Aviation's Rule of Thumb

Some common rules or other aircraft terms to remember

Aircraft Tips, Basic Flight Procedures, and Strategies for Light Aircraft

Every field has some "rules of thumb" that are truisms. Aviation is no different. The following are offered only as a way quick to remember how an aircraft performs or what you should think about when flying. In all cases FARs and the POH always overrules anything stated here and in no way should be substituted for any international or governmental regulation or what the manufacturer has stated to do in any given situation. These suggestions are for light aircraft.

Operational Good Practices

Airspace Utilization

Airspace at a glance diagramA lot of new efforts are underway in the industry. One is the Advanced Personal Air Transportation System. This is an attempt to take all the computer advances like heads-up displays, GPS, weather radar and other items normally installed in heavy metal and make them available to the general aviation flying community.

As a member of AOPA when you renew your membership you get a lot of useful items like this Airspace at a Glance reference card. On the backside of the card there is a table showing all the requirements needed to fly in that airspace.

While at Reno in 2000 I picked up from the FAA a "Guide to Airport Signs and Markings". This link will take you to Airport Signs and this one to the Airport Markings reference sheet. 72 and 80K respectively. The resolution is good enough to get a decent print from.

General Tower and Non-Tower Airport Procedures

Non Manned Tower Frequencies
Airport Facility Frequency Inbound Outbound Instrument
UNICOM CTAF 122.7, 122.8, 122.725, 122.975 or 123.0 Report in at least 10 miles out , entering downwind, base, and final approach to runway , leaving runway Before taxi and before entering runway Not allowed

 

Manned Tower Frequencies
Airport Type Frequency Inbound Outbound Instrument
No Tower or UNICOM Announce 122.9 10 miles out, downwind, base, final, leaving runway Before taxi, before entering runway Departing Final Approach Fix (FAF)
Tower not in Operation Published CATF Frequency 10 miles out, entering downwind, base, final, leaving runway Before taxi, before entering runway Approach complete or terminated
FSS Closed (no tower) Announce on CATF 10 miles out, entering downwind, base, final, leaving runway Before taxi, before entering runway N/A
Tower (FSS not in service) Announce on CATF 10 miles out, entering downwind, base, final, leaving runway Before taxi, before entering runway N/A

 

Aircraft V Speeds

 V-Speed  Definition Airspeed Indicator Marking
VSO Stall speed, flaps down, power off bottom of white arc
VS Stall speed, flaps up, power off bottom of green arc
VX Best angle-of-climb speed none
VY Best rate-of-climb speed none
VFE Maximum flaps-extended speed Top of white arc
VA Maneuvering speed none
VNO Maximum Structural cruise speed Upper limit of green arc
VNE Never-exceed speed Top of Red line
VYSE Best Single Engine Speed Rate of climb (twins)) Blue line

VMC

Minimum Controllable Airspeed Bottom of green Line

Quick Decent Calculation

To find the distance from the airport that you should start a descent subtract the pattern altitude (MSL) from your current altitude, delete the three 0s (dividing by 1000) then multiple by 3 to give you the distance you should start you descent to give you a nice steady 500 fpm decent.

Current Altitude: 6500, pattern 1500'. 6500-1500/1000*3 = 15 miles out.

Standard Day

29.92 inches of Hg at 59 F is what is used as a standard day to measure from for aircraft performance purposes.

Aircraft Checklists

Each aircraft has their own checklist created by the manufacturer and approved by the FAA. (Older aircraft may only have a Pilot Operating Handbook and no approved checklist, generally a/c made between 1890 and the 1950s when the CAA - Civil Aeronautic Authority was in existence.)

Memory Aids

RECIT - before flight

CIGAR - for takeoff

WUFTDM - after takeoff

GUMP - for landing

GUMPSS - for landing

The mixture is important since that's usually what we forget in the descent to a landing. [Thanks to Don Leonard for this.]

FAST — In Flight Piston Restart

ICE-T

Rule of Thumb for True Airspeed

Increase IAS by 2% per 1000 density feet above sea level. 5000 density altitude yields 5*2% or 10% above indicated airspeed. So 100 IAS = ~110 mph TAS at 5,000 foot density altitude.

Extra Checklist Items?

Some common things that anyone should know about their a/c but I have not seen in any checklist are:

Pre-Departure Checklist

Approach Briefing

  1. ID Procedure
  2. Final approach nav aid tuned and ID'd
  3. Inbound course verified & set in #1 CDI/HSI
  4. Final approach fix ALT ______
  5. GS crossing ALT _____
  6. Missed-approach point marked
  7. DA is at what ALT ________ and minimal visibility is _______ distance
  8. Time for approach is ______
  9. Missed approach procedure is ___________
  10. No Flags
  11. Passengers secured
  12. Flaps
  13. Power
  14. Gear

Missed Approach

  1. Pitch-up
  2. Power-up
  3. Flaps Initial
  4. Positive Rate of climb
  5. Gear Up
  6. Turn to missed course
  7. Flaps up
  8. Advise tower of missed approach

Emergency Landing

  1. Establish Best Glide speed
  2. Find a place to land (within gliding distance!)
  3. Fly directly to the landing area
  4. Try restart of engine
  5. Communicate situation (121.5 MHz, 243 MHz, 406 MHz, Activate ELT, FAA, other a/c)
  6. Once at field descend to landing altitude for field (wet, short field, long field, trees, lake)
  7. Square pattern to land into the wind (if possible)
  8. Electrical off
  9. Get out of plane, eat the candy bar crushed in you shirt and wait
  10. Start filling out paperwork

FARs

FAR Numbers only valid as of November of 2003. Always subject to change by the FAA.

Twin Engine Advice

Engine Failure advice

  1. Fly the Aircraft
  2. -->Apply rudder and aileron deflection into the good engine
  3. Mixture RICH
  4. Props High RPM
  5. Throttles FULL
  6. Flaps UP
  7. Gear UP
  8. Identify the dead engine (dead foot usually = dead engine)
  9. Raise wing on dead engine a few degrees
  10. Verify the dead engine
  11. Trim Rudder
  12. Feather dead engine

Low Altitude

  1. Throttle idle
  2. Prop Feather
  3. Mixture cutoff
  4. Check for fire
  5. Feather
  6. Squawk the IFF
  7. Talk

Low altitude is always more dangerous due to lack of time and or obstructions. Most twins have either a slight (50' per minute) or negative climb rate with one engine out. High power low and slow with one engine dead or producing minimum power is a classic way to induce a accelerated stall that turns into a spin that is nearly (99% of the time) impossible to recover from below 1500' AGL.

"If One engine quits the other will surely take you to the scene of the accident." — Old saying about engine failure on twins at low altitude.

Rated HP, Effective HP and fuel consumption

Rated HP = Maximum RPM at Full Throttle

Fuel consumption = max hp * %current power * .435 BSFC / 6 lbs (fuel weight)

Control Harmony

The term applied by pilots when the amount of force to move any one of the three directional controls each only requires the same amount of force to deflect the control surface the same amount for each.

Operating an Engine "Over Squared"

Back during the 1930s and 40s when Radial Engines predominated pilots were taught never to run an engine "over square." This was defined by dividing the RPM/100 and comparing it to the manifold pressure. i.e.: 2500 RPM and 25 Inches of Manifold pressure was fine but not to run it 2500 RPM at 30 inches of pressure. This was taught during the 1930s to prevent excessive wear on the engines due to bearings and other metals used in the engines would wear out faster at the higher engine operating range. By teaching pilots not to run "over square" the engines would last longer.

The advent of WW-II and the increase in engine ability and reliability (P-51 Mustangs with the Merlin engine would run at 52 inches of manifold pressure at 2600 RPM) changed a lot of "engine rule of thumbs." So this "over square" rule no longer applies to most aircraft engines.

As a general rule, following it will still work on most any aircraft engine to ensure low engine wear. Consult the POH section concerning the engine to find out what the best RPM/Manifold combination is for any given flight realm.

Flight Reporting

When To Give Position Reports

Under IFR


1. Leaving an assigned altitude
2. There’s a change of altitude
while VFR-on-top
3. You’re unable to climb or
descend 500 fpm
4. There’s a true airspeed change in excess of 5% or 10 knots
5. Reaching a holding fix
6. Leaving a holding fix
7. There’s a missed approach
8. There’s any kind of
equipment failure
9. Anything affects the safety
of the flight

When not in radar contact


1. Leaving a final approach
fix inbound
2. Unforecast weather
3. Change in the ETA greater than plus or minus three minutes
4. Designated reporting points

What to report at designated reporting points


1. Identification
2. Position
3. Time
4. Altitude
5. Type of flight plan
6. Name of the next reporting
point and ETA
7. Name of the next succeeding reporting point
8. Any pertinent remarks

Night Vision

Your eyes need more O2 at night. Flying above 5,000 MSL people should use O2 to improve vision. Vitamin A helps improve peripheral vision also.

Painting Propeller Tips

Painting them improves visibility of the tips which can exceed the speed of sound when turning, but you must follow some FAA rules before doing so. AC 91-42D was to owners to maintain existing paint schemes while FAA-AM-78-29 deals with how some painting may cause pilot problems due when looking at or from peripheral vision in twins.

When at an FBO it is best to point the a/c away from the office to avoid people walking into tips to and from the loading area; but then the FBO may get mad at you when you power up and all their paper in their office goes flying.

Jargon

Every profession has their own unique jargon - shorthand phrases - to convey precise information. In the aircraft world there is an official phrase book that air traffic controllers must use and there is also common phrases that is good to know.

Frequency talk

Call Signs

Thanks to Cade (x ACA) who sent me 5 more call signs for airlines.

Aircraft Types

Turbulence Strategies

Check aircraft for wrinkles afterwards.

Icing Strategies

Aeronautical Formulas

Diskloading DL = Thrust / Diameter(2) / (Pi/4)

Power = Thurst / 550 * SQRT (DL / 2p) (p = density of air 0.0023 at sea level, all other items in pounds)

Drag = .0012 * V(2) x A * Cd
(A = Wing area, Cd is Drag coefficient, V= Velocity)

V = 550 * Power / Drag

 

Disclaimer

The advice on here cannot be construed as absolute truth when it comes to operational practices when flying an aircraft in the United States, or anywhere else for that matter.

The POH (Pilot Operating Handbook) is the first place to check on how to fly an aircraft and that is always trumped by the FAA (or the people with the power in the country you are over flying) as to how the POH is interpreted in actual use. Also consult the AIM (Airman Information Manual), the PIM (Pilot Information Manual), FAA regulations as published, or other official rules for your own country and those that you fly over if you are in doubt. The FAA has the final say on safe practices on operating any aircraft in the United States.

The math functions and other information here is presented and published as is and is accurate and correct to the best of my knowledge.

Please e-mail me with any corrections.