Spiral Dive lesson
A spiral dive is a steep descending turn with the aircraft in an excessively nose-down attitude and with the airspeed increasing rapidly.
Objectives
- The recognition of the conditions which could lead to a spiral dive.
- The recognition of the spiral dive.
- The correct recovery action.
Why ?
- Spirals are probably responsible for more deaths than the spin.
- If you fly into cloud without the training and the instruments to fly blind, you will enter a spiral dive within 178 seconds!
- Spiral can overstress airplane and make structural damage.
Link
- Descent.
- Steep turn.
- Spin.
Review Questions
- What is happening if the airspeed is Increasing in spin?
- Give the procedure to enter a spin.
- Give the procedure to recover from a spin.
Spiral: basic theory
- A spiral occurs in a steep descending turn.
- Airspeed increasing rapidly.
- Excessively nose-down attitude.
- Aircraft speed limitations can be rapidly exceeded in a spiral dive.
Causes of spiral
- During a spin it is possible to become temporarily disoriented, so that what appears to be a spin is actually a spiral, under these conditions, always remember that the main difference between the two manoeuvres is airspeed.
- In steep turn if you let the nose down the airspeed will increase and the spiral occurs.
- If a spin entry is not completed properly aircraft will not achieve autorotation and will enter a spiral dive exemple:
- Attempting to force a spin before a stall.
- Relaxing elevators once in a spin.
- Poor spin recovery.
Spiral
- The speed is increasing rapidly.
- Altitude is lost at an increasing rate.
- The « g » force is increasing.
- * Wings are not stalled
Spin
- The airspeed is low and oscillates up and down.
- The rate of descent (height loss) is steady..
- The « g » force remain low.
- * Wings are stalled
Instrument Indications
Attitude Indicator (AI):
- Nose down.
- May be unreliable.
Heading Indicator (HI) :
- Changing heading.
- May be unreliable.
Air Speed Indicator (ASI):
- Rapidly increasing.
Alitmeter (ALT):
- Rapidly decreasing.
Vertical Speed Indactor (VSI):
- Show a rapid descent.
Turn-coordinator:
- Full scale deflection in the direction of spiral.
Spiral Recovery
- Close the throttle immediately.
- Roll the wing level (avoid rolling and pulling up at the same time).
- Ease out of dive by pulling up,
- Apply power only after the airspeed has decreased to within normal range and positive rate of climb.
- Don’t recover too abruptly, that could result in an excessive load factor, with a danger of a pilot black-out, structural damage, or a high-speed stall.
Review questions
- What are 3 indications you are in a spiral dive?
- What is the main difference between a spin and a spiral ?
- When can you add power during the recovery?
- How do you recover from a spiral dive ?
