NASA Aviation Safety Report
Posted: Thu Sep 13, 2018 8:45 pm
I rec'd the NASA Aviation Safety Report in my email and read it. This publication often presents a real-life scenario which was self-reported and asks the reader to thing about "What would YOU (the reader) have done?
Here's one similar to one that I've actually had happen to myself.
Twin Throttle Technique
Duchess Instructor’s Report
Twin Throttle Technique
Duchess Instructor’s Report
■ My student and I were practicing a simulated single engine approach.… We crossed the IAF at 2,000 feet, and then I reduced the left throttle to start the simulation. My student started to practice the emergency procedure: maintain directional control and altitude, full mixture, full props, full power (right throttle), flaps up, gear up, auxiliary pumps on, identify and verify “dead foot dead engine.” He identified the dead engine [as] the left one, so we [set] zero thrust and continued the maneuver. At this time everything was all right. Then we crossed the FAF. My student tried to decrease the manifold pressure of the good engine (right one)…to descend.… Then I realized that the manifold pressure in the right [engine] did not decrease. I took the controls and I canceled the maneuver, putting back the left prop and throttle. When I tried to decrease both throttles, I saw that manifold pressure of the right engine did not decrease.
What would YOU have done?
The Reporter's Action
■ I was talking with Tower at this time.… They asked me if I wanted to take Runway 32 or circle for Runway 28. The conditions were VFR, so I canceled the approach and started to align the plane for landing on Runway 28.… My right engine was [operating] with full power due to the throttle level [being] unable to control.… I [flew] with the left…engine at idle…to maintain a safe and stable approach.
On short final when I was sure about my landing and everything was safe with usable runway, I killed both mixtures at the same time and feathered [both] of the engines.… I landed and vacated the runway in the protected area and shutdown the plane.
======
My opinion: I'm sorry the instructor took the action he did, but glad it turned out OK for him. It could have been much worse as you might imagine.
It's unlikely that adding drag devices such as gear and flaps wouldn't have brought the airplane back to a normal mode of operation by idling the good engine
Even if a Duchess had excess power in the malfunctioning engine (unlikely considering it's an underpowered airplane on it's Best day...)… a better solution in my opinion would have been to restore the simulated engine-out to normal operations, then shut down the malfunctioning engine and demonstrated to the student the proper method of landing a multi-engine airplane on one engine. That would have been a much safer method of dealing with the problem as well as turning the event into a valuable lesson.
In my own former experience, I was making a normal visual approach to Kerrville airport in my passenger's-owned Baron and the right throttle would not reduce from cruise power for the landing. (The right throttle cable had seized from old-age/lack of lubrication.)
My solution was to reduce the power on the correctly-operating left engine to manage the approach... to the point of complete idle power....and continued the landing, which was only slightly faster than usual. On rollout, I pulled the mixture of the right engine and used the left engine to vacate the runway, then called for a tug and shut down on the taxiway.
In the NASA report, I feel it was probably unwise to feather both props on dead engines while still in-flight/before landing. I feel this way because of another incident I experienced while flying a Beech 99 with a "playful" training-captain in the right seat. While in the "flare" he feathered both props. (The PT6 engines were idling but quickly restoring power was impossible.) The sudden reduction of thrust coupled with the loss of ordinary prop-disc-drag caused a huge BALLOON and there we were 15' high with runway being eaten-up at a rate much faster than normal! The airplane refused to slow down!
Fortunately it turned out OK but I had to PLANT the airplane at higher-than-normal speed and judiciously use braking to avoid skidding tires while remaining on the (now much-shorter) remaining runway..... AND, since the props were feathered, REVERSE thrust was also denied us, something normally expected on every landing.
My training captain was as wide-eyed as myself due to his foolishness.
In the mid-1980's I witnessed the local commuter airline operating the same model airplane, landing in front of our corporate hangar on Rwy 17 at AUS Mueller. While the flare was in-progress I heard both props suddenly go in to "feather". That crew blew all four tires, ruining all four wheels to stop in the remaining runway.
Althougth these particular scenarios are unlikely to occur in our Cessna 170 aircraft.... I wanted to post this thread becasue I want to remind everyone that practicing something never-before-experienced in a "last-minute-idea".... is probably a very BAD idea as well as an example of really poor judgment. It's a good idea to avoid such silliness.
Hope this is taken in the right frame of mind. Good judgment is the hallmark of good piloting and playful, last-minute ideas are generally not part of that.
Here's one similar to one that I've actually had happen to myself.
Twin Throttle Technique
Duchess Instructor’s Report
Twin Throttle Technique
Duchess Instructor’s Report
■ My student and I were practicing a simulated single engine approach.… We crossed the IAF at 2,000 feet, and then I reduced the left throttle to start the simulation. My student started to practice the emergency procedure: maintain directional control and altitude, full mixture, full props, full power (right throttle), flaps up, gear up, auxiliary pumps on, identify and verify “dead foot dead engine.” He identified the dead engine [as] the left one, so we [set] zero thrust and continued the maneuver. At this time everything was all right. Then we crossed the FAF. My student tried to decrease the manifold pressure of the good engine (right one)…to descend.… Then I realized that the manifold pressure in the right [engine] did not decrease. I took the controls and I canceled the maneuver, putting back the left prop and throttle. When I tried to decrease both throttles, I saw that manifold pressure of the right engine did not decrease.
What would YOU have done?
The Reporter's Action
■ I was talking with Tower at this time.… They asked me if I wanted to take Runway 32 or circle for Runway 28. The conditions were VFR, so I canceled the approach and started to align the plane for landing on Runway 28.… My right engine was [operating] with full power due to the throttle level [being] unable to control.… I [flew] with the left…engine at idle…to maintain a safe and stable approach.
On short final when I was sure about my landing and everything was safe with usable runway, I killed both mixtures at the same time and feathered [both] of the engines.… I landed and vacated the runway in the protected area and shutdown the plane.
======
My opinion: I'm sorry the instructor took the action he did, but glad it turned out OK for him. It could have been much worse as you might imagine.
It's unlikely that adding drag devices such as gear and flaps wouldn't have brought the airplane back to a normal mode of operation by idling the good engine
Even if a Duchess had excess power in the malfunctioning engine (unlikely considering it's an underpowered airplane on it's Best day...)… a better solution in my opinion would have been to restore the simulated engine-out to normal operations, then shut down the malfunctioning engine and demonstrated to the student the proper method of landing a multi-engine airplane on one engine. That would have been a much safer method of dealing with the problem as well as turning the event into a valuable lesson.
In my own former experience, I was making a normal visual approach to Kerrville airport in my passenger's-owned Baron and the right throttle would not reduce from cruise power for the landing. (The right throttle cable had seized from old-age/lack of lubrication.)
My solution was to reduce the power on the correctly-operating left engine to manage the approach... to the point of complete idle power....and continued the landing, which was only slightly faster than usual. On rollout, I pulled the mixture of the right engine and used the left engine to vacate the runway, then called for a tug and shut down on the taxiway.
In the NASA report, I feel it was probably unwise to feather both props on dead engines while still in-flight/before landing. I feel this way because of another incident I experienced while flying a Beech 99 with a "playful" training-captain in the right seat. While in the "flare" he feathered both props. (The PT6 engines were idling but quickly restoring power was impossible.) The sudden reduction of thrust coupled with the loss of ordinary prop-disc-drag caused a huge BALLOON and there we were 15' high with runway being eaten-up at a rate much faster than normal! The airplane refused to slow down!
Fortunately it turned out OK but I had to PLANT the airplane at higher-than-normal speed and judiciously use braking to avoid skidding tires while remaining on the (now much-shorter) remaining runway..... AND, since the props were feathered, REVERSE thrust was also denied us, something normally expected on every landing.
My training captain was as wide-eyed as myself due to his foolishness.
In the mid-1980's I witnessed the local commuter airline operating the same model airplane, landing in front of our corporate hangar on Rwy 17 at AUS Mueller. While the flare was in-progress I heard both props suddenly go in to "feather". That crew blew all four tires, ruining all four wheels to stop in the remaining runway.
Althougth these particular scenarios are unlikely to occur in our Cessna 170 aircraft.... I wanted to post this thread becasue I want to remind everyone that practicing something never-before-experienced in a "last-minute-idea".... is probably a very BAD idea as well as an example of really poor judgment. It's a good idea to avoid such silliness.
Hope this is taken in the right frame of mind. Good judgment is the hallmark of good piloting and playful, last-minute ideas are generally not part of that.