Flight #: 9 — STABILITY AND CONTROL CHECKS

Pilot:

Date:

Time:

Objectives:

  • Determine longitudinal stability
  • Determine lateral-directional stability
  • Determine spiral stability

Check

Action

   
 

PRE-FLIGHT

 

These tests cannot be accomplished until any necessary trim tabs have been installed so the aircraft can be flown hands off

   
 

DEPARTURE

 

Do not use flaps

 

Climb out at 110 MPH

 

Climb to 6000’ MSL and level off

   
 

CRUISE

 

Limit prop RPM to 2300

 

Check engine gauges especially CHT and Oil Temp

 

Trim hands off level flight

   
   
   

NOTES

 

Check

Action

 

LONGITUDINAL STABILITY TEST

 

Record airspeed at 2300 RPM (Airspeed ___ = A)

 

Lightly pull on stick to reduce airspeed by 10%

 

New airspeed: A-10%= ___ = B

 

Does the acft. require continued pull force to maintain the new airspeed?

 

If yes: Pull stick to reduce airspeed to A-20% =___= C

 

Does acft. require still more pull force to maintain airspeed C?

 

If yes: N9X has POSITIVE static stability

 

If no to either B or C airspeed, N9X has NEUTRAL static stability

 

If N9X requires a push force for B or C airspeeds, then N9X has NEGATIVE static stability

 

---- repeat test using a PUSH test instead of PULL test

   
 

TEST FOR POSITIVE DYNAMIC LONGITUDINAL STABILITY (SHORT PERIOD)

 

Trim for cruise @ 2300 RPM

 

Push nose down 5 degrees, then up to level attitude

 

As attitude reaches level, release stick

 

If N9X briefly oscillates about the trim attitude before settling at trim attitude then N9X has POSITIVE DYNAMIC LONGITUDINAL STABILITY (SHORT PERIOD)

   
   
   

NOTES

Check

Action

 

TEST FOR POSITIVE DYNAMIC LONGITUDINAL STABILITY (LONG PERIOD)

 

Trim for cruise @ 2300 RPM, Record Airspeed ___ = A

 

Pull stick for A - 5 MPH and release stick

 

Expect N9X to oscillate about the trim speed before in dampens out

 

If amplitude INCREASES with time = NEGATIVE DLS

 

If amplitude CONTINUES to oscillate = NEUTRAL DLS

 

If N9X returns to cruise trim & speed = POSITIVE DLS

   
 

TEST FOR LATERAL/DIRECTIONAL CONTROL STABILITY

 

Set low cruise speed (BELOW MANEUVERING SPEED) & trim

 

Slowly enter a sideslip until either full rudder or full aileron deflection

 

Release aileron while holding full rudder

 

---> low wing should raise to level

   
 

TEST FOR STATIC DIRECTIONAL STABILITY

 

Set low cruise speed (BELOW MANEUVERING SPEED) & trim

 

Slowly yaw N9X with rudder while keeping acft level with aileron ----- release rudder

 

N9X should return to no yaw condition

   
   

NOTES

 

Check

Action

 

TEST SPIRAL STABILITY

 

(This will demonstrate the aircraft's tendency to raise the low wing when controls are released in a bank)

 

Bank 15 to 20 degrees and release controls

 

---> If bank angle DECREASES = POSITIVE SS

 

---> If bank angle STAYS THE SAME = NEUTRAL SS

 

---> If bank angle INCREASES = NEGATIVE SS

   
   
   
   
   
 

LANDING

 

Use checklists

 

Fly pattern at 85 MPH

 

Taxi back and "Smile"

   
 

POST FLIGHT

   
 

Prepare corrective action list

 

Record fuel and oil consumption

NOTES