federal aviation administration the nine deadly sins presented by kvgt faasteam sign log in sheet...

Federal AviationAdministration

The NineDeadly Sins

Presented by KVGTFAASTeam

Sign Log In Sheet for Wings Credit

Stephen Ruks ATP, CFII


The Nine Deadly SinsReferencesPilots Handbook of Aeronautical Knowledge Ch. 7 & 10

Your AFM or POH

AC 00-6A Aviation Wx

AC 61-84B Role of Preflight Preparation

FAA-P-8740-2 Density Altitude Brochure

FAA Aviation NewsMay-June 2004


The Nine Deadly Sins

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What is one of the best things you can do to avoid being a sinner?

FAA Safety - FAASTeam and Wings

Enroll in the WINGS program!

http://www.faasafety.gov/



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IntroductionMisunderstandings or lack of knowledge about our atmosphere and how it affects aircraft performance is one of the leading causes of fatal aviation accidents.

This seminar will remind you of some of the things you already know and maybe show you a few things you didn’t know.



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Altitude TypesHow many altitude definitions are there?

1. Indicated altitude2.True altitude3.Absolute altitude4.Pressure altitude5.Density altitude

Read on your altimeterHeight above MSLHeight above ground levelIndicated altitude set at 29.92PA corrected for non-standard temperature and humidity



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PressureHow do we describe atmospheric pressure, what is it, and how does it affect us?

More importantly, how does it affect our airplanes?



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PressureWhat causes pressure variations?

AltitudePressure decreases approximately one inch of mercury per 1000 feet increase in altitude.

TemperatureTemperature is the biggest factor affecting density altitude.

Temperature changes ≈ 2ºC/1000ft



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Pressure Gradient

Given the same change in pressure, the rate of change of pressure is greater in cold air than in warm air.



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Effect of non-standard temperature



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Typical GA Pitot System



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Typical Altimeter



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Altimeter Setting

Standard Atmosphere:29.92 inHg or1013.25 hPa (or mb)At sea level @ 59º F (or 15º C)

One inch of mercury = 1000 feetOne hectoPascal = 100 millibars1 inHg = 33.86 hPa



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Density Altitude

How do we calculate Density Altitude?



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Density Altitude

Three important factors contribute to high density altitude

1. Altitude2. Temperature3. Humidity

Reduced air density equates todecreased performance



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Density Altitude

Warmer air will hold more water vapor than cooler air which affects engine performance more than aerodynamic performance.

With high humidity, expect longer take-off rolls and lower climb rates. Add 10% to take-off distance.



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The Nine Deadly Sins (and their unforgiveness)

1. Using sea level VSPEEDS

2. Using gross weight VSPEEDS

3. Ignoring effect on TAS4. Ignoring effects in mountainous terrain5. Ignoring effects on landing speed and distance6. Ignoring climb gradient7. Ignoring runway environment8. Using incorrect flap settings9. Combining soft-field and obstacle techniques



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Using Sea LevelVSPEEDS

Best Climb Chart

1.



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Using Sea LevelVSPEEDS

High density altitude affects take-off & landing distance

1.

Always follow manufacturer’s recommendation.



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Using Gross WeightVSPEEDS

Climb performance decreases with increase in gross weight

2.

𝑉𝑦𝑐𝑢𝑟𝑟𝑒𝑛𝑡

¿𝑉𝑦𝐺1 2√𝑊𝑐𝑢𝑟𝑟𝑒𝑛𝑡𝑊𝑔𝑟𝑜𝑠𝑠



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Ignoring Effecton TAS

3.

VyTASVx

TAS

IAS = 150PA = 8000Temp = 95ºFTAS = 180DA = 12,000



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Ignoring Effecton TAS

Turn diameters increase.

3. IAS = 150PA = 8000Temp = 95ºFTAS = 180DA = 12,000

((v² / (11.26 x Tan Φ)) x 2) / 6076

((150² / (11.26 x 0.4245)) x 2 ) / 6076 = 1.55NM

@ 180 TAS = 2.23NMTurn diameter increased by 50%

Bank angle = 23=SRT



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Ignoring Effects In Mountainous Terrain4.

TAS increase causes turn diameter to increase



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L - D ChartBank Angle Load Factor %Increase in Induced Drag

0 1 015 1.036 7.230 1.154 33.345 1.414 10060 2 300

Stall speed (VS1) increases a whopping 41%

4.



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Ignoring Effects on Landing Speed and Distance

5.

PA=4000’, 25ºC, No wind – 1200ftPA=6000’, 38ºC, 10kt Tail – 2200ftPA=6000’, 38ºC, 10kt Tail – 3400ft w/ obstacle



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Ignoring Landing Distance6.

8000’ elevation, 2500’ long, downslope, tailwind, cliff



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Ignoring Climb Gradient

Climb gradients are in Feet/Mile not Feet/Minute (as read on VSI)

Use TAS (or GS) not IAS to calculate climb gradient

6.



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Ignoring Climb Gradient6.



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Ignoring Climb Gradient6.



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Ignoring Runway Environment

A36 Takeoff

7.

OAT = 97F, Field Elev =1293’ Altimeter 29.89”Density Altitude = 4125’, Rwy 31 4000’ paved1996 A36, Turbonormalized IO 550,GTOW = 4095, CG = 86.15”

http://www.liveleak.com/view?i=a06_1188732892



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Using Incorrect Flap SettingsIn the A36 incident, use of flaps may have made the situation even worse!

Use of the recommended flap setting works just fine when operating at near sea level altitudes but with non-turbocharged engines, there comes a density altitude above which the use of takeoff flaps actually increases ground roll.

8.



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Combining Soft-Field & Obstacle Techniques

Normally flaps only used on soft field takeoff but when used for obstacle clearance, the increase in drag drastically hinders climb performance.

Always follow manufacturer’s recommendation.

9.



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Summary

Beware, better yet, be knowledgeable, of the Nine Deadly Sins of Density Altitude

Remember the effect of DA on TAS andthe TAS effect on airplane performance

Engine performance degrades with altitudeand humidity!

Always use POH or AFM recommendations



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Any Questions?



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That’s all folks!



Stephen Ruks ATP, CFII, BPPP 702.533.1978 [email protected]

Door Prize!

Remember to sign the Log-In Sheet for credit.



Remember to sign the Log-In Sheet for credit.

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