for Savvy Account Managers and Analysts

  • What is this FEVA 2.0 report, why did my client get one, and what does it tell them?
    • A new benefit for SavvyMx, QA and SavvyAnalysis Pro clients.
    • Predicts the present condition of client’s exhaust valves: the probability of exhaust valve failure for each of their cylinders
    • Similar to the oil analysis report — it monitors the condition of an important component of the engine.
    • FEVA 2.0 is a screening test: it tells us when further investigation is warranted. It is not a diagnostic test to definitively determine valve condition.
  • Who gets the report, and when?
    • All clients subscribing to Pro, QA or Mx (not Breakdown, Prebuy or Pro Packs) who upload their data, and whose engine monitor captures a minimum set of data. Refer questions on the data to Chris.
    • When? Weekly we check for clients who have uploaded 5 new flights and send the report to them. No one can create a report on-line, on-demand yet. Coming later.
  •  How does FEVA 2.0 make predictions?
    • FEVA 2.0 uses “machine learning” trained on actual historical valve condition data and engine monitor data to “learn” what patterns in engine monitor data predict a higher incidence of valve failure.
    • Only Savvy has enough condition and engine monitor data to power a machine learning model (over 2.5 million flights and 12 years of maintenance management.)
  • How is FEVA 2.0 different from the original FEVA 1.0?
    • FEVA 1.0 only uses EGT. FEVA 2.0 uses EGT and 33 other variables.
    • FEVA 1.0 only reports when it detects a problem. FEVA 2.0 sends reports even if the valves are all normal.
    • In testing, FEVA 2.0 was about twice as good at detecting failing valves than FEVA 1.0, and about 50% better at avoiding “false alarms”.
  • How accurate is FEVA 2.0?
    • Valve failure is a rare event — we estimate 2% of valves are failing.
    • If FEVA 2.0 says a valve has an “above average probability” of being in failure, then it is about 5x more likely to be in failure than average. But because failure is rare, this means the valve has about a 1 in 8 chance of being in failure instead of 1 in 50 for the average valve. The report describes this clearly, but clients don’t read it. Don’t be mad at us if your valve is really OK, just be glad you’re not the one in 8.
    • If FEVA 2.0 says a valve has a “below average probability” of being in failure, then it is about half as likely to be in failure than average, about a 1 in 100 chance.
  • Why is it important to monitor exhaust valve condition?
    • Failure in flight can cause loss of power, especially significant in 4-cyl engines.
    • In rare cases, failure in flight could cause engine damage.
  • What action should I take based on the report?
    • Cylinders in the “above average probability of failure” category should be borescoped at the next scheduled maintenance (oil change, annual, 100-hr)
    • Cylinders in the “Average” or “Below average” categories should be borescoped at the next annual or 100-hr inspection (Savvy’s usual recommendation)
  • Does FEVA 2.0 tell me how to make my exhaust valves last longer?
    • No. FEVA 2.0 is a condition report, like oil analysis.
  • My valve is in the “Higher than average probability of failure” category. Am I doing something wrong?
    • Probably not. The pilot is rarely at fault when a valve fails.
    • If you would like us to review your engine management technique, ask for an analysis report.

More information here: https://www.savvyaviation.com/feva/

Revised 09/20/2020