Electrical System
The loss of electrical power can deprive the pilot of communications and navigation systems, but for day/VFR conditions this is not a life threatening situation because most engines ignition systems are on a separate electrical system and not dependent on the battery for keeping the engine running. However, losing communications does present some challenges especially if operating at a controlled tower airport in which procedures in the Airman’s Information Manual (AIM) would be followed.
Pitot-Static System
The source of the pressure for operating the airspeed indicator, the vertical speed indicator, and the altimeter is the pitot-static system. Most WSC aircraft have pressure for the airspeed indicator. If this becomes plugged, the airspeed indicator may not read properly. If it is suspected that the airspeed indicator is not reading properly, use the feel of the aircraft and the trim position to determine speed. It is perfectly safe to fly a WSC aircraft without an airspeed indicator if the pilot has developed a feel of the aircraft since the trim position speed is known and all other speeds can be determined based on the feel of the air and the pressure on the control bar.
Altitude and vertical speed utilize static pressure. Because there is typically no static line connecting these, they operate independently. Therefore, if one fails or becomes plugged, the other can act as a reference. For example, if the altimeter fails for any reason, the vertical speed indicator would provide the pilot with information on whether the aircraft was climbing, level, or descending. The global positioning system (GPS) (if equipped) could also provide altitude readings. If the vertical speed indicator failed, the altimeter could provide information on whether the aircraft was climbing, level, or descending by looking at the altitude reading over time.
Landing Gear Malfunction
If there is any landing gear malfunction before or during takeoff, the flight or takeoff should be aborted and the malfunction fixed before attempting another takeoff. However, if a malfunction takes place during or after takeoff in which the landing gear is not completely functional for landing, the situation should be evaluated using aeronautical decision-making (ADM) to make the best choice based on the outcome of the situation.
If a tire falls off, a known flat of the tire is evident, or a landing gear strut has shaken loose or become damaged, precautionary measures must be taken to minimize the results from landing with a defective landing gear.
Fly to a smooth runway where the WSC aircraft can skid and not stop abruptly and tumble. Inform the local ATC, UNICOM, or multicom frequency that there is a MAYDAY in order to obtain immediate help for a crash landing. There is no hurry to land, so use ADM to survey the situation and make the best decision on where and how to land. Find a location that has medical support, a smooth runway that minimizes abrupt stops/tumbling, and land into the wind for the best outcome. Attempt to make a normal approach into the wind with the lowest possible speed to touchdown.
Inadvertant Propeller Strike
A propeller strike in a pusher WSC aircraft is more dangerous than in any other aircraft. If an object or the propeller is flung up into the wing trailing edge, a structural failure could occur. This situation should not be underestimated or ignored. Procedures should be implemented and followed to avoid propeller strikes from articles flying out of the flight deck. Passengers sitting in the back are the greatest risk to propeller strikes. A comprehensive preflight brief with proper flight deck management procedures should reveal any open pockets or items that could dislodge and fly into the propeller. The passenger in the back should be instructed not to take off gloves, helmet, or glasses, or pull out a camera/mobile phone without a lanyard. However, the passenger in the rear seat cannot be monitored completely; it is possible that items could fly out of the flight deck and go through the propeller, presenting a serious situation.
If a bird strike occurs or anything else hits the propeller, reduce throttle immediately and evaluate the situation. The severity of the vibration is the key element to determining what to do. If the vibration is severe, shut off the engine and make an emergency landing. Minor vibration can be tolerated, but the risk of flying with a damaged propeller, which could dislodge and hit the sail, should be minimized. It is best to shut down the engine and perform an emergency landing.
Stuck or Runaway Throttle
Throttles can stick above idle or unexpectedly increase, which is called a runaway throttle. If on the ground, a runaway throttle can be disastrous if not anticipated and mitigated. A pilot (and instructor, if teaching) should always have access to the ignition system in order to shut it off immediately in the event of a throttle stuck above idle or a runaway throttle. A runaway throttle can be caused by the pilot or student pushing on the throttle pedal during taxi or startup, thinking it is the right brake, as in an airplane. Setting the cruise throttle to full open rather than full closed during startup also causes a runaway throttle. On startup, the checklists must be followed, including cruise throttle closed, foot off of foot throttle, brake on, propeller cleared, etc. The PIC must have control of the ignition to shut it off immediately during startup and taxi. A runaway or stuck throttle during flight can be handled by climbing or flying to a suitable location where the engine can be shut off and a safe engine-off landing can be made.
Abnormal Engine Instrument Indications
The AFM/POH for the specific aircraft contains information that should be followed in the event of any abnormal engine instrument indications. The table in Figure 13-8 offers generic information on some of the more commonly experienced inflight abnormal engine instrument indications, their possible causes, and corrective actions.
It is important to know that when an engine temperature probe fails, it usually reads an unusually low value, zero, or does not register. This should be taken into account when evaluating the situation with engine instruments.