This is an excerpt from a report made to the Aviation Safety Reporting System. The narrative is written by the pilot, rather than FAA or NTSB officials. To maintain anonymity, many details, such as aircraft model or airport, are often scrubbed from the reports.
Planned flight for the day was to ZZZ1 for fuel then to ZZZ. Preflight planning conducted with assistance from ForeFlight mobile application. Departed Runway XX. Climb to 1,500 MSL, 14 minute cruise to ZZZ1 with landing. Landed at ZZZ1. The flight was conducted satisfactorily.
The Cessna 172 was then fueled as necessary. Secondary preflight planning was completed. Satisfactory takeoff and climb out to 7,500 MSL.
After approximately 29 minutes started to notice engine roughness with a significant drop in tachometer rpm.
The Pilot In Command (PIC) took over as sole manipulator of controls and emergency checklist for engine failure in flight initiated. Looked for suitable landing area. Increase in engine rpm occurred and became within glide distance of ZZZ. Engine roughness and drop in rpm began again and ZZZ Tower contacted, advising of need for precautionary landing due to engine roughness. Decision was made to not get priority handling. Smooth and satisfactory landing made at ZZZ.
After slowing and attempting to turn off runway, the aircraft did not have any right turning authority. Airplane would only turn left in circle when power applied. Suspected right tire or brake malfunction.
Contacted the Tower and asked for permission to shut down aircraft on runway to inspect aircraft. Aircraft was satisfactorily shut down on Runway XY with airport crew arriving for assistance.
On post-flight walk around, it was found that the right tire became flat, no other external damage observed. Also found to have fluid leak within right pilot side inside firewall.
Aircraft was towed to FBO for diagnostics of engine and repair of right tire. When asked if needed to report anything to Tower or FAA, the ZZZ airport crew stated nothing was needed. Furthermore, the Tower did not mention of any need to provide any post flight report during communications. No accident or serious incident occurred.
There were a few factors found on post-flight that may have caused the problems:
Engine Roughness: The engine was new with approximately 28 hours on the engine. Engine during break in period was using Aeroshell 100W. Furthermore, this flight was conducted with cruise altitude at 7,500 MSL. Miscommunication and ill-information about any special procedures regarding aircraft break in were not discussed between aircraft owner and PIC. PIC was told to use 100W oil from previous aircraft owner (box in back of aircraft). Furthermore, the aircraft owner did not provide engine overhaul information or procedures needed for aircraft.
On mechanic review, it was found that the left magneto was rotated 17°, causing the engine to overheat, an oil line by the firewall was damaged causing a leak, cylinders were glazed, induction air leak, and some crankcase oil leak.
Overall a combination of these factors is what probably lead to engine roughness.
Post-flight testing, the engine performed within specifications 2250 static rpm, 600 fpm climb, 2350 dynamic rpm.
Engine oil consumption has increased, likely due to glazed cylinders, and is being sent for re-honing.
Furthermore, the magnetos are being sent in to be re-checked.
Right Flat Tire: No noted gross evident issues on pre-flight inspection for tires, struts, fairing, or braking systems. Landings was smooth and satisfactory. Theory for tire damage could be due to stuck break after landing and prior to right turn out to taxiway, in conjunction with weak spot on tire and/or a foreign object on runway and/or other. Tire was satisfactorily repaired at ZZZ.
Reviewing this scenario there are a few factors to consider. There needs to be improved communication between aircraft owner and operator (PIC), especially during critical times where specific procedures are needed (such as a new engine break in).
The right tire flat is a chance occurrence, and I do not think that the flight could have been handled different to prevent.
The pilot did all in power to safely shut down the aircraft and immediately check out airplane to prevent any further damage.
I have a clean pilot record, commercial license and CFI. I will use the lessons from this flight for myself and all future students for the purpose of discussing complete airplane maintenance with airplane owners (especially new airplanes), what to do when engine becomes rough, and procedures to follow with a flat tire.
Primary Problem: Aircraft
ACN: 1821169
Many things to poke at (good-naturedly) in this incident, but since everything turned out “satisfactory”, and “no accident or serious incident occurred”, I’ll focus on one of my personal pet peeves:
“Experienced engine roughness with a significant drop in tachometer RPM.”
They clearly have no idea why.
“The PIC took control and ran the EMERGENCY CHECKLIST for Engine Failure in Flight.”
Great idea.
“…and looked for suitable landing area.”
Very prudent decision.
“Increased in engine RPM occurred and became within glide distance of ZZZ.”
Hallelujah! It healed itself!
“Engine roughness and drop in RPM began again.”
Oops, never mind.
“…ZZZ Tower contacted, advising of need for precautionary landing due to engine roughness. Decision was made to not [get priority handling].”
So, we are not going to declare an Emergency. We’re betting this engine is not going to quit before we get to the runway, and since we’re within “gliding distance” we don’t need “priority” over anybody else that might be trying to do the same thing, like, land. Sure hope we don’t have to execute a go-around d/t traffic conflicts, insufficient spacing, another student pilot blowing a tire at touchdown, airport ops truck on the runway, etc., with our sick engine.
“Smooth and satisfactory landing made at ZZZ.”
Thank goodness, we didn’t have to highlight ourselves by saying the “E-word” on the radio!
“After slowing and attempting to turn off Runway, the aircraft did not have any right turning authority. Airplane would only turn left in circle when power applied.”
Rutroh! I hate it when that happens. Must be a former NASCAR pace plane.
“Suspected right tire or brake malfunction.”
That is a logic leap I would not have been able to make.
“Contacted Tower and asked for permission to shut down aircraft on runway to inspect aircraft. Aircraft was satisfactorily shut down on Runway XY with airport crew arriving for assistance.”
Well, if you can’t get off the runway, their options are pretty limited. So, you basically end up doing the same thing that would have happened if an Emergency had been declared; only, in this case, they had no time to get ready for your arrival.
“On post flight walk around, it was found that the right tire became flat, no other external damage grossly observed.”
Define “grossly”.
“Theory for tire damage could be due to stuck break after landing and prior to right turn out to taxiway, in conjunction with weak spot on tire and/or a foreign object on runway and/or other. Tire was satisfactorily repaired at ZZZ.”
Well, if it was repaired, wouldn’t you know what the actual damage was?
“Reviewing this scenario there are a few factors to consider.”
Absolutely. It all started with a situation that required running an Emergency Checklist and ended with the plane shutting down a runway and being towed off. I wonder if any other aircraft were affected as a result?
“I will use the lessons from this flight for myself and all future students for the purpose of discussing…. what to do when engine becomes rough, and procedures to follow with a flat tire.”
I hope that includes a very thorough discussion on when it is appropriate to declare an Emergency, especially when there’s a chance that the engine might quit, and/or you’re going to shut down a runway—assuming you make it to one. Lots of folks will correctly argue that it would not have made a difference in this scenario: What about next time?
Culprits…Phonics and new math…. 🙂
Am I reading this wrong? If the right tire was flat, it would seem to me that the plane would turn in the direction of the flat, that is, to the right, not to the left as stated.
You got it. He’s been watching too many aviation chain of blame videos.