Recovery from a Steep-banked Spiral Dive
At times, weight-shift control pilots find themselves in an unintentional steep-banked descending spiral turn. This may happen while performing an emergency descent but more commonly happens when the pilot spots something on the ground and wants to get a closer look. The pilot initiates a turn which steepens to 45 to 60 degrees of bank or greater. Through turbulence, wind gusts, or inattention the turn may develop into a steep-banked spiraling descent. If the pilot attempts to arrest the descent by pushing out the control bar and increasing pitch, the rate of turn and rate of descent will increase and an accelerated stall may ensue. It may require significant force to level the wing at this point and with some wings it may actually be impossible unless the correct technique is followed. If the maneuver began at low altitude, there will be very little time to correct the situation before a crash occurs. The appropriate recovery technique is to simultaneously reduce throttle, pull the control bar in to reduce pitch, and move the control bar to the side to level the wing. Pulling the control bar in to reduce pitch may seem contrary to a pilot’s instinct when the ground is rushing up, but it must be done to unload the wing and reduce control forces sufficiently to allow the pilot to level the wing. Once the wings are leveled, the pilot should be careful not to stall the wing or build up excessive speed to accomplish a successful dive recovery.
Practicing recovery from a steep spiral should only be performed after receiving instruction from an experienced and properly certificated flight instructor. The purpose of practicing this maneuver is to build recognition of and a reflexive response to a steep-banked spiraling dive. Start all practice at an altitude that will permit a recovery at no lower than 1,000 feet above the ground. An altitude of at least 2,500 AGL is recommended. Before starting the maneuver, the pilot should ensure that the area is clear of other traffic. Begin with a steep turn in level flight with adequate power to maintain altitude and at a speed well above the stall speed for the planned bank angle. The bank angle should be at least 45 degrees and below the manufacturer’s maximum bank limitation. Allow the aircraft to begin a slow descent with a slight reduction in power, but be careful not to exceed the manufacturer’s airspeed limitations. It may be necessary to push the control bar out somewhat as part of establishing the spiral and to control speed. Once the steep spiral is established the pilot may notice that the control forces required to level the wing or counter the wing’s overbanking tendency will have increased. Do not push the control bar further out as it will likely result in an accelerated stall. Recovery should be initiated rapidly by simultaneously reducing the throttle to idle, pulling in the control bar, and reducing the bank angle to zero. A recovery must be performed by carefully controlling pitch and G-forces as the aircraft will naturally pitch up once the wings are level. As the airspeed returns to a normal cruise speed increase the throttle to maintain level flight. The pilot must be careful not to stall the aircraft or exceed airspeed limitations at all times.
The following are some errors that are commonly made during the recovery of a steep spiral:
- Failure to adequately clear the area.
- Entering the maneuver at a speed inadequate to prevent a stall at the selected bank angle.
- Allowing the airspeed to build rapidly without beginning a recovery.
- Leveling the wing without pulling the bar in and reducing throttle.
- Excessive pitch-up attitude during the recovery.
- Stalling the wing anytime during the maneuver.
- Failure to scan for other traffic before and during the maneuver.
An emergency descent is a maneuver for descending as rapidly as possible to a lower altitude or to the ground for an emergency landing. The need for this maneuver may result from an uncontrollable fire, avoidance of other aircraft, weather, or any other situation demanding an immediate and rapid descent. The objective is to descend the aircraft as quickly as possible within the structural limitations of the aircraft. Simulated emergency descents should be made in a turn to check for other air traffic below and to look around for a possible emergency landing area. A radio call announcing descent intentions may be appropriate to alert other aircraft in the area. When initiating the descent, a bank angle of approximately 45° to 60° should be established to maintain positive load factors (“G” forces) on the aircraft. Generally, the steeper the bank angle is, the quicker the descent is. But caution should be exercised with steep bank angles for extended periods because the high G forces and rotation can cause disorientation or motion sickness, which might make matters worse. The manufacturer’s bank and speed limitations should not be exceeded.
Emergency descent training should be performed as recommended by the manufacturer, including the configuration and airspeeds. The power should be reduced to idle. The pilot should never allow the aircraft’s airspeed to surpass the never-exceed speed (VNE) or go above the maximum maneuvering (VA) speed, as applicable. In the case of an engine fire, a high airspeed descent could extinguish the fire. The descent should be made at the maximum allowable bank angle and airspeed consistent with the procedure used. This provides increased loads and drag and therefore the loss of altitude as quickly as possible. The recovery from an emergency descent should be initiated at an altitude high enough to ensure a safe recovery back to level flight or a precautionary landing.
When the descent procedure is established and stabilized during training and practice, the descent should be terminated. For longer descents, alternating turn directions should be used so the pilot does not become disorientated. Prolonged practice of emergency descents should be avoided to prevent excessive cooling of the engine cylinders. [Figure 13-7]
A fire in flight demands immediate and decisive action. The pilot must be familiar with the procedures to meet this emergency as contained in the AFM/POH for the particular aircraft. For the purposes of this handbook, inflight fires are classified as: engine fires and electrical fires. If a fire extinguisher is installed on the WSC aircraft, the passenger should be briefed on its use and the pin should be connected to the extinguisher by a lanyard so it cannot be dropped into the propeller, creating a worse situation.
An inflight engine fire is usually caused by a failure that allows a flammable substance such as fuel, oil, or hydraulic fluid to come in contact with a hot surface. This may be caused by a mechanical failure of the engine itself, an engine-driven accessory, a defective induction or exhaust system, or a broken line. Engine fires may also result from maintenance errors, such as improperly installed/fastened lines and/or fittings, resulting in leaks.
Engine fires can be indicated by smoke and/or flames coming from the engine area. They can also be indicated by discoloration, bubbling, and/or melting of the engine cowling skin in cases where flames and/or smoke are not visible to the pilot. By the time a pilot becomes aware of an inflight engine fire, it usually is well developed. Unless the aircraft manufacturer directs otherwise in the AFM/POH, the first step after discovering a fire is to shut off the fuel supply to the engine (if so equipped). The ignition switch should be left on in order to use up the fuel that remains in the fuel lines and components between the fuel selector/shutoff valve and the engine (if equipped with an electric fuel pump). This procedure may starve the fire of fuel and cause the fire to die naturally. If the flames are snuffed out, no attempt should be made to restart the engine.
If the engine fire is oil-fed, the smoke is thick and black, as opposed to a fuel-fed fire which produces bright flames with less smoke.
Some light aircraft emergency checklists direct the pilot to shut off the electrical master switch. However, the pilot should consider that unless the fire is electrical in nature, or a crash landing is imminent, deactivating the electrical system prevents the use of radios for transmitting distress messages and also causes air traffic control (ATC) to lose transponder returns.
The pilot must be familiar with the aircraft’s emergency descent procedures and remember that:
- An engine fire on a WSC aircraft means the flames are going to the rear of the aircraft where minimum components are exposed. If the BPS is used, it would change the direction of the flames, possibly setting the wing and/or fuselage on fire. The flames could also burn the parachute line, creating worse problems.
- The aircraft may be structurally damaged to the point that its controllability could be lost at any moment.
- The aircraft may still be on fire and susceptible to explosion.
- The aircraft is expendable—the only thing that matters is the safety of those on board.
The initial indication of an electrical fire is usually a slight amount of smoke and the distinct odor of burning insulation, which may not be noticeable in a WSC open flight deck. Once an electrical fire is detected, the pilot should attempt to identify the faulty circuit by checking circuit breakers, instruments, avionics, and lights. If the faulty circuit cannot be readily detected and isolated, and flight conditions permit, the battery master switch should be turned off to remove the possible source of the fire. However, any materials that have been ignited may continue to burn.
If electrical power is absolutely essential for the flight, an attempt may be made to identify and isolate the faulty circuit by:
- Turning the electrical master switch off.
- Turning all individual electrical switches off.
- Turning the master switch back on.
- Selecting electrical switches that were on before the fire indication one at a time, permitting a short time lapse after each switch is turned on to check for signs of odor, smoke, or sparks.
This procedure, however, has the effect of recreating the original problem. The most prudent course of action is to land as soon as possible.
The electrical fire could expand into a larger fire in the carriage. A fire in the cabin presents the pilot with two immediate demands: attacking the fire and getting the aircraft safely on the ground as quickly as possible.