M-14P/V-530 Prop Seal Failure

Discussion in 'Safety Forum' started by AcroGimp, Apr 18, 2018.

  1. Apr 18, 2018 #1

    AcroGimp

    AcroGimp

    AcroGimp

    EAA 14, IAC 36

    Joined:
    May 8, 2012
    Messages:
    212
    Likes Received:
    43
    I was leading a 3-ship formation aerobatic flight in the Yak on Saturday, we had been out for about 45 minutes, when I noted a prop surge on the downline of a Quarter-Clover Down figure. We were about 3/4 mile offshore and about 15 miles over the ground away from our home airport.

    I reported the surge to my wingmen and called knock-it-off and turned towards the coast. I gave the lead to one of my wingmen so I could focus on flying/troubleshooting and have him navigate us under the Class B and back to our home field. I noted that CHT's were on the low end of the green arc and I know that my engine does not like to be on either end of the green arc and suspected this was my issue.

    1/3 of the way back I started to get oil on the windscreen, a light film in the beginning but quickly it went fully opaque, I told Lead I need a straight in and Tower was helpful. I was now getting a little smoke in the cockpit, clearly heated/burning oil.

    I made it to short final, gear and flaps down, rolled wings level and set it down, got off the runway and taxied back to hangar and shutdown uneventfully.

    Watching the cockpit cam, it was 11.5 minutes from the prop surge to shutdown outside my hangar. The oil on the windscreen appeared 3 minutes after the prop surge - and in 8 minutes approximately 10 of a total of 12 quarts of oil was lost overboard.

    The after action report is that while we did most things right I made a few critical errors too - we had an alternate airport available that is a pain to get in and out of (controllers are not helpful) but it would have put me on the ground fully 3 minutes earlier.

    Standard practice for formations is the distressed aircraft is lead so that the wingmen can provide support as needed, including nav or comms; had we followed this one or both wingmen would have noticed the oil on the plane and we would have figured out how substantial the leak was - I did not know how bad it was until I pulled of the runway and saw the wings.

    I was focused on the low CHT and never really focused on Oil Temp/Px, even after the oil on the windscreen. I believe this is because they were normal, through shutdown as it turns out, but I did not really focus on them.

    After I had the smoke/smell in the cockpit and I had the airport in sight I descended from 2,000' towards TPA of 1,600' - although I was still nearly 3 miles out - we don't glide well in the Yaks and I am the most vocal proponent of altitude when in the pattern - I suspect it was because I really wanted to get the plane on the ground but I gave up some of the altitude I had which equates to time/options.

    When we tore the hub open we found a 2.5" failure in the apex of the chevron seal, suspect a manufacturing defect - but there was also some fretting/gouging in the dome bore 180 degrees opposite the tear/failure that had lightly chewed into the outer edge of the seal on that side, also roughly 2.5" across - after 6 hours of operation.

    M-14P engine oil system nominal pressure is 71-85 psi - if you give the oil a path of least resistance, it is going to take it.

    We are going to swap out a spare piston and dome from his project with new seals and see how things behave - will ask vendor to warranty the seal, since the failure looked like it could have been a defect.

    Mechanic may try to mic the bore and see if it is out of round.

    Not sure what drove that contact or how it happened, could be the seal doubled up when it failed and pushed the piston offcenter on the opposite side, but it was pretty substantial - no wear noticed on the oil delivery tube that the piston rides on so kind of confused. My mechanic is going to swing by our area Russian mechanic and see if he has any thoughts/has seen anything like it.

    In hindsight, I did not feel like it was serious enough to consider declaring until the last 2-3 minutes and by that time I was on approach - my wingman who was leading informed tower that I needed to get in expeditiously, fortunately traffic was low for a Saturday and I was able to just drive in.

    I have cockpit video but my audio cable disconnected from my headmounted GoPro early in the flight so no comms, I'd be really interested in hearing that.

    Again, in hindsight, I really made a couple bad decisions at critical phases - passed up an alternate airport (before it was obvious how critical the situation was), if we had declared I could gotten a clearance through the Bravo and made a straight in on the crosswind runway at our airport, either option (other airport/our crosswind runway) would have had me on the ground 2-3 minutes earlier but again, the critical nature of the situation wasn't obvious until the last 5-7 minutes of the flight and by that time I was over heavily populated unfriendly terrain with only a golf course and a highway as an out.

    Basic airmanship was fine, support from the wingman was pretty good although we have a lot of discipline when on ATC frequencies so I had to be pretty directive that I was not up for an overhead and needed a straight in, I also made a call when I started getting oil smoke in the cockpit - in terms of ADM the decision for immediate RTB is the saving grace, the rest is a series of learning opportunities that we will rotate into our training/briefing process.

    My survival/the planes survival was really only possible because I called the knock-it-off and RTB on the initial prop surge - had we pressed for even one more sequence the engine would have seized well short of the airport since each sequence takes about 4 minutes.

    It's pretty sobering alltogether.

    'Gimp

    4-14-18-7.jpg

    4-14-18-6.jpg

    4-14-18-3.jpg

    0416181541-a.jpg

    838.jpg

    4-14-18-4.jpg

    4-14-18-5.jpg

    4-14-18-8.jpg
     
    Last edited: Apr 18, 2018
    rvsuper8 likes this.
  2. Apr 18, 2018 #2

    smizo

    smizo

    smizo

    Moderator Staff Member Moderator

    Joined:
    Sep 7, 2009
    Messages:
    5,799
    Likes Received:
    2,995
    great write up and good job getting it back! lessons learned, nice work.
     
  3. Apr 18, 2018 #3

    StinsonPilot

    StinsonPilot

    StinsonPilot

    Supporting Member Supporting Member

    Joined:
    Nov 24, 2007
    Messages:
    3,166
    Likes Received:
    642
    Good job, consider the oil an anti corrosion coating!
     
  4. Apr 18, 2018 #4

    Larry Lyons

    Larry Lyons

    Larry Lyons

    Registered Users Supporting Member

    Joined:
    Oct 1, 2012
    Messages:
    3,664
    Likes Received:
    860
    Great write up Gimp, thanks.
     
  5. Apr 18, 2018 #5

    AcroGimp

    AcroGimp

    AcroGimp

    EAA 14, IAC 36

    Joined:
    May 8, 2012
    Messages:
    212
    Likes Received:
    43
    Forgot to clarify, the cockpit video shows oil temp, oil Px, and CHT all remained in normal range, and the prop governed through to shutdown. We do not suspect any damage to engine.

    We'll catch an oil sample; flush the system; dry fit the piston, seal and dome and exercise through the full range of the pitch change mechanism several times to ensure there are no previously unknown alignment issues in mechanism/hub/oil delivery tube, etc.,; and then conduct a Mx Check Flight overhead the field.

    Turned out as good as it could have but serious pucker factor, the 6-7 minutes from first oil on windscreen to touchdown were very 'high-alert', especially when I started getting a little oil smoke in cockpit, once I was short final and knew I had the field made I just transitioned to normal landing mode, and since the temps/pressures were OK elected to keep it running and taxi to hangar.

    'Gimp
     
  6. Apr 18, 2018 #6

    ssmdive

    ssmdive

    ssmdive

    Well-Known Member

    Joined:
    Mar 30, 2014
    Messages:
    964
    Likes Received:
    342
    I am clearly not an expert... But I'll act like one! The only three things I flinched a bit at were:

    1. Passing up the closer airport to fly over what I assume is a pretty packed city below. But this was just 3 mins.

    2. Dropping altitude when you think the engine might crap out instead of keeping it in the bank.

    3. Taxiing to the hangar instead of just shutting down right off the runway.

    But you are not bent, it is not bent... Good job! I hope it is an easy repair.
     
  7. Apr 18, 2018 #7

    rvsuper8

    rvsuper8

    rvsuper8

    Active Member

    Joined:
    Mar 23, 2017
    Messages:
    39
    Likes Received:
    5
    Great write-up, debrief, and self critique. Just some thoughts from the peanut gallery.

    You did not mention if your wingman gave you a once over with oil on your screen. They would probably have seen more than you and might have put you on a higher state of urgency then you felt you were in at the time, thus taking the closer airport.

    I do not know if this practice location is normal for your team or not, but of course low level formation acro over water not near a runway obviously puts you in a more precarious position. You cant always pick your practice locations when on the road, but IF you can, consider getting into a box over a runway for your day to day work to improve your odds. Its all about trying to improve the odds as best you reasonably can.

    Great job getting back on the ground safely. And very much appreciate your sharing for us all to learn from. A sign of professionalism.
    best,
    Mike
     
    Larry Lyons likes this.
  8. Apr 19, 2018 #8

    AcroGimp

    AcroGimp

    AcroGimp

    EAA 14, IAC 36

    Joined:
    May 8, 2012
    Messages:
    212
    Likes Received:
    43
    @ssmdive, I put it all out there because we talk about these things and yet in the heat of the moment that was how I reacted, some good, some not so good - hopefully we all can learn from it. I elected to taxi to hangar based on fact I had oil Px and temps were good, and hangar is about a minute from where I turned off, if either had not been good I'd have shutdown.

    @rvsuper8, we set a 1500' hard deck for acro practice and overwater is the most convenient location in our area - the nearest actual box is 40 minutes away and is also the only uncontrolled area in the area. From the spot we practice there is a Navy helicopter field that could be used in serious emergencies, with an engine failure or other significant issue we would shoot for it.

    'Gimp
     
  9. Apr 19, 2018 #9

    planebuilder

    planebuilder

    planebuilder

    Registered Users

    Joined:
    Jan 6, 2010
    Messages:
    733
    Likes Received:
    235
    Gimp, just thought I would thank you for the detailed account. It gives me more insight and awareness as the day (or year) gets closer, that I get my plane with the M462RF ( kinda close to your set up) flying. Glad you and your plane are ok!
     
  10. Apr 19, 2018 #10

    bonanzadrv

    bonanzadrv

    bonanzadrv

    Supporting Member Supporting Member

    Joined:
    Jan 17, 2007
    Messages:
    287
    Likes Received:
    36
    Gimp,

    Great write up and Great job!!

    Bill
     

Share This Page