skip to main |
skip to sidebar
On most modern turbocharger engines, the position of the waste gate is governed by a pressure-sensing control mechanism coupled to an actuator. Engine oil directed into or away from this actuator moves the waste gate position. On these systems, the actuator is automatically positioned to produce the desired MAP simply by changing the position of the throttle control. Other turbo charging system designs use a separate manual control to position the waste gate. With manual control, you must closely monitor the manifold pressure gauge to determine when the desired MAP has been achieved. Manual systems are often found on aircraft that have been modified with after market turbo charging systems. These systems require special operating considerations. For example, if the waste gate is left closed after descending from a high altitude, it is possible to produce a manifold pressure that exceeds the engine's limitations. This condition is referred to as an over boost, and it may produce severe detonation because of the leaning effect resulting from increased air density during descent. Although an automatic waste gate system is less likely to experience an over boost condition, it can still occur. If you try to apply takeoff power while the engine oil temperature is below its normal operating range, the cold oil may not flow out of the waste gate actuator quickly enough to prevent an over boost. To help prevent over boosting, you should advance the throttle cautiously to prevent exceeding the maximum manifold pressure limits. Tag: Flying instrument, instrument flight, aviation, piloting, instrument rating, instrument flying training, instrument flight rating, instrument rating requirement, instrument rating regulation, aircraft, aeronautic, airplane, and aeronautical knowledge. There are system limitations that you should be aware of when flying an aircraft with a turbocharger. For instance, a turbocharger turbine and impeller can operate at rotational speeds in excess of 80,000 r.p.m. while at extremely high temperatures. To achieve high rotational speed, the bearings within the system must be constantly supplied with engine oil to reduce the frictional forces and high temperature. To obtain adequate lubrication, the oil temperature should be in the normal operating range before high throttle settings are applied. In addition, you should allow the turbocharger to cool and the turbine to slow down before shutting the engine down. Otherwise, the oil remaining in the bearing housing will boil, causing hard carbon deposits to form on the bearings and shaft. These deposits rapidly deteriorate the turbocharger's efficiency and service life. For further limitations, refer to the AFM/POH.
You can expect to make many of the following common scanning errors, both during training and at any subsequent time, if you fail to maintain basic instrument proficiency through practice: - Fixation, or staring at a single instrument, usually occurs for a good reason, but has poor results. For instance, you may find yourself staring at your altimeter, which reads 200 feet below the assigned altitude, wondering how the needle got there. While you gaze at the instrument, perhaps with increasing tension on the controls, a heading change occurs unnoticed, and more errors accumulate. Another common fixation is likely when you initiate an attitude change. For example, you establish a shallow bank for a 90° turn and stare at the heading indicator throughout the turn, instead of maintaining your cross-check of other pertinent instruments. You know the aircraft is turning and you do not need to recheck the heading indicator for approximately 25 seconds after turn entry, yet you cannot take your eyes off the instrument. The problem here may not be entirely due to cross-check error. It may be related to difficulties with one or both of the other fundamental skills. You may be fixating because of uncertainty about reading the heading indicator (interpretation), or because of inconsistency in rolling out of turns (control).
- Omission of an instrument from your cross-check is another likely fault. It may be caused by failure to anticipate significant instrument indications following attitude changes. For example, on your roll-out from a 180° steep turn, you establish straight-and-level flight with reference to the attitude indicator alone, neglecting to check the heading indicator for constant heading information. Because of precession error, the attitude indicator will temporarily show a slight error, correctable by quick reference to the other flight instruments.
- Emphasis on a single instrument, instead of on the combination of instruments necessary for attitude information, is an understandable fault during the initial stages of training. You naturally tend to rely on the instrument that you understand most readily, even when it provides erroneous or inadequate information. Reliance on a single instrument is poor technique. For example, you can maintain reasonably close altitude control with the attitude indicator, but you cannot hold altitude with precision without including the altimeter in your crosscheck.
Tag: Flying instrument, instrument flight, aviation, piloting, instrument rating, instrument flying training, instrument flight rating, instrument rating requirement, instrument rating regulation, aircraft, aero plane, airplane, and aeronautical knowledge.
Taxiing and Takeoff - Turn coordinator—during taxi turns, check the miniature aircraft for proper turn indications. The ball should move freely. The ball should move opposite to the direction of turns. The turn instrument should indicate in the direction of the turn. While taxiing straight, the miniature aircraft should be level.
- Heading indicator—before takeoff, rechecks the heading indicator. If your magnetic compass and deviation card are accurate, the heading indicator should show the known taxiway or runway direction when the airplane is aligned with them (within 5°).
- Attitude indicator—if the horizon bar fails to remain in the horizontal position during straight taxiing, or tips in excess of 5° during taxi turns, the instrument is unreliable. Adjust the miniature aircraft with reference to the horizon bar for the particular airplane while on the ground. For some tricycle-gear airplanes, a slightly nose-low attitude on the ground will give a level flight attitude at normal cruising speed.
Tag: Flying instrument, instrument flight, aviation, piloting, instrument rating, instrument flying training, instrument flight rating, instrument rating requirement, instrument rating regulation, aircraft, aero plane, airplane, and aeronautical knowledge. Tag: Types of Airspeed, Indicated Airspeed, Calibrated Airspeed, Equivalent Airspeed, True Airspeed, Mach number, Maximum Allowable Airspeed, and Airspeed Color Code. Engine Shut Down When shutting down the engine, note any abnormal instrument indications.
