Contents:

Why Maximum Takeoff Weight
--Structural strength and performance requirements mandate required strength.
--61 knot stall speed caps allowable G.A. light aircraft weight
--Minimum climb requirements for singles is go-around in landing configuration as another gross weight cap.
--The most restrictive of stall speed or climb requirement sets gross weight.
--Structural strength has positive limit load for normal category is 3.8G at maximum weight
--Aircraft must support 2.8 pounds without deformation and another 1.4 pounds ultimate load for every extra pound added.
--Any flight overweight gives up margins of strength, climb and stall.
--Same overweight problem is far more serious in twins.

Ultimate Load Factor
Ultimate load factor is the limit load factor multiplied by 1.5 to provide an additional measure of safety. While structural damage occurs at the limit load factor, structural failure will not occur until the ultimate load factor is reached.

Beyond book flying
What does it take to make a good pilot? Is there a perfect pilot? Does it mean going by the book? Those who write the 'book' don't fly. They are Legal Beagles trying to protect asses. They know numbers and write them without feeling.

The 'book' is in the heart. Flying is not in the book; not in the checklist. The true flying 'book' is written each day on each flight. The true flying book is judgment-knowing what to do and when. More importantly, what NOT to do.

A pilot never thinks of flying as taking a chance, taking risks. The pilot is aware of his total environment. When he's not aware, he asks for help. Knowing when and where to get help is the pilot's judgment support system. A good pilot studies accidents. He learns what can go wrong. You learn from the accident experience of others two basic things.
-- There are accidents beyond the control of pilots.
--The vast majority are pilot error which is a controllable factor.

What is pilot error? It has very little to do with reflexes. Pilot error is 95% a defect in pilot judgment. The FARs and POH restrictions on performance are always there setting the margins of safety. Every so often a pilot must fly to the shoulder of those margins. This means flying to the edges of altitude and airspeed.

Just as in flying, there is more to weather than numbers; a pilot must have a sense of pattern, knowing when enough is enough. Flying, turning back, getting help are all a part of this sense of pattern.

Performance at Density Altitudes
The POH is not reliable as a source of density altitude aircraft performance. Pilots must consider all the variables with up to 50% safety margin above those of the POH. The POH was accurate only at the moment it was in pre-draft form.
As Density Altitude Increases
---Vy ias decreases as weight decreases
---As density altitude increases the Vy speed decreases
---On reaching 8000 feet your Vy speed has decreases five/eight knots
---As density altitude increases the angle of climb ias increases
---On reaching 8000 feet your ias best angle climb speed has increased four/seven knots
---The absolute ceiling for the aircraft is when these speeds meet
---From an 8000 foot airport your ias climb speed should be five/eight knots slower and POH sea level speed.
---At the wrong airspeed the aircraft most likely will be unable to climb out of ground effect.
---While the landing speeds are always the same the climb speeds are not.
---Taking off and climbing at Vx is an emergency speed in density altitude situations you need cooling.
---Maneuvering at Vy is better than climbing at Vx in density altitude situations
---True airspeed, NOT indicated airspeed determines turn radius
---At density altitudes the true airspeed will be significantly higher and require more room for making a turn
---A 30-degree bank increases drag by 50% and a 45-degree bank increases drag by 100%
---At density altitudes you run out of options of making a 180 unless you are willing to surrender altitude.
---NEVER try to make a density altitude turn at slow speed except when planning altitude loss
---Best plan is to fly over narrow spaces where density altitudes + true airspeeds require more room to turn.
---Landing at 8000 foot density altitude increases your true landing speed 5% faster than indicated.
---Gust factors for landing are added as ½ ias converted to true
---Regardless of density altitude the only constant in all normal landings is the time of flare to touchdown.
---The distance covered in the flare and ground-roll/stopping distance will be greater at density altitudes.
---Aircraft climb speed is measured in feet per minute.
---Aircraft climb gradient is measures in feet per mile. Charts are based on clime gradient.
---You must know how to use the POH chart for takeoff performance
---Consider Sporty’s Takeoff Performance Computer (Item 2091A)
---At density altitudes you are better off not to use flaps during any takeoff.
---Do not use soft-field procedures and flap settings in density altitude situations having an obstacle.

Density Altitude and You
---You will breath in and out 20,000 times today
---Sea level air is twice as heavy with oxygen as air at 18,000 feet
---Intentional deep or rapid breathing at altitude will not increase the percentage of oxygen
---Rapid and deep breathing at altitude will decrease the percentage of carbon dioxide in your blood
---Supplemental oxygen is the only option
---Vision, especially night vision is extremely sensitive to oxygen levels in the blood
---Best to use supplemental oxygen above 10,000 day time and above 6,000 at night
---We do not notice a lack of oxygen but loss of judgment is a first symptom
---At altitude a sense of doling well is a symptom of hypoxia.
---Hypoxic symptoms are faster breathing, headache, lightheadedness, dizziness, tingling, sense of warmth, sweating, tunnel vision, euphoria, so you die happy.

Revisiting Density Altitude
--Pressure altitude, temperature, relative humidity.
--POH performance charts are based only on DRY air or zero humidity.
--POH performance is based on thrust, power, and lift all of which change for the worse with density altitudes.
--POH charts and graphs figure effects of pressure, temperature but NOT humidity.
–Moist air is always lighter than dry air.
--Engine power is set by the amount of air density it uses.
--Moisture spreads the air molecules and reduces the available air to the engine.
--There are no POH figures for humidity.
--Pressure altitude is found by setting the altimeter to 29.92 in the Kollsman window.
--Temperature is found by reference to the aircraft thermometer.
--High humidity will increase the negative effect of high pressure altitude and high temperature by 10-percent.
–Humidity effects are exponential like G-forces in a bank.
–Humidity ranges from 0 = dry, to 100-percent = wet
–Relative humidity is defined as water vapor present compared to that which could be present.
–Relative humidity is given as a percentage of 100-perecent.
–Rule of Thumb effects:
0 to 50-percent humidity with low temperature and low humidity ADD 200 feet
0 to 50-percent humidity with high temperature and low humidity ADD 1000 feet
50 to 100-percemt humidity with low temperature and high humidity ADD 400 feet
50 to 100-percent humidity with high temperature and high humidity ADD 2000 feet.
--90-degrees F at 100-percent humidity add nearly 1500’ to density altitude.
--100-degrees F at 100-percent humidity add nearly 2000’ to density altitude.
--Multiply the two above numbers by the measured relative humidity percentage for the actual correction.
--Combinations of temperature, density altitude density altitude can be increased over fifty-percent by humidity.
--Safer to use humidity correction added to pressure altitude before entering into performance charts.
--An increase of density altitude over 3000-feet is possible due to high humidity

Emergency
All POH glide distances should be figured with an additional 1000' cushion to allow for pattern turns. A FAA 50 foot obstacle will increase required landing distance by 120%. In an emergency you must do in one try what it took a skilled pilot several tries to accomplish.

Wings use true airspeed not indicated airspeed to get actual climb rate. Indicated airspeed decreases with altitude while true airspeed increases with altitude. The cruise performance charts is based upon pressure altitude, leaning and gross weight. The greatest variance in POH performance figures will be in fuel consumption. Pilots are well advised to leave a 10% margin of safety from the book figures.

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