Narrative:

Partial power loss on departure - aircraft X I operated/flew .7 hours in aircraft X; a PA28-180. The plane had not flown much and had not been operated for days; per the owner. The current owner had purchased the plane and had at one time flown it frequently including cross country trips. Recently he had stopped flying it and I believe he was not a current pilot at the time we met him.[the airport] is a tower controlled. The area around the airport is a combination of commercial and residential structures. The far end of runway; has a chain link fence separating the runway from a roadway and a small dirt lot; followed on departure westbound by commercial and residential buildings. There are no available locations for emergency landing other than interstate as a possibility to the southwest and a golf course located a half mile north of the airport but at about mid-field.I was at [the] airport with a friend who was interested in purchasing the aircraft from the current owner. I have around 1000 hours of flight time as pilot in command (PIC) in PA28 models; and my friend had asked me to accompany him for the purchase evaluation. A pre-purchase inspection; which did not include a test flight; had been conducted earlier in the week by a certified a&P ia; and we had flown to look at the airplane in person and if deemed acceptable to fly the airplane and complete the purchase.we met the owner and performed a pre-flight inspection with the owner. Fuel levels in each tank were below the fuel tank 'tabs.' the tabs indicate approximately 16-17 gallons in each tank. After completing the pre-flight and briefing our plan for the evaluation flight; the owner taxied the airplane to the fuel pump and I added 9 additional gallons of 100LL to the left wing fuel tank. I visually verified the amount of fuel and took the left seat in the airplane. The owner took the right seat and my purchasing friend sat in the back seat. During the initial startup and subsequent startups; I noted that the electric fuel pump was operating and making normal operation sound.the engine started normally and idled and ran smoothly at all speeds. On run-up; magneto checks resulted in normal drops and smooth operation; with no indication of magneto problems or spark plug fouling. Carb heat operation was normal and static RPM was observed at about 2200 RPM; which seemed a bit lower than usual but not exceptionally so; as I have seen similar aircraft with static RPM speeds in runup anywhere from 2200 to 2350 RPM.after safety checks and runs; we configured the aircraft for takeoff (fuel selector on left tank and electric fuel pump was on) took [the] runway for departure. The aircraft accelerated normally and lifted off the ground normally and as expected. The winds were from the right (north) at a few knots. After passing the far end of the runway and at approximately 400 feet AGL; I noticed a slight stumble or power reduction in the engine; and then the power returned to normal. The total RPM loss was probably approximately 100 RPM and could be felt and heard. The total time of reduced power was around a half second followed by another small drop of less than 1 second before returning to normal. We continued and flew a right hand pattern; and landed normally. We taxied back to [the] runway and prepared the airplane for a second departure. I checked the mags briefly before entering the runway. Upon departure roll; as the aircraft passed through about 55mph; I felt and observed a significant drop in engine power. I immediately notified the tower I was aborting the takeoff; pulled power and applied aft elevator control to slow the airplane on the runway. We exited the runway at taxiway F and I taxied the airplane to parking.I told the owner what had happened and why I had aborted. He told me that on the first departure he had not noticed any power loss or engine change. My friend in the back seat said he can definitely noticed the power drop on both the first departure and the second aborted departure. We removed the cowling and looked for anything unusual; but did not note any anomalies visually. We discussed the situation with the mechanic at the shop on the field; where the airplane has been maintained by that mechanic. We decided to again drain fuel at the three sump fittings to validate there was no water or debris visible (there was not). We then decided to take the aircraft to the sunup area and perform several full-power extended static runs to evaluate the engine running. We decided that after the runs; we would determine if we would ask the tower for permission to conduct high speed taxis on the runway.we conducted several full-throttle run-ups of the airplane; and observed no loss of power or engine hesitation. The static RPM was around 2200. I noted that the fuel pressure would vary somewhat between middle of the range (6) and lower; closer to zero (the but still a positive value; approximately 1-2 on the non-labelled portion of the scale). I verified magneto checks were normal; that the fuel selector was set correctly for the left tank (note that this aircraft is na for the recent fuel selector placard ad). We operated with the electric fuel pump on and off; with no significant change in pressure reading. I again checked carb heat and verified it was correctly operating and leaned the engine to stumble to verify mixture controls were operating correctly. I applied carb heat and successfully leaned the engine with carb heat applied to verify power increased with leaning. We reconfigured the airplane for runway operation and requested high speed taxis from the tower.we conducted four high speed taxis; with no noticeable reduction of power during each pass. On two of the high speed taxis; I asked the owner to use his phone to record video of the tachometer and fuel pressure gauges so we could look at them if needed. After completing the four high speed taxis; we again returned to the ramp and parked. I decided that given the lack of issue on the multiple runs and four high speed taxis; I was willing to fly the airplane in the pattern; but I preferred to do so alone. I verified sufficient fuel was in both tanks visually and taxied for another set of run-ups. The run-ups were again normal and I requested a departure from [the] runway. The winds were now out of the southwest at about 6-8 its (close to straight down the runway). Upon the first departure; the plane climbed quickly and under full power. I carefully watched the tachometer and listened to the engine. At about 500 ft AGL I detected a very slight and momentary reduction of RPM; approximately 50-100; and a return to full power. I landed the airplane and taxied back to [the] runway for another departure. Upon departure; the aircraft left the ground quickly with the headwind and light load. I climbed to about 150 feet and the aircraft suddenly lost partial power. At this point the aircraft was somewhere close to mid-field over the runway. My initial determination was that if power did not return the aircraft would have no option but to land off airport; but that there would not be many options given the low altitude and buildings all around. I checked airspeed was safe and lowered the nose to maintain airspeed I saw a commercial building area straight ahead; across the street from the end of the runway; and determined I would have to point the airplane in that direction. For a moment I has resigned to a forced landing or crash. However; my though them immediately changed to recognize that if I had to crash I should do so on the airport if possible to limit damage and injury to others. I immediately cut the throttle and pulled on carb heat; quickly pulled full flaps on the manual flap bar; and pushed the nose down. The aircraft was slow enough and the configuration allowed it to descend to the runway quicker than I anticipated; probably due to the headwind. It quickly became apparent that I should be able to at least tough down on the runway; although I was not sure if I could do so in time to avoid running through the fence at the end of the runway. I slipped the airplane and flared; landed the airplane quite long and applied the brakes. I called abort on the radio and I was able to get the aircraft to slow and stop just before the end of runway pavement. I taxied off the runway; and called ground control and taxied to parking.upon parking I notified there owner what had happened and that in my opinion the aircraft was not airworthy and that no one should be flying the airplane until the cause of the issue had been determined; verified and addressed by a mechanic. It appeared; based on experience that day; that the engine was having problems with partial power loss of varying amounts in the departure phase of flight; with sufficient fuel in the tank each time; and each time in a slightly nose high attitude. On the ground in a level attitude the issue was not reproduced.the owner showed the two videos he had made during the high speed taxis to the mechanic. In the videos; one can see the pressure drop off each time and in one case the pressure drops abruptly to zero. The mechanic said he predicts there is a problem with the mechanical fuel pump but said he would need to troubleshoot the full fuel delivery system including pressure tests; and determine how to address. We parked the airplane in the tie downs and left the airport. We delayed the purchase and the parties agreed that they will wait until repairs have been made and the issues cause determined and verified as having been addressed. Aside from there obvious problem of the partial power loss as noted; the aircraft flew well and as expected.in hindsight; I recognize that the power degradations occurred in a nose high attitude that cannot be easily or effectively reproduced on the ground. Realizing that; it would have been a smarter decision to not conduct the final two flights in the aircraft; and that the better decision would have been to park the aircraft and require the mechanic to determine what the issue was before being willing to fly its again. The pressure of having traveled to another state for an aircraft purchase; combined with the fact that a significant expense had already been incurred through pre-purchase inspections and airline ticket and hotel costs; likely influenced my judgment in deciding to fly the airplane. Evidence of this is my desire to not carry the other two people with me on those flights; which shows I was concerned to some extent about potential risk which I did not have to take. This experience will cause me to think twice in the future about the decision process and about not allowing that sort of natural emotional influence to compromise my decision making process.

Related reports:

Google
 

Original NASA ASRS Text

Title: PA28 Pilot reported partial power loss on a pre-purchase flight check.

Narrative: Partial Power Loss on departure - Aircraft X I operated/flew .7 hours in Aircraft X; a PA28-180. The plane had not flown much and had not been operated for days; per the owner. The current owner had purchased the plane and had at one time flown it frequently including cross country trips. Recently he had stopped flying it and I believe he was not a current pilot at the time we met him.[The airport] is a tower controlled. The area around the airport is a combination of commercial and residential structures. The far end of runway; has a chain link fence separating the runway from a roadway and a small dirt lot; followed on departure westbound by commercial and residential buildings. There are no available locations for emergency landing other than Interstate as a possibility to the southwest and a golf course located a half mile north of the airport but at about mid-field.I was at [the] airport with a friend who was interested in purchasing the aircraft from the current owner. I have around 1000 hours of flight time as Pilot in Command (PIC) in PA28 models; and my friend had asked me to accompany him for the purchase evaluation. A pre-purchase inspection; which did not include a test flight; had been conducted earlier in the week by a certified A&P IA; and we had flown to look at the airplane in person and if deemed acceptable to fly the airplane and complete the purchase.We met the owner and performed a pre-flight inspection with the owner. Fuel levels in each tank were below the fuel tank 'tabs.' The tabs indicate approximately 16-17 gallons in each tank. After completing the pre-flight and briefing our plan for the evaluation flight; the owner taxied the airplane to the fuel pump and I added 9 additional gallons of 100LL to the left wing fuel tank. I visually verified the amount of fuel and took the left seat in the airplane. The owner took the right seat and my purchasing friend sat in the back seat. During the initial startup and subsequent startups; I noted that the electric fuel pump was operating and making normal operation sound.The engine started normally and idled and ran smoothly at all speeds. On run-up; magneto checks resulted in normal drops and smooth operation; with no indication of magneto problems or spark plug fouling. Carb heat operation was normal and static RPM was observed at about 2200 RPM; which seemed a bit lower than usual but not exceptionally so; as I have seen similar aircraft with static RPM speeds in runup anywhere from 2200 to 2350 RPM.After safety checks and runs; we configured the aircraft for takeoff (fuel selector on left tank and electric fuel pump was on) took [the] runway for departure. The aircraft accelerated normally and lifted off the ground normally and as expected. The winds were from the right (north) at a few knots. After passing the far end of the runway and at approximately 400 feet AGL; I noticed a slight stumble or power reduction in the engine; and then the power returned to normal. The total RPM loss was probably approximately 100 RPM and could be felt and heard. The total time of reduced power was around a half second followed by another small drop of less than 1 second before returning to normal. We continued and flew a right hand pattern; and landed normally. We taxied back to [the] runway and prepared the airplane for a second departure. I checked the mags briefly before entering the runway. Upon departure roll; as the aircraft passed through about 55mph; I felt and observed a significant drop in engine power. I immediately notified the tower I was aborting the takeoff; pulled power and applied aft elevator control to slow the airplane on the runway. We exited the runway at Taxiway F and I taxied the airplane to parking.I told the owner what had happened and why I had aborted. He told me that on the first departure he had not noticed any power loss or engine change. My friend in the back seat said he can definitely noticed the power drop on both the first departure and the second aborted departure. We removed the cowling and looked for anything unusual; but did not note any anomalies visually. We discussed the situation with the mechanic at the shop on the field; where the airplane has been maintained by that mechanic. We decided to again drain fuel at the three sump fittings to validate there was no water or debris visible (there was not). We then decided to take the aircraft to the sunup area and perform several full-power extended static runs to evaluate the engine running. We decided that after the runs; we would determine if we would ask the tower for permission to conduct high speed taxis on the runway.We conducted several full-throttle run-ups of the airplane; and observed no loss of power or engine hesitation. The static RPM was around 2200. I noted that the fuel pressure would vary somewhat between middle of the range (6) and lower; closer to zero (the but still a positive value; approximately 1-2 on the non-labelled portion of the scale). I verified magneto checks were normal; that the fuel selector was set correctly for the left tank (note that this aircraft is NA for the recent fuel selector placard AD). We operated with the electric fuel pump on and off; with no significant change in pressure reading. I again checked carb heat and verified it was correctly operating and leaned the engine to stumble to verify mixture controls were operating correctly. I applied carb heat and successfully leaned the engine with carb heat applied to verify power increased with leaning. We reconfigured the airplane for runway operation and requested high speed taxis from the tower.We conducted four high speed taxis; with no noticeable reduction of power during each pass. On two of the high speed taxis; I asked the owner to use his phone to record video of the tachometer and fuel pressure gauges so we could look at them if needed. After completing the four high speed taxis; we again returned to the ramp and parked. I decided that given the lack of issue on the multiple runs and four high speed taxis; I was willing to fly the airplane in the pattern; but I preferred to do so alone. I verified sufficient fuel was in both tanks visually and taxied for another set of run-ups. The run-ups were again normal and I requested a departure from [the] runway. The winds were now out of the southwest at about 6-8 its (close to straight down the runway). Upon the first departure; the plane climbed quickly and under full power. I carefully watched the tachometer and listened to the engine. At about 500 ft AGL I detected a very slight and momentary reduction of RPM; approximately 50-100; and a return to full power. I landed the airplane and taxied back to [the] runway for another departure. Upon departure; the aircraft left the ground quickly with the headwind and light load. I climbed to about 150 feet and the aircraft suddenly lost partial power. At this point the aircraft was somewhere close to mid-field over the runway. My initial determination was that if power did not return the aircraft would have no option but to land off airport; but that there would not be many options given the low altitude and buildings all around. I checked airspeed was safe and lowered the nose to maintain airspeed I saw a commercial building area straight ahead; across the street from the end of the runway; and determined I would have to point the airplane in that direction. For a moment I has resigned to a forced landing or crash. However; my though them immediately changed to recognize that if I had to crash I should do so on the airport if possible to limit damage and injury to others. I immediately cut the throttle and pulled on carb heat; quickly pulled full flaps on the manual flap bar; and pushed the nose down. The aircraft was slow enough and the configuration allowed it to descend to the runway quicker than I anticipated; probably due to the headwind. It quickly became apparent that I should be able to at least tough down on the runway; although I was not sure if I could do so in time to avoid running through the fence at the end of the runway. I slipped the airplane and flared; landed the airplane quite long and applied the brakes. I called abort on the radio and I was able to get the aircraft to slow and stop just before the end of runway pavement. I taxied off the runway; and called ground control and taxied to parking.Upon parking I notified there owner what had happened and that in my opinion the aircraft was not airworthy and that no one should be flying the airplane until the cause of the issue had been determined; verified and addressed by a mechanic. It appeared; based on experience that day; that the engine was having problems with partial power loss of varying amounts in the departure phase of flight; with sufficient fuel in the tank each time; and each time in a slightly nose high attitude. On the ground in a level attitude the issue was not reproduced.The owner showed the two videos he had made during the high speed taxis to the mechanic. In the videos; one can see the pressure drop off each time and in one case the pressure drops abruptly to zero. The mechanic said he predicts there is a problem with the mechanical fuel pump but said he would need to troubleshoot the full fuel delivery system including pressure tests; and determine how to address. We parked the airplane in the tie downs and left the airport. We delayed the purchase and the parties agreed that they will wait until repairs have been made and the issues cause determined and verified as having been addressed. Aside from there obvious problem of the partial power loss as noted; the aircraft flew well and as expected.In hindsight; I recognize that the power degradations occurred in a nose high attitude that cannot be easily or effectively reproduced on the ground. Realizing that; it would have been a smarter decision to not conduct the final two flights in the aircraft; and that the better decision would have been to park the aircraft and require the mechanic to determine what the issue was before being willing to fly its again. The pressure of having traveled to another state for an aircraft purchase; combined with the fact that a significant expense had already been incurred through pre-purchase inspections and airline ticket and hotel costs; likely influenced my judgment in deciding to fly the airplane. Evidence of this is my desire to not carry the other two people with me on those flights; which shows I was concerned to some extent about potential risk which I did not have to take. This experience will cause me to think twice in the future about the decision process and about not allowing that sort of natural emotional influence to compromise my decision making process.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.