I am continuing more of my personal King Air “war stories” for this month’s article.
We all know how worthwhile the wonderful King Air autofeather system is, right? What you may not realize, however, is that numerous King Airs also have an automatic unfeathering system.
This first came to light for me when we began training on King Airs that had been upgraded with the first examples of the Raisbeck Engineering Inc.’s Quiet Turbofan four-blade propellers. These first appeared on 200s in the early 1980s. A customer of mine had recently replaced his standard three-blade props with the new four-blade ones. During his recurrent flight training session, we shut down one engine to practice single-engine approach and go-around procedures at a safe altitude, more than 5,000 feet AGL. “That’s odd,” I thought, as I noticed that the feathered propeller never totally stopped rotation, even with the Condition Lever in Fuel Cutoff. I estimated that it was turning about 10-20 RPM.
Later, back on the ground, I phoned my friend and founder of Raisbeck Engineering, James Raisbeck, and asked him about what I had observed. “That’s normal,” was James’ response. “Our propeller blades have such a pronounced twist in them that to actually make them stop turning requires that the outer portion of the blade move past the position that has it exactly facing into the relative wind. In this position, more drag is created than if we simply allow minor rotation.”
“OK. That makes sense,” I thought. As I continued to come across these props that rotated in flight with a shutdown engine I discovered how little rotation is required to create sufficient prop oil pressure to bring the propeller blades back out of the feathered position. Realize that the oil that operates the propeller is the same oil that lubricates the engine but is not at the same pressure as engine oil. The engine’s oil pressure pump must merely move the oil from the oil tank to the inlet to the propeller governor. There, the pump inside the prop governor picks up the oil and boosts it to a much higher pressure, approaching 400 psi.
A common misconception is that the engine oil pressure pump will not be rotating fast enough, with a shutdown engine in flight, to supply the oil up to the prop governor. Depending on altitude and airspeed, N1 or Ng will still turn between three and 10 percent speed in a shutdown engine with a feathered propeller. It will only have zero speed if the compressor has locked up for some weird reason. That three to 10 percent rotation speed is enough to supply engine oil to and from the governor.
Here is an important step to take when dealing with an engine failure or shutdown in flight: Even though autofeather has worked perfectly and has feathered the propeller very expeditiously, go ahead and feather it manually yourself. Pull that propeller lever fully aft! Why? Two reasons: First, it reinforces the importance of that critical step when flying King Airs or other propeller-driven twins that do not have the autofeather system. Second, it prevents the propeller from unfeathering itself!
You see, as the “Engine Shutdown in Flight” cleanup checklist is completed, the pilot is directed to turn off the Autofeather switch. Doing that removes power from the Autofeather Dump Solenoid and it goes to its Normally Closed (N.C.) position, shutting off the path through which prop oil has been released back into the engine. That 10-20 RPM rotation is enough to allow the prop governor’s oil pump to start refilling the prop dome with oil, bringing the blades out of feather, toward lower pitch and lower blade angles. As soon as the blade begins to move, there is less rotational resistance so the prop starts turning faster and supplying more oil. It is a self-perpetuating event and the blade angle keeps getting smaller at an ever-increasing rate. Before we know it – wham! – the propeller is back at maximum speed!
Where did all this drag suddenly come from?
The same thing will happen if the pilot verifies the suspected dead engine by pulling its power lever back but then fails to push the lever forward again. Remember that both power levers must be well-advanced to activate the autofeather arming switches inside the power quadrant. Pulling either one back turns off autofeather to both sides.
My suggestions therefore are: (1) to continue your “Suspected Power Loss in Flight” memory items all the way to the end, including pulling the propeller lever fully into feather, and (2) leave the dead engine’s power lever either fully forward or matched with the other engine’s lever. By doing so the system will continue to be dumping prop oil even if we forget to turn the Autofeather switch off. It eliminates the “Where did that drag come from?” surprise … and that’s a good thing! Another disadvantage of retarding the dead engine’s power lever to Idle is that it will trigger the landing gear warning horn to sound and will illuminate the red lights in the gear handle. Although the horn may be silenced, the red lights will remain on. Hence, there will be no way to ensure that the gear is properly retracted.
If you fly a King Air in which the propeller totally stops rotation when feathered with a shutdown engine in flight, then your prop will not automatically unfeather itself. Nonetheless, I strongly suggest doing exactly the same procedures as I have advocated here. Why not stack the deck in your favor, especially since some day you probably will operate a model that exhibits some propeller rotation when shutdown?
LJ-2 Loses a Wheel
For a few months after I transferred from the Beech factory in Wichita to the Beechcraft West organization in California, I was based out of the facility in Fresno. One of Beechcraft West’s customers there ran a charter operation using a King Air 90 and a V35B Bonanza. The King Air was the second one ever built: LJ-2, a 1964 65-90 model, or “Straight 90.” By this time (early 1977) LJ-2 had received many upgrades and one of the more significant ones was reversing propellers, something the standard Straight 90 never had. The charter operation was quite busy and the King Air usually flew many times each week. A common charter saw her taking passengers down to KLAX to catch a flight out of that international hub.
The Great Central Valley of California is renowned for the winter presence of “Tule Fog.” Most mornings dawn with this heavy fog that can drop visibility to almost nothing. Taking off, barely able to see the runway centerline, almost always puts you into crystal clear blue skies by 1,000-2,000 feet. As the sun warms the air, usually the fog dissipates by midmorning, leaving lovely clear skies until the ground cools again after midnight.
One not-too-foggy morning, LJ-2 with its single pilot and a load of passengers taxied out for takeoff on their way to Los Angeles. A PSA (Pacific Southwest Airlines) Boeing 727 followed them out and held short of the runway as the King Air departed. “Uh, Fresno Tower, you may want to tell that King Air that his left main tire just fell off as he took off,” radioed the 727.
What the … ?! Sure enough, the axle nut had come loose, worked itself off, and allowed the wheel assembly to roll right off the axle. (This design has been changed on later models to decrease the likelihood of this from happening.) LJ-2’s pilot received the bad news, canceled the plans to go to LAX, and circled near Fresno in the clear air above the fog. If I am not mistaken, he began crossfeeding fuel from the left tanks to both engines, thinking that having it as light as possible on the side of the main gear “stub” would help in keeping it straight after touchdown. Radio calls were made to the Beechcraft West maintenance department and they, in turn, ran the situation past the Beech support experts in Wichita, seeking any good ideas.
It was decided to land on Runway 29R at KFAT and LJ-2 requested that a section of the runway be foamed – covered with fire-suppression foam, a common procedure back then – in preparation for the landing. Since Fresno has only two parallel runways, 29L and 29R, and both were in use, the tower offered to foam the parallel Taxiway C, which was of equal length to 29R, over 9,000 feet long. The pilot of LJ-2 accepted that offer.
After circling for two or three hours, with the fog now totally gone, LJ-2 made its approach to the foamed portion of Taxiway C. The pilot later told me that his plan was to touch down as far as possible to the right side of the taxiway. In doing so, there would be more available space for the airplane to veer left as the drag of the brake rotor – sans wheel and tire – dug into the concrete. Furthermore, he planned to use Maximum Reverse immediately after touchdown to slow the airplane as quickly as possible.
This proceeded as planned. However, the drag of the left gear stub was so great that the airplane began drifting left and could not be corrected by right rudder and right brake usage. So the pilot began easing the left power lever out of reverse. Just about the time the airplane began rolling straight, the left main stub found the dirt beside the taxiway causing even more left-side drag. So more positive trust was added by pushing the left power lever forward. The airplane was rolling at a very low speed and everyone was starting to breathe a sigh of relief, when the left main stub hit the concrete pad holding one of the taxiway lights. That impact ripped the gear strut out of the wheel well, the airplane collapsed onto the left wing, and the propeller bit into the dirt under significant positive trust. Obviously, the airplane suffered major damage. No one was injured so it was a successful emergency landing.
In hindsight, it is easy to suggest the following changes: First, go ahead and use runway 29R and take advantage of its width – about three times wider than Taxiway C. Foam? Forget it. It has been proven not to offer much protection anyway. Second, avoid immediate use of reverse. Reverse blanked out a lot of the airflow over the left wing, decreasing lift and causing the stub to dig into the concrete with greater force. Third, as the airplane slowed, if it could not be kept straight with right rudder and brake, then go ahead and use reverse as needed on the right side alone to keep it straight.
Would I or anyone else have thought of these techniques when faced with the problem in real time? I don’t know, but I suppose there is a good chance that we would not have the presence of mind to think it through completely. Perhaps this war story will be beneficial if it ever happens to you … which I hope it never does!
As a side note: I just looked at the FAA Registry and LJ-2 is still registered, in the state of Washington. It appears she was repaired successfully. Long may she fly!
FA-5 … RIP
I returned to the Beechcraft Training Center in 1984 to receive training and take the checkride to obtain my BE-300 type rating, the new King Air model that made its appearance that year. Back in those early days, obtaining the type rating on the 300 automatically earned you a BE-1900 type rating and vice versa. That was a nice loophole that has since been eliminated. One of the instructors had been there when I managed the training center and we had remained friends. I heard from him two interesting stories, one just funny and one rather sad. Let me relate both to you. First, the funny one.
As I have written in other articles and discussions, the choice of the letters that precede the serial numbers for various models of Beechcraft has always been a mystery. Why are V-tail Bonanzas “D” numbers? Why is “E” used for the 36 Bonanzas? Why LJ for 90s? Why B for 100s? BB for 200s? There must be someone who makes these choices and there must be reasons for the selection but I’ll be darned if I know who and what they are!
Over lunch one day, while we were undergoing the model 300 ground school before beginning the flight phase, my Beech instructor friend told me a secret. “Tom, we have finally decided why they chose FA as the letters for all 300s … because they are so Fantastically Awesome!” Actually, “Fantastically” may not have been the word he used, but his word did start with an F.
Now for the sad story. The company who bought the fifth 300, FA-5, sent their pilot to the Beechcraft Training Center to get typed. The company was moving up from a model 200 and the pilot had lots of experience in that predecessor model. The training went well. On the last day before the type-rating checkride was scheduled, my friend was giving this student a final training session. As was typical, they had flown a few miles northwest of Beech Field and were training at Hutchinson Regional Airport (KHUT).
An ILS to Runway 13 was planned and briefed, with a circle to land on Runway 4 – the runway mostly into the wind. The instructor pulled the flap power circuit breaker before the approach began and the student correctly identified that malfunction as he selected approach flaps. The proper no flap VREF speed, based on landing weight, was determined and now an extra element of challenge was added since the circle-to-land would be made without flaps.
All was going well as the threshold of Runway 4 was passed. The student failed to reduce power to idle soon enough – compared to the 200 he had been flying, the 300 is quite a floater! – so the 300 overshot the fixed distance markers and floated in ground effect.
With no warning or comment, the pilot reverted to a horrible habit pattern he had developed in flying the 200: He picked up both power levers to ease them back into the Beta range. Although this violates the POH limitation – Do Not lift the Power Levers in Flight – it is a technique that some 200 pilots have found works well when a little extra propeller drag is desired. With the propellers in an underspeed condition, resting on the Low Pitch Stops, the pilot can move the LPS to a flatter angle by pulling the power levers back and the airplane usually settles to the runway nicely.
Don’t do this! Someday one prop will respond and the other will not, or you will misjudge the altitude and “fall out of the sky” with a bang, or you’ll be so much above the proper VREF that the propellers won’t be in an underspeed condition so they will not enter Beta. Like the POH says: Do Not Lift the Power Levers in Flight!
The 300’s LPS system is very different from the 200’s. The 300 has two Low Pitch Stops, Flight and Ground. The Flight Low Pitch Stop (FLPS) is active in the flare but as soon as the power levers are lifted the Ground Low Pitch Stop (GLPS) is activated and the blade angle flattens by a huge 12-degree amount. This adds tremendous drag!
When the student lifted the power levers, the aircraft basically stopped flying and thudded onto the runway with a vengeance. As they rolled out, the instructor let the student know, in no uncertain terms, that he had just made a major boo-boo and to never, ever use that illegal technique again. Amid nervous laughter – glad the airplane was still operational! – the student said he’d learned his lesson!
A couple of additional takeoffs and another approach were made at KHUT and then they took the short flight back to Beech Field with one last approach there. Only when the props stopped turning at Beech did both pilots discover, in horror, that they now had the only 300 in existence with Q-Tip propellers. Remember those? They were popular for a while on Turbo Commanders as well as some other models. It was where each propeller tip was bent back at a 90-degree angle … somewhat like a winglet on a prop blade. The engines had sagged so much during the hard landing that all propeller blade tips had dug into the ground! Further investigation by the Beech mechanics and engineers revealed that the engine mounts and firewalls were bent and the main spar was damaged beyond economical repair.
The airplane died before it ever left the factory. Some parts and avionics were salvaged, but FA-5 was no more. May she Rest in Peace.
Please, don’t lift the power levers in the flare. Promise?
Another side note: FA-5 also shows up now in the FAA Registry. Either I was given the incorrect serial number or perhaps it was finally repaired successfully?
A Near “Disaster” in Mexico
In 1976, another instructor pilot from the Beechcraft Training Center and I were selected to crew a weekend BE-200 flight to Mazatlán. An oil company in Houston had bought a new 200 but its delivery had been delayed due to a couple of last-minute snags. Since the new airplane was not ready as promised, the King Air salesman in Texas asked the Wichita factory to supply one of their demonstrators for the trip. Although this did not happen often, it was occasionally provided to keep happy customers. Beech was good that way!
The other pilot, Ernie, and I flew from Beech Field to Houston’s William P. Hobby Airport (KHOU) to pick up our passengers – three couples, as I recall – then proceeded on this Friday afternoon to Mazatlán. The schedule had us returning to Houston Sunday afternoon. After clearing customs, fueling the plane and getting a ride to the nice beachfront hotel, Ernie and I were looking forward to a day and a half of relaxing and fun beach time.
We found that Hobie Cats – small sailing catamarans – were available for rent and we reserved one for Saturday afternoon. Being a bit paranoid about security on the Mexican beach, Ernie and I carefully placed our wallets, passports, pilot licenses, etc. into a hotel plastic laundry bag, inserted that bag into another one, tied them up so as to be as water-tight as possible, and then tied the whole thing to the boom for the Hobie’s sail. Off we went, enjoying the sun, the wind and the sailing. It was easy to keep an eye on our bag of stuff since the boom was just above head height as we sat in the canvas sling between the twin hulls.
Time passed as we sailed, watching the other boats, the bay’s shoreline, the resort hotels, drank a cerveza or two … doing the Mexican beach resort thing.
Then, panic! Where’s the bag?! Somehow our boom-secured bag wasn’t secure anymore! Ernie, much taller than I, grasped the mast and pulled himself up as far as he could to scan the sea around us … especially the wake behind us. Oh Lordy! A white something was bobbing in the waves far in the distance behind. We did a quick turn-about and headed in the direction of the white object. As we got closer we could see that it indeed was our missing bag of valuables. Whew! There were two very happy pilots when we hoisted that aboard. We’d probably still be in Mexico if the bag had never been retrieved!
I’ll talk to you next month!
If you have a question you’d like Tom to answer, please send it to Editor Kim Blonigen at firstname.lastname@example.org