{"id":3243,"date":"2025-10-18T07:12:06","date_gmt":"2025-10-18T07:12:06","guid":{"rendered":"https:\/\/aps-eb.de\/?p=3243"},"modified":"2026-02-12T14:05:52","modified_gmt":"2026-02-12T14:05:52","slug":"oelanalyse-richtig-lesen-so-triffst-du-kluge-wartungsentscheidungen","status":"publish","type":"post","link":"https:\/\/www.aps-eb.de\/en\/oelanalyse-richtig-lesen-so-triffst-du-kluge-wartungsentscheidungen\/","title":{"rendered":"Read oil analysis correctly \u2013 how to make smart maintenance decisions"},"content":{"rendered":"
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Summary:<\/strong> A single oil analysis is a snapshot. The trend decides<\/strong>.
Pay attention Wear metals<\/em>, Fuel dilution<\/em>, silica<\/em>, viscosity<\/em>,
Water\/glycol<\/em> and Acid\/base numbers (TAN\/TBN)<\/em>. In case of anomalies: narrow down the cause, check in a targeted manner,
re-sampling after a short period of time.<\/p>\n<\/header>\n

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Why oil analysis makes sense for ELA1 pilots<\/h2>\n
    \n
  • Early detection of bearing, cylinder and valve wear.<\/li>\n
  • Evaluation of the Operating mode<\/strong> (cold run, high DA\/heat, \u2018lean of peak\u2019, Mogas\/Avgas).<\/li>\n
  • Well-founded TBO\/On-Condition Decisions<\/strong> \u2013 Trends are evidence.<\/li>\n
  • Measure the effectiveness of interventions (time of ignition, prop balance, ring change).<\/li>\n<\/ul>\n<\/section>\n
    \n

    How to Take a Usable Sample<\/h2>\n
      \n
    1. Warming up<\/strong> (> 70 \u00b0C), sample directly after parking.<\/li>\n
    2. When leaving it Middle beam<\/strong> catch (not first\/last drops).<\/li>\n
    3. Clean laboratory bottle, gloves; Funnels only unique<\/strong>.<\/li>\n
    4. Flight Hours, Oil Type\/Brand, Refill Quantity<\/strong> indicate on the form.<\/li>\n
    5. At the latest after 48 h<\/strong> send.<\/li>\n<\/ol>\n

      Tip: Always The same laboratory<\/strong> and The same oil<\/strong> use \u2013 this cleans up trends.<\/p>\n<\/section>\n

      \n

      Key metrics \u2013 briefly explained<\/h2>\n
      \n\n\n\n\n\n\n\n\n\n
      block<\/th>\nTypical parameters<\/th>\nAn increase means<\/th>\nCheck immediately<\/th>\n<\/tr>\n<\/thead>\n
      Wear metals<\/strong><\/td>\nFe, Cr, Ni, Al, Cu, Sn, Pb<\/td>\nFe<\/strong> Steel\/Courses \u00b7 Cr\/Ni<\/strong> Rings\/Valves \u00b7 Al<\/strong> Pistons \u00b7 Cu\/Sn<\/strong> Bearing\/bronze \u00b7 Pb<\/strong> Bearing\/AvGas residue<\/td>\nCompression\/leak-down, endoscopy, slicing oil filter<\/td>\n<\/tr>\n
      contaminants<\/strong><\/td>\nSi, Insolubles, Ash<\/td>\nSi<\/strong> = dust \/ dirt \u2192 intake air \/ leaks<\/td>\nAir filters, intake pipes, hoses\/clamps<\/td>\n<\/tr>\n
      Fuel & Water<\/strong><\/td>\nFuel dilution %, Water\/glycol<\/td>\nFuel dilutes oil (cold run, rich operation); Glycol in liquid-cooled Rotax<\/td>\nCold start\/hot run, carburettor\/EFI, cooling circuit<\/td>\n<\/tr>\n
      Oil condition<\/strong><\/td>\nViscosity 40\/100 \u00b0C, TAN, TBN<\/td>\nViscosity \u2193<\/strong> Fuel\/Wear \u00b7 TAN \u2191<\/strong> Ageing\/corrosion \u00b7 TBN \u2193<\/strong> Additives consumed<\/td>\nInterval, operating profile, venting<\/td>\n<\/tr>\n
      additive<\/strong><\/td>\nCa\/Mg\/Zn\/P<\/td>\nVaries per oil; Jumps = oil change\/top-up<\/td>\nMatch history<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

      Limit values are model- and laboratory-specific \u2013 more important than absolute numbers is the Comparison with Your Predictions<\/strong>.<\/em><\/p>\n<\/section>\n

      \n

      Read lab report - in 5 steps<\/h2>\n
        \n
      1. Plausibility check:<\/strong> Oil type, runtime (h\/day), refill quantity.<\/li>\n
      2. Trend view:<\/strong> Comparison with 3-5 previous samples (similar runtime!).<\/li>\n
      3. Cluster:<\/strong> Do e.g. Fe + Cr + Ni rise together? \u2192 friction partner\/cylinder.<\/li>\n
      4. Assign source:<\/strong> Use the table above (Pb+Sn \u2192 Stock, etc.).<\/li>\n
      5. Action & Re-Test:<\/strong> define the measure, in 10-25 h<\/strong> Sampling again.<\/li>\n<\/ol>\n<\/section>\n
        \n

        Typical findings & what you do<\/h2>\n
          \n
        • Fe \u2191 + Cr moderate \u2191, Viscosity \u2193<\/strong> \u2192 Friction + fuel dilution.
          Action:<\/em> Test mixture\/run-up, avoid cold running, oil change, re-test 15-20 h.<\/li>\n
        • Si clear \u2191 + Al easy \u2191<\/strong> \u2192 dust; React piston\/raceway.
          Action:<\/em> Air filter\/seal suction, endoscopy, re-test.<\/li>\n
        • Cu + Sn \u2191, Pb \u2191<\/strong> \u2192 bearing\/bronze; Possibly AvGas effect.
          Action:<\/em> Cut open oil filter, check vibration\/ignition, leak-down.<\/li>\n
        • Fuel dilution > 2\u20133\u00a0%<\/strong> or Viscosity strong \u2193<\/strong> \u2192 a lot of short distance\/rich.
          Action:<\/em> Adjust operating profile, carburettor\/EFI setting, short interval.<\/li>\n
        • TAN \u2191 + Insolubles \u2191<\/strong> \u2192 Oil ages\/humidity\/maintenance.
          Action:<\/em> Interval shortening, dehumidification, longer warm runs, winter preservation.<\/li>\n<\/ul>\n

          Rotax Note (912\/914\/915):<\/strong> AvGas share > 30\u00a0% increases the need for maintenance; The interval between 25 and 50 h. Burp procedure and clean sampling are essential.<\/p>\n<\/section>\n

          \n

          Decision Matrix (simplified)<\/h2>\n
            \n
          • Single, slight abnormality<\/strong> (without trend) \u2192 continue flying, re-test in 15-25 h.<\/li>\n
          • Several metals rise together<\/strong> \u2192 Additional checks (compression\/endoscope\/filter cut), short interval, re-test.<\/li>\n
          • Strong jump + symptoms<\/strong> (vibration, oil consumption, metal in the filter) \u2192 ASAP workshop diagnosis.<\/li>\n
          • Glycol\/water detectable<\/strong> \u2192 fly no further, fix cause.<\/li>\n<\/ul>\n<\/section>\n
            \n

            From the hangar<\/h2>\n
              \n
            • Prop balances:<\/strong> Fe\/Cr trend flattens, CHT spread improves \u2192 measurable effect.<\/li>\n
            • Leaky intake gasket:<\/strong> Si peak in two samples; Normalized after gasket replacement.<\/li>\n
            • Training organisation:<\/strong> High fuel dilution + low viscosity; Profile adjusted \u2192 values stable.<\/li>\n<\/ul>\n<\/section>\n
              <\/section>\n
              \n

              FAQs<\/h2>\n

              How often do you sample?<\/strong> At least for oil change; additionally after interventions or in case of abnormalities early.<\/p>\n

              Which runtime per sample?<\/strong> As constant as possible (e.g. 40-50 h), otherwise trends are difficult to compare.<\/p>\n

              When is a value \u2018too high\u2019?<\/strong> If it runs against your trend or multiple partners rise together. Laboratory flags are clues, not judgments.<\/p>\n<\/section>\n