The pilot reported that, during approach, the automatic weather observation station at the airport in Pottsville, Pennsylvania, reported that the wind was from 170° at 12 knots.
He added there was “very massive choppy wind, including what could have been windshear, updrafts, and downdrafts.”
During the landing roll on Runway 11, a wind gust blew the Cessna 150 off the runway to the left. The pilot attempted to recover, but the plane hit a ditch, sustaining substantial damage to the fuselage and right wing.
The FAA inspector reported that a post-accident examination revealed that the rudder cable that passed along the left side of the fuselage was separated into three pieces. The rudder cable was covered in debris, which contained red fibers. The rudder cable was splayed and exhibited signatures consistent with tension overload.
The airplane’s illustrated parts catalog contained a diagram titled, “Rudder Control System Installation,” which displayed the cable along the left side of the fuselage cross over the right side of the airplane, in the tailcone section, and connect to the right side of the rudder horn, which provided right rudder authority.
The airplane’s most recent inspection was an annual, which was conducted six months before the accident. The FAA inspector interviewed the mechanic who performed theannual inspection, and the mechanic reported that, during inspections, he used manufacturer data and FAA Advisory Circular, AC 43.13-1B, “Acceptable Methods, Techniques, and Practices – Aircraft Inspection and Repair.” He further reported, multiple times, that he should probably “tighten up” his inspections.
AC 43.13-1B contained a section titled, “Cable System Inspection,” which stated the following: “Aircraft cable systems are subject to a variety of environmental conditions and deterioration. Wire or strand breakage is easy to visually recognize. Other kinds of deterioration such as wear, corrosion, and/or distortion are not easily seen; therefore, control cables should be removed periodically for a more detailed inspection.
“At each annual or 100-hour inspection, all control cables must be inspected for broken wire strands. Any cable assembly that has one broken wire strand located in a critical fatigue area must be replaced.”
It further stated: “Close inspection in these critical fatigue areas must be made by passing a cloth over the area to snag on broken wires. This will clean the cable for visual inspection, and detect broken wires if the cloth snags on the cable.”
It is likely that the red fibers found on the rudder cable were from a red cloth used to inspect the rudder cable during the annual inspection. It is also likely that, sometime during the flight or landing sequence, the right rudder cable separated, which subsequently restricted the pilot’s ability to recover from the loss of control during landing.
Probable cause: The failure of the right rudder cable and subsequent loss of directional control during landing.
NTSB Identification: GAA18CA020
This October 2017 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
This unfortunate pilot, 25 yrs old and 28 hrs in type, should have gone around.
in the 6120 form he reported high gusts and turbulence while 20 over the runway.[ gusts were 19 kts ]
One needs to have the mindset that every landing attempt is a go around. When everything goes ok, then land.
He says that the gust pushed the a/c off the runway onto the grass. At that point he’s a passenger, especially when the ditch collapsed the gear.
It looks like the cable frayed at the point where it crossed over the left cable.
The C150 and C152 does not have rudder return springs, so the cables will droop and probably rub in each other.
Flying a C150 in turbulence, the pilot needs to have both feet on the rudders and apply pressure to the cables. This greatly reduces the gust induced yaws.
I wonder if the taildragger technique of using brakes to assist in directional control would have prevented this runway excursion? The reported wind was within crosswind limits.
Sounds like another case of just going through the motions and not really putting their mind to the importance of the inspection.
Before you go “executing” the A&P … there’s more to most “stories” including this one. In this incident, the pilot has some culpability. That said, if he was a student … not much.
It’s fine to say “pass a cloth over the cable” per XXX but in many airplanes, you cannot get TO all parts of the cable. The tail cone of a C150 would be such an airplane. Unless you have a “midget” on staff, there’s no way to get at every portion of the cable. This article didn’t say just where the broken portion was but I’d be willing to guess that it wasn’t in a portion away from a swaged end or a pulley? That’s where wear begins, normally.
Beyond this, it doesn’t say that the pilot discovered that he didn’t have R rudder control authority IN FLIGHT !! So he’s OK until the exact instant the airplane touches down … I don’t think so ?? And what about pre-flight? When you move the rudder a bit side-to-side, you should feel some resistance (although on a Cessna, not much). The rudder should return to the center position, also. In the case of THIS airplane, the pilot should have discerned that the rudder had some sort of problem prior to flight.
Finally, this shows a lack of understanding between the control of the rudder and nosewheel steering on a Cessna single. The pedals move the rudder directly via cables that connect to the rudder horn. The pedals are also INDIRECTLY connected to the nose wheel through tubes which contain an internal spring. On the ground with the nose strut partially depressed by weight, when you move the rudder pedals, you are “suggesting” to the nose wheel through those springs what you want it to do. You can further “suggest” via use of differential braking. When in flight and the nose strut is fully extended, it automatically goes to the centered position via a centering cam arrangement.
Had the pilot known that he didn’t have R rudder control in flight on a blustery day, I’da gone to a runway where it was possible to land into the wind or — at least — be better aligned. Beyond that, if you knew that you had a problem, land in a flat 3-point attitude such that the nosewheel is on the ground and then push the elevator forward to put even more weight on the nosewheel and steer with the pedals. This isn’t 100% authority because of the springs but woulda been better than what happened.
In a taildragger, if you knew you didn’t have R rudder control, you wouldn’t do a wheel landing. Same thing when the third wheel is on the front of the airplane.
What this shows me is that CFI’s aren’t teaching students enough about the “systems” in their airplanes and what to do when they aren’t working right. Likely, even they don’t understand it all.
BTW: Different than a Cessna, the Piper airplanes have DIRECT steering of the nose wheel. No springs involved except for ‘assist’ springs on later airplanes. Again … something to remember. when you’re cross-controlling a Piper, you’re also moving the nose wheel.