Page 24 - Volume 15 Number 6

Three things should prevent the propeller speed from ever reaching the PPG’s speed setting when Max Reverse is selected: (1) The pilot remembers to push the propeller levers fully forward, setting the PPG at its highest setting of 2,000 RPM. It is obviously harder to reach 2,000 RPM than anything lower. The “Reverse Not Ready” annunciator mentioned above exists to remind us to push the propeller levers forward. (2) The mechanic – the engine and propeller installer – has done his job correctly and adjusted things so that the Ng reached in Max Reverse is only 82-88%, not the normal 100%+ when the same power levers go fully forward. And lastly, (3) The “icing on the cake,” as it were, is that even if the pilot makes a mistake and leaves the PPG set for too low of a speed and even if the mechanic had the Ng juiced up to, say, 95% in Max Reverse, the good old FTG should step in when the RPM gets within about 5% of “all hell breaking loose,” and come to the rescue by preventing fuel flow from continuing to go any higher. You would not get much reverse action, but that would surely be better than one prop instantaneously slamming from reverse thrust to positive thrust on the after-landing rollout, eh?
Let me tell you of an experience I personally had in which indeed “all hell broke loose” while using Maximum Reverse. I was asked to conduct a pre-purchase flight evaluation on an F90-1 model that was being considered by a potential buyer. I was told that this one-owner airplane had been both flown and maintained by only one pilot/mechanic from when it left the Beechcraft factory until now. “Isn’t that great?!” the prospective buyer asked. My reply? “Well, it may be. But also recall the adage ‘familiarity breeds contempt.’ There can be advantages of having a second or third set of eyes and hands involved at some point.”
Overall, the airplane checked out well. The paperwork was thorough and the systems worked correctly. The engines met power specifications and the pressurization worked as it should. While doing a flight evaluation, I always use maximum reverse on the landing to see if both engines come up to proper specifications. As I rapidly moved both power levers to the max reverse position after touchdown, my first thought was “Wow! This is really putting out the stopping power!” But then, the force that had been pushing me against the shoulder straps suddenly turned into a massive push and I was now slammed against the seatback. I have never flown an airplane with JATO – Jet Assisted Takeoff – but I imagine it would have felt similar. All of that reverse thrust instantaneously became forward thrust. I thank my lucky stars that both engines did the same thing. Had one remained in reverse and this had happened on only the other side, I am quite certain we would have experienced an excursion onto the grass.
Somehow this pilot/mechanic had misadjusted the Beta/Reverse rigging such that not only was too much increase in Ng being experienced but also the Fuel
22 • KING AIR MAGAZINE
MAY 2021