Scud running and your minimums

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Atrosa
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Scud running and your minimums

Postby Atrosa » Tue Nov 19, 2019 3:19 pm

I know the 3sm rule and 500 ft rule under the deck but what is your personal minimums to go up there and not get into a CFIT situation. Is 3000 cloud cover reasonable for in the pattern work? Should I not consider if I'm in the pattern for establishing minimums? Would you change your answer if you were doing a 30 mile hamburger run? For arguments sake lets just say the metar and taf is OVC030 between you and you 30 mile destination. Thank you in advance for your wisdom.

3Dreaming
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Re: Scud running and your minimums

Postby 3Dreaming » Tue Nov 19, 2019 4:29 pm

I will take low clouds over low visibility anytime. For pattern work I use the legal minimum for when I'm training. Our airport has a class E transitions and a 1000 foot pattern, so I want a 1500 OVC for pattern work. I like to fly with students at least once with 3 miles visibility, just so they can really see how bad it is. Personally based on my local terrain I'm okay with a 2000 foot ceiling for going on a cross country, but I have thousands of hours flying tree top high doing pipeline and telephone cable patrols. When I was doing that 1 mile and clear of clouds wasn't unheard of. I would not do that in unfamiliar or hilly terrain.

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zaitcev
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Re: Scud running and your minimums

Postby zaitcev » Sat Dec 07, 2019 7:01 pm

I fully agree. I squeeze into "mail slot" readily as long as I can see the horizon, but I would never want to fly in a bowl where I cannot see. There may be precipitation or fog ahead, or a raising terrain.

Also, I'm big on the forecast trend. If it is forecast to worsen, and I need to beat it, I quit way earlier than if it's forecast on improvement.

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designrs
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Re: Scud running and your minimums

Postby designrs » Mon Dec 09, 2019 1:38 am

1) ALWAYS have a “SOLID GOLD” safe way out (alternative)
2) Use technology for increased situational awareness (e.g. Foreflight terrain features, ADS-B In/Out, in-flight weather map overlays, and flightplan for the greatest safety margins)
3) Know the area well (terrain, obstacles, and weather trends.) Don’t push marginal conditions in unfamiliar territory, or when you are fatigued.
4) Fly into IMPROVING weather conditions, NOT the other way around.
5) Learn good mountain flying techniques from an expert, if applicable for your area.
6) Train above your skill level with a really good CFI. Fly below your skill level when solo. Never stop learning.
7) Never give in to “get-there itis”
8) Understand FAA regulations AND the reasons for such regulations. Legal isn’t always safe.
9) Extra Fuel = More Options. Carry extra fuel as your weight, balance and aircraft performance allow.
10) Read NTSB reports, and other resources to understand how pilots die. “The Killing Zone” book is a good resource. Then use that knowledge to avoid becoming a statistic.

The TAF and METAR can be very misleading if there are changing geographical features along your route (such as water, grassy fields, desert, etc.)
- Richard
Sport Pilot
Ground Instructor
Previous Owner: 2011 SportCruiser

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designrs
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Re: Scud running and your minimums

Postby designrs » Mon Dec 09, 2019 2:56 am

There are so many factors that go into Aeronautical Decision Making (ADM) which depend on location, experience and equipment. I hope that at least a few items on the list above are helpful to you.

If you are simply doing pattern work, hopefully the airport is familiar to you, and you can always land if the weather is worse than expected. Seek guidance from experienced local pilots. Of course you are still subject to FAA regulations, and for good reason, especially if the airport has an instrument approach. You don’t want to be pushing the limits near the clouds when other aircraft are legally “flying blind” through the clouds on ILS approach to land.

A 30-mile burger run adds a bit more of a challenge.
Longer cross-countries require even greater consideration.
- Richard
Sport Pilot
Ground Instructor
Previous Owner: 2011 SportCruiser

chicagorandy
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Re: Scud running and your minimums

Postby chicagorandy » Mon Dec 09, 2019 8:56 am

With many of us starting to face Winter driving soon on the roads, it is worth double-noting #7 and #9.

7) Never give in to “get-there itis”

9) Extra Fuel = More Options.

Check road conditions and weather forecasts for your car trips too - getting caught on black ice and/or white-out conditions often leads to calamity. You can't always predict when the roads will get closed in front of you or conditions may put you in a ditch unseen. Without fuel your car can't make heat.

Stay safe out there.
"Don't believe everything you read on the internet" - Abraham Lincoln

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designrs
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Re: Scud running and your minimums

Postby designrs » Mon Dec 09, 2019 2:36 pm

Additional points to consider related to weather minimums:

11) Temperature Dew Point Spread: If the dew point spread is less than five degrees, fog can form. This typically occurs later in the day and around sunset. When the temperature falls, the dew point spread is reduced, causing fog to form, thus reducing visibility.

You generally want a minimum of a 5 degree dew point spread, and more than 6 points if leaving the pattern. An even greater dew point spread might be required in areas over or around water. (See the NTSB report of the fatal JFK Jr. airplane crash.)

On the other hand, if you were flying in the morning you might have the expectation of rising ambient temperatures to increase the dew point spread. This is why we often see the morning fog “cook off” as temperatures rise. Often ceilings will start to rise at the same time.

* So are conditions improving? Remaining the same? Or are they deteriorating?

12) Temperature and Altitude / Lapse Rate: At lower altitudes, the rule of thumb is that temperature decreases -2°C or -3.5°F for each 1000’ increase in altitude. So if you are at altitude and getting closer to those clouds, especially if there is moisture or precipitation, ICING can become another concern.
(I learned about this hopping over mountains in NY and PA on cold Winter days to visit Dr. Paul for maintence.)
- Richard
Sport Pilot
Ground Instructor
Previous Owner: 2011 SportCruiser

Atrosa
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Re: Scud running and your minimums

Postby Atrosa » Mon Dec 09, 2019 5:35 pm

These discussions and nuggets of wisdom make for safer pilots. Thank you everyone.


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