again, and what had been a thin broken layer just to the south of the airport had become a solid overcast of indeterminate thickness, with temperatures in the freezing range, for about 100 miles south of my start point.
I technically had the option to file an IFR plan starting at a fix at the southern edge of the overcast and go VFR underneath, but it would have forced me to fly lower than I'm comfortable with, and some of the airports along the way were then reporting LIFR conditions, which would constrain my options in both vertical directions.
I made the decision not to go based on:
1.  Unknown layer thickness and probable icing inside it (Garmin Pilot's icing model is very useful here)
2.  Constrained options for VFR under the layer, with limited airports with approachable weather.
I ended up missing some important stuff for work (because I couldn't get a commercial ticket in time to make my appointed time), but it's better than being a statistic balled up on the side of a hill in West Virginia.

You definitely made the right call on this flight. I’m familiar with the weather northwest PA can throw at you and stacking the odds in your favor will keep you from becoming a lawn ornament.


Sent from my iPhone using Tapatalk Pro

[A64Pilot]

On 12/4/2022 at 1:07 PM, cliffy said:

How long could you suck pure O2? I would think (as I was taught in aviation ) that pure O2 at elevated pressure is toxic after a short period.  I only go back to the written tables for diving never had a computer but an aluminum  72 tank (IIRC) and Conshelf regulator.  Went to 100 ft once just to say I did it. 

We leave the O2 bottle in the mouth of the cave, no deeper that 20 feet, deeper than 20 ft O2 is toxic, many deaths have occurred from accidentally breathing from the wrong bottle, more than you would think, often open water diving. it’s possible to confuse regulators when you have several, so as we HAVE to come out the way we went in almost always, it’s best to leave the bottle, open water diving you take your deco bottle with you because it’s possible for you to come up someplace not planned.

Tri-mix diving three gas mixes are common, almost all my cave diving I only had one gas mix with me in the cave, most Fl caves are relatively shallow, some of course are not.

[cliffy]

I have some friends (2) with way over 3000  dives each and they occasionally do mixed gas dives.  

[T. Peterson]

FWIW, I think you exercised very good judgment. There is no fail safe. It can be a beautiful VFR day and if the engine seizes at 200 feet on takeoff, you don’t have a lot of outs.

What I don’t think you can do is adopt every posters bad experience as your own and make yourself miserable with “what ifs”. I am NOT saying don’t learn from all these folks. I am grateful for the aggregate wisdom and experience on this forum, but you must come up with your own personal minimums. Use the experience here to inform but not to form.

A lot of fellas here would not have done what you did, but what you did was thoughtful and contemplative. I will also bet you experienced a real sense of accomplishment after that trip. That’s what gives life spice. 

[jlunseth]

I will modify what level of risk I take depending on whether I am carrying passengers or not. It’s not what you think. It’s not “it’s ok if it’s just me, but I don’t want to risk someone else’s life.” What I always think about is that single exit door. Getting one person out (me) who is trained is not so bad, getting two or three out and the rest being untrained and probably freaking out would be a nightmare.

[hais]

On 11/29/2022 at 7:06 AM, ilovecornfields said:

That video is 1:26. Any chance of getting the TL:DR? Having it in real time as part of the engine analyzer would be ideal.

Not exactly a summary you asked, but here's another long one on the topic