SavvyAnalysis Puzzlers

It’s a logical question. You see something abnormal in the data and you wonder if your powerplant management triggered or provoked what happened. I’d say about a third of the tickets I work include some form of the question. Another popular question is “Should I have seen this coming?” and that’s more or less the mission of the monthly Puzzlers. When SavvyAnalysis Pro opened our doors 10 years ago we saw a lot of high CHTs in initial climb because pilots were leaning aggressively just after takeoff. Apparently they were anxious to set their cruise fuel flow for lean of peak – but doing it too soon. We don’t see that scenario as much these days. Exhaust valve failure is another one where pilots wonder if powerplant management triggered or provoked what happened. The legacy mindset was that high EGTs were causing valves to burn – just keep fuel flow high to keep EGTs lower and you won’t have burned valves. If that were true then we should see a far greater number of burned valves in low compression/higher EGT engines like the Continental O-470-R than in a high compression/lower EGT engine like the IO-520-K. And we don’t. (Mike Busch’s […]

I never watched MacGyver. It’s not like I watched it once and thought it was junk and never went back. I just never watched it. It must’ve been on when I was busy doing something else. But I think it’s cool that his name has entered the lexicon as a verb. People I know from all walks of life use the word when they cobble together a temporary solution to a problem. Sometimes the analysis team gets a scenario that we have to solve as a group. Usually the first analyst to see it will have a theory – or two – and just wants a second or third set of eyes to review the data and the thinking. We want to be confident that when we propose a remedy it, it’s going to be an efficient use of time and money and will resolve the problem. No MacGyvering.  First up is data from a Cessna P210 powered by a Continental IO-550TN with a Vitatoe mod, and data from an AuRACLE CRM 2100 with a 1 sec sample rate. EGTs on top, with CHTs and FF below. Cylinder 4 is the obvious problem, but there are a couple of details to point […]

When I taught in the classroom one of my favorite scenarios was teaching software. Typically I would introduce a concept, give examples of its application in the real world, and then show the students how to do it in the software. Inevitably, in a group of 25 students, there would be one or two who missed an important setting or step, and they were stuck. Sometimes the hand would go up right away. Sometimes you would see them look at the screen of the student next to them and try and figure out why that one was working but they were stuck. And then the hand went up. So the fun part as an instructor was the walk up. After a couple of years of teaching, I had seen all the rookie mistakes, and often I could spot the incorrect setting or the missing step before I even got to the student’s workstation. Of course, the real satisfaction in teaching came from the students who breezed through the exercise, and left the classroom knowing more than they did when they arrived. But there was something fun about quickly looking at the display of a stuck student and seeing the clue […]

Years ago my wife got a set of books as a gift. It’s the series devoted to sweating the small stuff in life. I guess the gifter thought she needed help prioritizing. They’re on the bookshelf in her office still shrink wrapped – so much for sweating. I’m not going to read them either, because writing a Puzzler is usually a deep dive into small stuff. Sometimes a small adjustment in cooling baffles can fix an engine that’s running too hot. What’s smaller than the orfice in an injector? But often cleaning one can solve a mixture distribution problem. A small fracture in a spark plug insulator can be the trigger for a detonation event. Airplane maintenance tolerances are often measured in thousandths. We’re all about the small stuff. Let’s start this month with a Cessna Turbo 210 powered by a Continental TSIO–520 engine and data from a JPI 830 with a 2 sec sample rate. Layout is the default of EGTs, CHTs and FF. This is a Savvy QA client. The analysis team supports Savvy Analysis Pro, Savvy Mx, Savvy Prebuy and Savvy QA. The issue was that the pilot couldn’t shut down the engine with the mixture control. […]

Judging from the ratings, I’m not the only one that just finished watching Succession. I’m an only child, and often wondered what it would be like to have siblings. Granted, it’s fiction, and granted it’s a supremely dysfunctional family, but wow. I’m fine with OC. As I reviewed the candidates for this month’s Puzzler, I noticed cylinders forming alliances, selfishness, pouty moods, tantrums, withdrawal – everything the Roys are famous for. We even had a case of backstabbing sabotage – an exhaust leak torching its downwind sibling. I admit it’s a stretch. The engine is just metal. Not complex like an heir or heiress. If you’ll allow me to torture this analogy a little more, that’s the draw of the show – the myth that if you had stupid amounts of money your life would be rich and full and strife-free. Guess again. It’s the stress the money brings with it that they don’t tell you about. And, back to engines, if you thought that adding bigger cylinders, or electronic ignition, or boost from a turbo would deliver you to the promised land of strife-free power, the data reveals that there’s still conflict in the C-suite forward of the firewall. […]

Most of the time engine data is an important tool for helping us with powerplant management during a flight, and choosing efficient options when maintenance is needed. If you’re a regular Puzzler reader, you’ve seen lots of examples of that. But every once in a while, the data is so erratic or mysterious that it can cause distractions or confusion. Every flight starts – or should start – with good preflight planning. For short trips, your planning might start a day or two ahead. For longer trips, you might start checking weather several days ahead, and maybe explore different options for rest breaks and fuel stops along the way. Ultimately all your planning leads to that moment when you start the engine and taxi out for takeoff and encounter the real-world weather and the airplane’s condition. Engine data helps us assess the airplane’s condition. This is taxi-out and runup data from the first 14 minutes of an hour and 25 minute flight of a Piper Saratoga powered by a Lycoming IO-540 and data from a JPI 830 with a 1 sec sample rate. EGTs, CHTs and FF. Nothing special about cursor placement – just getting it out of the way. […]

In a prebuy exam, the logbooks are the most important item to review. If the logbooks check out ok, reviewing a set of borescope pictures is a good next step. If there are no dealbreakers so far, take a look at the engine data – at least for the last couple of years. When a non-pre buy ticket comes with data from a test profile we’re looking at a specific flight. If we have a question about something, we might look back at a few flights or ahead a few flights for corroboration. But the goal is to take specific measurements and deliver a report using our standard report form.  With a pre-buy, we want to look at history and we’re looking for showstoppers. Persistent high CHTs, frequency and length of flights and data reliability as a proxy for attention to maintenance all have a story to tell. If you’re the seller, you want the data to confirm your good powerplant management skills, that the airplane is not a hangar queen, and that when a problem arises it gets dealt with. If your data does all that, your airplane is more valuable than one whose data isn’t as attractive. If […]

After ten years of reviewing engine data, it’s getting harder to hit us with something we haven’t seen before. This month we had the usual contingent of clogged injectors, weak spark and induction leaks. But we had a few scenarios that caused some head scratching, speculating and postulating. Since day one, our goal has been to keep the wrenches in the box unless we’re pretty certain that our recommendation will fix what’s wrong. In other words, we don’t like to guess. This month’s data from a Piper Seneca offered quite a Puzzle. Here’s data from the R engine of a Piper Seneca powered by Continental TSIO-360 engines with data from an EI CGR-30P using a 1 sec sample rate. Most engine monitors for twins give us data for the L and R engines in the same file. This installation gives us separate files for L and R. It’s easy enough to open them side by side for analysis, but that’s why you’re seeing R engine EGTs, CHTs, FF and oil temp – and not the L data. Sure gets your attention, doesn’t it? The cursor is hiding the data just before the runaway, but I wanted you to see the […]

As Savvy Analysis turns ten, I thought I would try and see if the data shows that more engine monitors and more data analysis over the last ten years contributed to fewer accidents attributed to mechanical failure. You would think so, right? Engine data should make it easier to recognize problems, and knowing what the problem is should impact the cost of fixing it – less shotgunning. I turned to the Nall Report which AOPA publishes annually and updates frequently. Nall Reports are archived here. Using data for non-commercial fixed-wing, the number of accidents fell from 1154 in 2012 to 892 in 2020 (the most recent year available). 334 fatalities in 2012 vs 273 in 2020. So that’s a good trend line, although you could argue that COVID had a big impact on data from 2020. Trying to answer my question, in 2012 there were 156 accidents attributed to mechanical issues. Of those, 55 were powerplant issues, with 1 fatality in that 55. In 2020 , there were 153 accidents attributed to mechanical issues. Of those, 77 were powerplant issues, with 10 fatalities in that 77. I don’t want to jump to conclusions based on two data points, and anecdotally […]

When we started Savvy Analysis Pro ten years ago, we wondered how long it would take before deep learning and artificial intelligence would take over and push the human analysts to the curb. In those ten years, we’ve rolled out Report Cards, Trend Analysis, reports, and three iterations of FEVA reports. Ten years ago we wondered how the computer would be able to identify and ignore bogus data. We’re closer to that now, as Mike Busch explains in his November article for AOPA Pilot. As 2023 dawns, watching Chat GPT explaining quantum physics and writing Haiku poetry, we’re probably a little closer to the curb than ten years ago. The Puzzler was born to examine unusual engine data. It was an homage to – ok, we stole the idea from – Click and Clack on NPR. They asked a question on one episode, then gave you the answer a week later. That format wasn’t going to work. Our format was to display some data, float some possibilities, then explain why one answer was correct, or at least more likely. We didn’t give you a week, you got the answer right away. But you could take as much time reviewing the […]

Chapter 6 of the AIM covers emergency procedures, including the difference between distress – like fire, mechanical failure, oil on the windscreen, or structural damage – and urgency – like being lost, low on gas, encountering dangerous weather, or any other condition that could adversely affect flight safety. And 6-1-2 ends with “Pilots who become apprehensive for their safety for any reason should request assistance immediately.” No argument there. If you’re reading this Puzzler I probably don’t have to convince you of the value of your engine monitor. But it does present the pilot with a lot more real-time information to process than the pilots of yore had to worry about. And sometimes you see something that doesn’t look right, even though performance is normal and everything else looks ok. You’re not ready to key the mic and ask for assitance yet, you’re not even sure there’s a real problem. You just know something doesn’t look right. It’s time to declare – if only to yourself – an anomaly. For example, let’s say you’re cruising along and making good time and you notice fuel flow indicates zero. Not fuel quantity – not what’s in the tanks – but fuel flow to […]

Good news! They’re making Spinal Tap 2, with plans to release it in 2024 – 40 years after the first one. Of all the great quotable lines in ST1, it’s hard to top “these go to eleven”. Sometimes we get a set of screwy engine data that makes us wonder if the data came from one of those “eleven” monitors. When I’m working tickets, I find they fall into three basic categories. First is when I see something familiar, like a clogged injector or weak spark in one of the plugs. Sticky valves are getting easier to spot. Failed and failing probes are usually easy to spot. Second its when I see something that isn’t as familiar, but makes sense in the context of the details on the ticket. Examples are induction leaks, vapor lock, and loose baffles and other cooling problems. The third category are the ones that require a deeper dive. Something is happening and we’re not seeing it in the data. At least not initially. Well start November with one of those. First up is data from a Bonanza 35 powered by a Continental IO-520 engine with data from a JPI 900 with a 1 sec sample […]

A lot of analysis requests begin with “Something bad just happened and we had to divert and land. Is there something in the data that would’ve told us this was about to happen?” Our first reaction is usually relief – that the pilot got on the ground safely and is able to make the request. Then the forensics begin and we start looking through the data for clues. Sometimes the warning signs are obvious. January’s Puzzler tells the story of a 172 making a cross-country trip, with oil pressure dropping at every stop. Eventually the engine quit and the airplane landed in a field. Sometimes the warning signs aren’t obvious, at least to the trained human eye. Savvy Ai is using machine learning to look for patterns and trends that elude detection using our current graphic depictions. Meanwhile, let’s look at some recent events and see what the data can tell us. You’ll notice a different look to the screenshots this month. I’m using the new beta version of the flight data page. First up is a Cessna Turbo 206 powered by a Lycoming TIO–540 and data from a Garmin G1000 with a 1 sec sample rate. This is the […]

Baseball has the cycle – single, double, triple and home run. What would that be for an analyst working a shift? Clogged injector is probably the single. Bad spark plug is probably the double. Let’s say the triple is a stuck valve. And the homer is a detonation event. How about a catastrophic part failure? Clearly a broken bat hit. Foul ball is a failed probe. Still working on the analysis equivalent of a bunt. This month’s puzzler isn’t exactly a cycle, but it should keep you thinking. First up is a Cessna 170 powered by a Continental O-300 and data from am EI CGR-30P with a 1 sec sample rate. EGTs, CHTs and FF. Nothing special about cursor placement – just midway through the flight. The things that jump out are — EGT 2 is high whenever the engine is making power – during idle it drops down with the others. CHT 2 is a little lower than 3 and 4 which are hottest. CHTs 5 and 6 are abnormally low, in the 200 range in cruise. But EGTs 5 and 6 are right there with the others, suggesting that the low CHTs are because of cooling and not […]

Apparently the 80/20 rule is also known as the Pareto Principle. Broadly applied, it means that 20% of your activities will account for 80% of your outcomes. In my previous careers in advertising and education, I would contend that 80% of stuff I spent my time on were caused by 20% of my ad clients – or students. After nearly ten years of reviewing engine data, I’d say about 80% of our tickets are either fuel issues, spark issues or bad sensor data. That’s good news for our clients, because both are relatively easy to fix, and good news for SavvyAnalysis because those are usually easy to spot and we can deliver a quick and accurate diagnosis. But when the Puzzler deadline rolls around each month, it’s the other 20% that are usually more interesting to write about. This month we’ll look at data from a Piper Saratoga, an RV-6, a Cessna 414, and a Cessna 182. First up is data from a Piper Saratoga with a Lycoming IO-540 engine and data from a JPI 700 with a 6 sec sample rate. Even though the older JPI’s shipped with a six second sample rate, we advise clients to reset that […]

It’s always fun at Oshkosh when one of the technologies of GA makes a move after spending a lot of time on the plateau. Avgas is the latest example. For years we just pumped it and worried about the short-term cost and the long-term availability, and now we’ve got some interesting new options to consider. A few years ago it was electronic mags. Before that, glass panels, electronic flight bags, flow-balanced injectors, active noise reduction headsets – the list goes on. It feels like we’re at a plateau with engine monitors. For the past thirty or so years we’ve had the same basic thermocouple sensors to gather EGTs and CHTs, and other types of pressure and flow sensors for other engine data. Garmin just made an improvement in their manifold pressure sensors for the G3X Touch, but adding a snubber is more like a small step than a giant leap. (Sorry, I get this way every time an Apollo 11 anniversary rolls around.) Displays are certainly prettier now, and with most units you can program alarms to warn you of trouble. Maybe this Oshkosh will bring a surprise from the engine monitor direction. Meanwhile, we’ve got puzzles to solve. First […]

I’m not spoiling the movie if I tell you that one of the opening scenes of Top Gun: Maverick is a pilot swinging a wrench on an owner-flown piston-powered warbird. That may be enough to make you want to see it, although from the box office numbers so far they don’t need help filling seats. The camera point of view is from the other side of the plane, so naturally the engine data geek in me wondered if he was changing out a faulty probe for his state-of-the-art digital engine monitor. Hey, a guy can dream. It’s tempting to go off on a rant about how GA is often depicted in the movies, but that’s not why you’re here. So let’s look at some data from recent flights. First up this month is data from a Cessna 172RG powered by a Lycoming IO-360 and data from a JPI 700 with a 6 sec sample rate. Cursor is on the beginning of the CHT 3 excursion. FF is logged in liters per hour – 46 LPH is 12.1 GPH. That climb in CHT 3 is from 325º to 525º – exactly 200º – in just over 4 minutes. Can we trust […]

The Greek poet Archilochus wrote, “The fox knows many things, but the hedgehog knows one big thing.” I’m reminded of this when clients ask “Which engine monitor should I buy?” Savvy doesn’t endorse brands or product models, so without naming names, we think the best choice is the one that reliably gives you the information you want in real time and then makes the download/upload process easy to accomplish. On that last point, I know some clients want a system that automatically connects to a wi-fi network and seamlessly uploads new engine data as they taxi down their hangar row. For me, downloading to the thumb drive comes right after mixture and mags, and before master off. Whichever model gets you to do it – that’s the one you want. To generate a report we use EGT, TIT, CHT, FF, RPM, MAP, Oil pressure and Oil temp, OAT, and Bus Voltage – x2 on a Cirrus. GPS Altitude is nice to have to verify what looks like a climb or descent. Sometimes Fuel Pressure is helpful when diagnosing a fuel issue. Carb temp is often helpful when ice is suspected. Those parameters pretty well define the hedgehog monitor, at least […]

We’ve seen an increase in issues related to induction lately. Is it because many airplanes spent more time grounded because of the virus, and issues are emerging as the hibernation is ending? Or maybe it’s just that for most of our US-based clients, temperatures are warming and taking their toll on clamps, sleeves and gaskets. Whatever the reason, we’ll spend this month looking at what’s different about data from induction leaks. It’s tempting to drift into the mechanics of an induction leak, but I’ll stick to how to spot it in the data. John Deakin, Mike Busch and others have written extensively on plumbing, Bernoulli and Venturi if that’s what you’re after. I’ll drift this far – when your MAP gauge is showing 12″ at idle, and ambient pressure is around 29″, your gauge is measuring suction. More accurately, it’s measuring how much of that ambient pressure it’s keeping out of the engine. Knowing that, and before looking at any data, what if we see idle MAP up around 16-17″? It means that for a normally aspirated engine – carb or injectors – air is getting past the closed throttle plate and into the engine. What about turbos? At idle, […]

Are you playing Wordle? It’s fascinating to me how this puzzle has caught on as we look for distractions from that other 5-letter word that begins with C and ends with D and has two non-adjacent vowels. What has this got to do with analysis? Well, sometimes – actually, most of the time – we get symptoms and we’re pretty sure what it is, and it turns out we’re correct. Call it 1/6 or sometimes 2/6. We love those green tiles. Other times, it feels more like 4/6 or 5/6 as we sift through the options.  Do you have a favorite starting word? I have one friend that insists that vowels are the key, so starts with words like adieu and canoe. A different friend insists that if you get the consonants right, the vowels fall into place. Hw mprtnt r vwls anhw? We’ll start this month’s Puzzler with one of the more unusual scenarios we’ve seen. This is from a Cessna 180 with a Continental O-470 and data from an EI CGR-30P with a 1 sec sample rate. Here are EGT, CHT and FF for three flights with about a week between them. Nothing special about cursor placement. The […]

Recently I saw an ad for a furniture store encouraging me to “kickback in style”. I remember hearing that word a lot as a term for relaxation when I moved to southern California in the early 80s. Before moving, I had read that word a lot in the Chicago papers in regards to unscrupulous public servants. And years before that, it was what my Royal Enfield 750 liked to do on cold mornings. In the world of aviation, we usually hear it in regards to starters – and it’s usually not good news. Usually engine starts happen before the avionics bus goes to ON and before the engine data monitor starts logging – which is why you’ll rarely see engine starts as a topic in this column. But I do have a good one for you. Recently Savvy account manager Dean Showalter discussed a problematic engine start event that resulted in a cracked starter housing on his Airplane Owner Maintenance podcast. Dean and I worked together on a ticket for a 172, and that’s where we’ll start this year’s set of puzzles. First up is data from a Cessna R172K Hawk XP with a Continental IO-360 and data from a […]