In not having propellers, the jet-powered airplane is minus  two assets: (such as in a long descent), it is a handicap when it is necessary  to lose speed quickly, such as when entering a terminal area  or when in a landing flare. The lack of propeller drag, along  with the aerodynamically clean airframe of the jet, are new  to most pilots, and slowing the airplane down is one of the  initial problems encountered by pilots transitioning into jets. The typical piston-powered airplane had to deal with two  maximum operating speeds: Add the poor acceleration response of the jet engine, and it  becomes apparent that there are three ways in which the jet  pilot is worse off than the propeller pilot. For these reasons,  there is a marked difference between the approach qualities of  a piston-engine airplane and a jet. In a piston-engine airplane,  there is some room for error. Speed is not too critical and  a burst of power salvages an increasing sink rate. In a jet,  however, there is little room for error. If an increasing sink rate develops in a jet, the pilot must  remember two points in the proper sequence: These speed margins in the piston airplanes were never of  much concern during normal operations because the high  drag factors and relatively low cruise power settings kept  speeds well below these maximum limits. Maximum speeds in jet airplanes are expressed differently and  always define the maximum operating speed of the airplane,  which is comparable to the V$_{NE}$ of the piston airplane. These  maximum speeds in a jet airplane are referred to as: To observe both limits V$_{MO}$ and M$_{MO}$, the pilot of a jet  airplane needs both an airspeed indicator and a Machmeter,  each with appropriate red lines. In some general aviation jet  airplanes, these are combined into a single instrument that  contains a pair of concentric indicators: one for the indicated  airspeed and the other for indicated Mach number. Each is  provided with an appropriate red line.  [Figure 15-8] Salvaging an increasing sink rate on an approach in a jet  can be a very difficult maneuver. The lack of ability to  produce instant lift in the jet, along with the slow acceleration  of the engine, necessitates a “stabilized approach” to a  landing where full landing configuration, constant airspeed,  controlled rate of descent, and relatively high power settings  are maintained until over the threshold of the runway. This  allows for almost immediate response from the engine in  making minor changes in the approach speed or rate of  descent and makes it possible to initiate an immediate go- around or missed approach if necessary. It looks much like a conventional airspeed indicator but has  a “barber pole” that automatically moves so as to display the  applicable speed limit at all times. When the throttles are closed on a piston-powered airplane,  the propellers create a vast amount of drag, and airspeed is  immediately decreased or altitude lost. The effect of reducing  power to idle on the jet engine, however, produces no such  drag effect. In fact, at an idle power setting, the jet engine  still produces forward thrust. The main advantage is that the  jet pilot is no longer faced with a potential drag penalty of a  runaway propeller or a reversed propeller. A disadvantage,  however, is the “freewheeling” effect forward thrust at idle has  on the jet. While this occasionally can be used to advantage  Because of the higher available thrust and very low drag  design, the jet airplane can very easily exceed its speed  margin even in cruising flight and, in fact, in some airplanes  in a shallow climb. The handling qualities in a jet can change  drastically when the maximum operating speeds are exceeded. 15-7 •  M$_{MO}$—maximum operating speed expressed in terms  of a decimal of Mach speed (speed of sound). •  V$_{MO}$—maximum operating speed expressed in terms  of knots. 2. The airplane can be accelerated, assuming altitude  loss cannot be afforded, only by a rapid increase in  thrust, and here, the slow acceleration of the jet engine  (possibly up to 8 seconds) becomes a factor. 1.  Increased lift can be gained only by accelerating  airflow over the wings, and this can be accomplished  only by accelerating the entire airplane. • V$_{NO}$—maximum structural cruising speed, represented  on the airspeed indicator by the upper limit of the  green arc. It is, however, permissible to exceed V$_{NO}$  and operate in the caution range (yellow arc) in certain  flight conditions. • V$_{NE}$—never-exceed speed, represented by a red line  on the airspeed indicator. • It is not possible to produce increased lift instantly by  simply increasing power. • It is not possible to lower stall speed by simply  increasing power. The 10-knot margin (roughly the  difference between power-off and power-on stall  speed on a propeller-driven airplane for a given  configuration) is lost. Speed Margins Absence of Propeller Drag