### Objective Background knowledge required for safe mountain flying. ### References - [[Mountain Flying Bible]] - [[Mountain Flying]] - [[Aviation Weather Handbook]] Ch. 16 - [[FAA-P-8740-2 Density Altitude]] - [[Oxygen Equipment Use in General Aviation Operations]] ### Resources - [[FROM THE ARCHIVES - Mountain Flying (1991)]] - [[Back to Basics - Tips to Mountain Flying]] and [[Tips on Mountain Flying]] - [Mountain Flying & High Density Altitude in 57 Seconds](https://www.youtube.com/watch?v=k1qylDKtr6M) - [Mountain Flying](https://www.aopa.org/training-and-safety/online-learning/safety-spotlights/mountain-flying) from [[AOPA]] - [Backcountry Resource Center](https://www.aopa.org/training-and-safety/air-safety-institute/backcountryresourcecenter) from [[AOPA]] ### Builds On - [[PPL1.1 Aircraft Preflight, Taxiing, and Postflight Procedures]] - [[PPL4.5 Advanced Weather Briefs and Preflight Planning]] - [[CPL.12 High Altitude Operations]] ### Schedule Ground 2.0 hr ### Lesson Elements #### Mountain Flying Theory 1. What counts as mountain flying? > [!quote] From [[Tips on Mountain Flying]] > Rather than offer a definition of "mountain" flying, it should be pointed out that many of the subjects discussed in this publication can be found in nonmountainous areas or at low altitudes. For example, density altitudes over 8,500 feet can be found regularly on the eastern plains of Colorado in the summer. Also, dangerous mechanical turbulence and even mountain wave can be found in areas that aren't usually considered mountainous. 2. Basic Premises of Mountain Flying > [!summary] From [[Mountain Flying Bible]] > 1. Always remain in a position where you can turn toward lowering terrain. > 2. Never fly beyond the [[point of no return]]. 3. Preflight Considerations 1. Pilot 1. Aeromedical Factors 1. [[Hypoxia]] 1. [[Oxygen Systems]] (legal, practical, and at night) 2. [[Dehydration]] 3. [[Fatigue]] 4. Impact of sinus issues at altitude 1. Valsalva maneuver 5. #Illusions 2. Equipment 1. Survival 1. Air Search and Rescue won't begin until daylight; chances are good of spending at least one night outdoors 2. [Striving to Survive](https://www.faa.gov/pilots/training/airman_education/topics_of_interest/survive) has a good list of equipment to consider 3. Priorities and survival techniques 4. [[PLB]]s 2. Enroute 1. Pulse oximeter 2. Water 3. Oxygen bottle 3. Periodic Self Checkins ([[IMSAFE]]) 4. [[Personal Minimums]] 2. Aircraft 1. Performance at High [[Density Altitude]] 1. Be wary of [[Hot, High, and Heavy]] 2. Takeoff/Landing Calculations 1. [[50-70 Rule]] 2. Higher [[TAS]] and [[GS]] on landing, same [[IAS]] 3. Impact of downslope, grass, etc^[[[AC 91-79]] has more info on this] 3. Climb performance degradation 1. May require circling to gain altitude ([[Shuttle Climb]]) 2. May not be able to out climb [[downdraft]] (best to push forward out of it, similar to ocean riptides) 4. Power and performance impacts 1. Power in normally aspirated engines decreases 3% for every 1000'^[From [[Mountain Flying]]] 5. [[Service ceiling]] consideration 1. Remember that Vx and Vy converge at higher altitudes ([[Vx vs Vy at Higher Altitudes.svg|image]]) 6. Extrapolating from performance data 2. Selecting an aircraft for the mission 1. Some experts recommend that 160 horsepower should be considered the absolute minimum for the airplane, especially when the pilot lacks significant mountain flying experience. 3. Weight & Balance considerations 1. 90% of [[MGW]] recommended 2. Impact of fore and aft [[CG]] 4. Equipment 1. Best to test [[ELT]] before departing (More info from [[AOPA]] [here](https://www.aopa.org/news-and-media/all-news/2017/february/flight-training-magazine/how-it-works-elt#:~:text=You%20can%20test%20your%20121.5,the%20first%20order%20of%20business.)) - average time to find down aircraft with ELT is 6.8hr, compared to 40.7hr without^[https://www.faa.gov/pilots/training/airman_education/topics_of_interest/search_rescue] 3. Environment 1. Account for [[Density Altitude]] 1. > [!quote] From [CFI on Reddit](https://www.reddit.com/r/flying/comments/okujin/comment/h5aldtx/?utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button)^[So take it with a grain of salt] > Remember the things you can do to help reduce the effects: **weight** (reduce pax/baggage), **wait** (for the temperature to decrease), **wait** (for winds to increase), and **lean**. 2. Time of day 1. Often better in morning (cooler, less winds, less turbulent) 2. Many folks prefer not to fly after noon 1. >[!tip] Weather in the mountains is a trendline, it’s unlikely to get better once it starts to get worse 3. Mountain shadow can make valley airports dark early 3. Seasonal Considerations 1. Summer 1. [[Hot, High, and Heavy]] 2. Winter 1. Survival and options for emergency landings 2. [[Ice Hazards and Aircraft Icing]] 3. > [!youtube] Published by [[Air Safety Institute]] >  4. Wx information 1. [[Weather Brief]] 2. [[Area Forecast Discussion]] 3. Webcams^[Some for Tahoe area in [[Useful Bay Area Webcams]]] 4. Contact someone at the destination airport 5. Be wary -- mountain weather can change quickly! 1. Making assessments en route about signs of developing weather 5. Specific weather factors 1. Visibility 2. Turbulence 1. Mountain Wave 2. Venturi Effects 3. > [!quote] From [Winter Flying Tips and NORCAL Safety Updates](https://www.faasafety.gov/SPANS/event_details.aspx?eid=140282) > You can expect severe turbulence anytime winds aloft show changing airspeeds of more than 6kts per 1000ft 3. Clouds 1. [[Mountain Wave]] Signs![[Mountain Waves and Associated Clouds.jpeg]] 1. ![[Mountain Wave Clouds.jpeg]] 2. [[Kelvin–Helmholtz Cloud]]s 4. [[Thunderstorm]]s 5. Winds at peaks 1. Rule of thumb for winds >25 kts at peaks (from [[Tips on Mountain Flying]]) 2. Increased likelihood of [[Mountain Wave]] 6. Runway Condition Codes ([[RwyCC Assessment Matrix.png]] and [[Runway Conditions and Runway Condition Assessment Matrix]])^[See [[AC 91-79]] for more info] 4. External Pressures - Standard, but different solutions may be available 1. E.g. Too much weight can be resolved by taking multiple trips from high to low elevation airports, then departing as a group from the low altitude airport 2. Go/No-Go Decision and [[ADM]] 1. Factors of [[PAVE]] above, and how they relate to your [[Personal Minimums]] 2. Consider Canceling if (additional recommendations from [[Back to Basics - Tips to Mountain Flying]]) 1. [[IMC]] 2. Darkness falls before flight completed 3. Winds more than 30kts at mountain tops 4. Unsuitable airport conditions 3. Abort on takeoff roll for insufficient power ([[50-70 Rule]]) #### Chair Flying This Route 1. Preparation 1. Survival for off-airport landing 2. Value of using flight plans (and issues closing them at remote airports) > [!quote] [Search and Rescue](https://www.faa.gov/pilots/training/airman_education/topics_of_interest/search_rescue) by Rogers V. Shaw, III > If a flight plan is filed, the air traffic control system will automatically initiate a plan to locate overdue flights. When an aircraft on a VFR flight plan is overdue by 1 hour,^[Note [[AIM 6-2-4]] says 30 min overdue on a VFR flight plan as well] or by 30 minutes on a IFR flight plan, the Flight Service Station servicing the destination airport issues an INREQ (Information Request). If a flight plan was not filed, there is no designated time limit before a search is initiated, thus greatly delaying the onset of Search and Rescue. 2. Planning 1. Detailed route plan to avoid [[box canyon]]s or other dangerous locations 2. Consider emergency landing options 3. [[Chart Supplement]] 4. Check departure procedures for local obstructions and noise abatement 5. Alternative airports 6. [[FBO]] rental cars and courtesy cars on arrival 3. Runup 1. Leaning procedure for takeoff (always follow POH, generally in mountains use full power runup and lean to find peak power) 2. Gravel considerations (can get picked up and damage propeller) 4. Takeoff/Climb -- will take longer! 1. Calculations 2. Power Settings 3. [[PPL3.5 Short- and Soft-Field Takeoffs and Landings|Short Field Technique]] 4. May need to [[shuttle climb]] 5. Vx/Vy pitch attitudes in climb may be shallower 5. Enroute 1. Important to know wind direction (both from preflight and from signs while flying) 2. Updraft and Downdrafts 1. Use of autopilot 3. Flying along valleys -- choose a side, preferably updraft side, not the middle! 4. Consider looking for the next cylinder of air in a canyon where you can turn around continuously. This can be used as a safe place to circle if you are lost or need to resolve a situation.^[This was a tip given to Jack from a Swiss pilot. However, I haven't found good resources in the US to back this idea up, so take it with a grain of salt.] 5. [[Box Canyon]] 1. Never fly up a canyon that you haven't already flown down so you know there's room to turn around 2. NEVER try to out climb the terrain in ANY airplane 3. Make sure canyon is sufficiently wide given your turn radius 4. [[Box Canyon Turn]] technique 1. Uses 'lift flaps', likely 20° 6. Ridges 1. Fly at least 1000' above, and be there 3 miles before you arrive (although 2000' often results in less turbulence) 1. Consider only ever crossing a ridge while descending, to ensure you're not trying to out-climb terrain 2. If you can't see terrain beyond the pass, you're too low to pass 3. Approach crossing at 45° angles so better able to turn around, then depart at 90° angle 7. [[CFIT]] 8. Be comfortable stopping early if conditions deteriorate 9. Hazard Advisor tools 6. Descent/Traffic Pattern 1. May be irregular for surrounding terrain (see [[Kern Valley Airport]] -- helpful to check Google Maps/Earth before going) 2. May be on top of ridge (see [[Catalina Airport]]) with unique tabletop runway illusions^[[[Illusions Leading to Landing Errors]]] 3. Higher [[GS]] considerations 1. Careful not to overshoot final 2. Plan descent carefully 4. Be aware if airport doesn't allow for go arounds^[E.g. [[Monument Valley Airport]]] 7. Landing -- will feel fast! 1. Leaning procedure 2. Expect higher [[GS]] and [[TAS]], but same [[IAS]] 8. Parking and Securing 1. Be mindful of parking on slopes, can drain fuel 2. May need chocks or rope/stakes > [!todo] Todo Throughout Chair Flying > - Plan and plot a detailed route, including ridge crossing plans > - Research and store a copy of noise abatement procedures > - Research terrain around airports > - Compute takeoff and climb performance > - Determine cruise power settings and performance > - Review weather as though departing today ### Completion Standards Learner understands the unique considerations required for mountain flying. They are able to apply these considerations while planning subsequent mountain flying. ### Required Homework - [ ] Prepare for upcoming mountain flight ### Recommended Homework - [ ] Monitor the weather as the flight gets closer^[Forecasts too far out can be surprisingly inaccurate. It's good to see this in practice for a training flight, because knowing how to account for these issues will be relevant in future flights.] - [ ] Purchase [cannula](https://www.aerox.com/4110-701-conserving-cannula-cc/) to try oxygen, if desired