AVwebFlash - Volume 14, Number 38b

September 18, 2008

By The AVweb Editorial Staff
Win a Brand-New Ford Mustang GT Convertible!!!
Every Genuine Factory Engine purchased from Air Power, Inc. between September 8, 2008 and July 20, 2009 automatically is entered to win a Brand New Ford Mustang GT Convertible! For official rules and details, visit Air Power online at the web site FactoryEngines.com or call Air Power at (888) 759-4295.

Don't forget: Air Power's First-Ever, Zero-Down Factory Engine Financing makes it easier than ever to get the Factory Engine you've always wanted!
Top News: Eclipse 500 Hearings on Capitol Hill back to top 
Sponsor Announcement

House Panel Investigates Eclipse Certification

A congressional committee on Wednesday heard a litany of concerns about the FAA's oversight of the certification of the Eclipse very light jet, including a report that the FAA okayed the jet for a single pilot even though the FAA's Flight Standardization Board had determined that the aircraft required a two-pilot crew. The House Aviation Subcommittee heard from Calvin Scovel, the Inspector General for the Transportation Department, who said his investigation showed that FAA employees were given "marching orders" by management and a target date was set for the jet's certification. "It was a calendar-driven process ... with a predetermined outcome," he said. He added that FAA Administrator Robert Sturgell told him that the FAA, which recently completed a "special review" of the E500's type certificate, will also review the production certificate. When asked by U.S. Rep. Robin Hayes, of North Carolina, if the Eclipse jet is a safe airplane to fly, Scovel responded, "My office has no evidence that it is unsafe." Scovel later said that given the information that was available to the FAA on Sept. 30, 2006, when it awarded the type certificate, "a reasonable decision would have been to defer the granting of the type certificate."

Among the concerns cited by the committee were avionics software issues; the lack of a drainage system for the pitot-static system, which made it subject to clogging from ice; intermittent false stall warnings; blanking or freezing of the cockpit displays; and flaps sticking in position. The committee also noted that the European Aviation Safety Agency, which normally certifies aircraft "automatically" if they are approved by the FAA, declined to do so with the EA500, and is conducting its own testing and review of the aircraft. The Inspector General said there are "inherent risks" associated with a new aircraft utilizing new technology, produced by a new manufacturer, and marketed with a new business model for its use, and the FAA should have exercised heightened scrutiny in certifying the aircraft.

Based on the interim results of the Inspector General's investigation, he recommended that FAA (1) reassess the propriety of its single-pilot certification for the EA500, (2) expedite its Notice of Proposed Rulemaking to clarify certification requirements for VLJs, (3) evaluate the propriety of allowing new, inexperienced manufacturers to certify their own aircraft for airworthiness prior to design certification, (4) discontinue prioritizing specific manufacturers' programs in its Performance Plan to avoid the appearance of favoritism or the perception of diminished vigilance in its oversight mission, and (5) implement a "cooling-off" period for its aircraft certification safety inspectors and engineers before allowing them to accept positions with the manufacturers they formerly regulated.

The committee heard from a panel of current and former FAA staffers who described a pattern of pressure from FAA management to meet the timeline for Eclipse certification. FAA software engineer Dennis Wallace said he had reported that the E500's software was not ready to be certified, and was "surprised" to hear that the type certificate was awarded anyway, on a Saturday afternoon. He described a meeting where staffers were told they were expected to "save the company" -- meaning Eclipse -- and said there was strong pressure from FAA management to certify the jet on time. David Downey, who was in charge of the Eclipse program for the FAA until he was removed by upper management, said he and others felt "trapped," and that in his years at the FAA, "nothing else comes close" to the kind of pressure that was brought to bear on Eclipse's behalf. "No Eclipse tactic was out of bounds," he said. After Downey was removed from his position, FAA headquarters required him to undergo a "peer appraisal," and the Eclipse chief operating officer was among those certifying his performance. "It would appear that this was an obvious conflict of interest," the committee said in its report. Downey has since left the FAA for the private sector. Other FAA staffers testified that they believed bonuses and other benefits for FAA managers were tied to awarding the type certificate by the end of the fiscal year. Rep. Leonard Boswell, of Iowa, told the FAA employees who testified to contact him personally if they experience any retribution from the FAA.

A common theme during the hearing was that the FAA must move away from its "customer service" model, which has led to too-cozy relationships with manufacturers, and ensure that public safety remains the agency's number-one priority. The committee also encouraged management to do a better job of listening to objections from its staff. A panel of FAA officials said they would work toward improving in those areas. Near the end of the lengthy proceedings, Peg Billson, general manager of the Eclipse manufacturing division, was called to testify. She said that nobody at Eclipse Aviation was interviewed for the Inspector General's report, and she hoped to clear up misconceptions and misinformation about the company and the airplane. "It was a very confused and frustrating time," she said of the certification process. She said that she gave the FAA test pilots "an immature airplane" to evaluate, and their concerns were based on the characteristics of that non-conforming aircraft. "We had some false starts," she said. Rep. Boswell told Billson the Inspector General's report, and the hearing, were not about Eclipse, but about the FAA and their procedures. "It's our role to provide aggressive oversight to ensure that the FAA is doing their job," he said.

For more information:

  • Click here to read the committee's summary of the topics to be covered in the hearing. (PDF)
  • Click here to read a summary of the Inspector General's report, with a link to the full text.
  • Click here to watch the archived video from the hearing (all five hours of it).
  • Click here to read the printed testimony from the FAA's Nicholas Sabatini, associate administrator for aviation safety.
  • Click here for the written testimony from NATCA President Pat Forrey. (PDF) Forrey did not appear at the hearing, but Aircraft Certification National Representative Tomaso DiPaolo was there as NATCA's representative.

Introducing AV8OR™ from Bendix/King by Honeywell
The AV8OR is the portable and affordable GPS built specifically for pilots, by a company that knows pilots. With navigation routing, planning and weather information for the aircraft and the automobile, the AV8OR uses aviation software and symbology pilots understand. Its 4.3-inch touch screen is larger and easier to read than competing GPS systems, with an intuitive interface derived from the pilot-friendly, panel-mounted Bendix/King multi-function display systems. For more information, go online.
Eclipse Clarifies Its Position back to top 

Eclipse Responds To Inspector General Report

Although the congressional panel that met in Washington on Wednesday said the issue wasn't Eclipse, but the FAA's allegedly inadequate oversight and flawed procedures, Eclipse Aviation has issued a "fact sheet" in response to the inspector general's testimony and other matters that arose at the hearing. The fact sheet, which is posted at an Eclipse Web site called eclipsefacts.com, disputes several statements made by the inspector general. It's not true, Eclipse said, that problems with the jet's tires occurred because they were designed for landings on soft fields. The tire supplier failed to meet durability standards as promised, Eclipse says, and a change in tire type is pending. Also, Eclipse says it's not true that EASA has declined to certify the EA500 to fly in Europe -- that certification is now in the works and is expected within 60 days. Eclipse notes that a statement was made at the hearing that one pilot who flew for Eclipse's largest customer [DayJet, which flies all the jets with two-pilot crews] "lacked the confidence that the aircraft could be operated safely by a single pilot." Eclipse says this is hearsay and "selectively choosing a single pilot to push the agenda of changing the Single Pilot certification of the Eclipse 500." However, the inspector general's report also states that the FAA Flight Standardization Board determined, prior to FAA certification, that the aircraft required a two-pilot crew.

Eclipse also said that the results of the FAA's Special Certification Review confirmed that the Eclipse 500 is safe and was properly certified. "The Eclipse 500 is one of the safest and most tested aircraft ever introduced into the market," the statement says. "The safety record reflects relatively small incidents and no injuries or fatalities. This safety record is a testimony to the fact that the aircraft was certified correctly following FAA established procedures, testing and certification requirements."

Aircraft Spruce West Holds Annual Super Sale & Fly-In
Join the Aircraft Spruce Team Saturday, September 27, 2008, 7am-3pm in Corona, California. It's that time of year when Aircraft Spruce offers spectacular discounts on their most popular products and a chance for customers to meet vendors. Enjoy seminars by Garmin, Team Nemisis, the FAA, and Aircraft Spruce's Avionics Specialist Ryan Deck. Aircraft will be on display, and hourly raffles will be held. Call Aircraft Spruce at 1 (877) 4-SPRUCE, or visit online.
In the Wake of Hurricane Ike back to top 

Lone Star Museum Heavily Damaged By Ike

While Hurricane Ike has faded from memory for most of the country, those hit by the storm will think of little else in coming weeks as the cleanup goes on. In the aviation world, nowhere did the storm wreak more havoc than at the Lone Star Flight Museum, in Galveston. As we mentioned in earlier issues, the museum took a direct hit but the scope of the damage wasn't clear until we received these photos from a reader there. As much as eight feet of water filled some of the facilities and priceless aircraft were inundated. According to a report from the museum, the inventory in the gift shop was destroyed, as were many exhibits. The major need now is fresh water to flush out the aircraft that were hit by the storm surge. Of course, the buildings took a major pounding too and extensive repairs will be required. Some aircraft were moved in advance of the storm and are fine.

Click here to view photos.

Pilots Asked To Help With Hurricane Aftermath

General aviation pilots are often frustrated in their efforts to lend a hand with their aircraft after a natural disaster, but Fred Quarles, of Operation Teacup, is welcoming help from willing aircraft owners. Volunteers can expect "No pay, no thanks, hard work, little sleep, and all the alligators you want," Quarles said this week. "The bonus is all the armadillos you want, and expenses are tax deductible." Volunteers can visit his Web site and sign up via e-mail, and Quarles will contact you with flight assignments. Pilots are needed to fly medical evacuation flights into Texas and Louisiana and to take supplies to Haiti and the Bahamas. If volunteers have spare rooms at home, they are welcome to take home a few people and give them a dry place to stay and a few meals till things settle down and they can go home. There are about 40,000 people homeless just in the Houston area, Quarles said.

This is a big job and may last for several months. "We will have a party when the work is done," he said. For more information, contact Quarles at (434) 220-4880.

Trade-A-Plane Features Thousands of Classifieds, Updated Hourly
With thousands of hourly updated Classifieds, a Product & Advertiser Index, Forums, NAAA Evaluator, Performance Database, Spec Sheets, and Aviation Weather, Trade-A-Plane gives you everything that keeps you flying. Order your Trade-A-Plane subscription by calling (800) 337-5263, or go online.
The Latest on Thielert back to top 

Thielert Engines Update

The Thielert engine factory in Liechtenstein is continuing to build and deliver diesel engines and spare parts while sorting through various offers from new investors who hopefully will rescue the company from insolvency, company representatives told the media in a conference call from Europe on Tuesday. Asked whether a new owner will honor the warranties that are currently worthless paper in the hands of engine owners, spokesman Christoph Moller said that will be up to the new investors to decide. "We are not authorized to tell the new investors what to do with their company," he said. Gunter Kappler, head of technology at Thielert, said that even if Diamond Aircraft switches to their own Austro diesel engine, as they have said they plan to do, Thielert has enough other customers to keep the company viable. Also, the company is focused now on extending the life of life-limited components from 300 hours to 600 hours, though Moller said he couldn't give a timeline for when that goal would be reached. He also said it would be up to the new investor to figure out the problems associated with a lack of service centers in North America -- engines now must be shipped to the factory in Europe for inspection and repair. And he added that since the factory is still operating and the service center is open, "There is no reason from our side that aircraft are AOG" -- a claim that aircraft owners whose Thielert engines are now up against life limits and no apparently viable options to keep them in the air, are sure to dispute.

Todd House, the founder of the Thielert Engine Owners Group, also called in to the conference, but his questions were politely defrayed by the company representatives. "This is a press conference, and you are welcome to listen in, but we are taking questions from the media only," they said. They added that a meeting with representatives from the owners group is scheduled for later this week and all of House's concerns would be addressed at that time. For more on this story, click here for analysis from Paul Bertorelli, editor-in-chief of Aviation Consumer, in the AVweb Insider Blog.

Aircraft Financing to Fit Your Needs
AirFleet Capital offers a competitive and experienced approach to each and every loan program by focusing exclusively on aircraft financing. AirFleet Capital provides exceptional terms coupled with personal service and a long-term commitment to support the business and shared passion of aviation. From Light Sport Aircraft to VLJs and Business Jets, AirFleet Capital has a loan program to fit your needs. Call an AirFleet Capital financing specialist at (800) 390-4324, or request a quote online.
News Briefs back to top 

NTSB Wants Better-Trained Pilots And Seatbelts For Skydivers

The NTSB on Tuesday released a special report identifying several recurring safety issues with parachute jump operations, and recommended improvements in aircraft maintenance and pilot training. The report was prompted by a crash in July 2006 in Missouri, when an engine failed shortly after takeoff in a de Havilland DHC-6-100. The pilot and five parachutists were killed, and two other parachutists were seriously injured. Since 1980, 172 people have died in 32 skydiving-related accidents that had nothing to do with the act of actually jumping from the airplane and deploying the chute. The board found a "pattern of safety deficiencies" in aircraft maintenance, pilot training, and FAA oversight. For example, the board found in its final report on the 2006 accident, released this week, that more parachutists may have survived if better restraints had been used. "This clearly emphasizes the importance of implementing our recommendations designed to increase survivability when an accident does occur," said NTSB Acting Chairman Mark Rosenker.

The board made recommendations to the FAA and USPA regarding dual-point restraint systems for parachutists. "As this activity increases in popularity, we have to ensure that safe operations are adhered to by all operators," said NTSB Acting Chairman Mark Rosenker. "Our recommendations in the areas of maintenance and training will move this industry forward in preventing these types of accidents."

On the Fly ...

More than $7,500 in donations were collected to cover the lost pay of an American Airlines pilot suspended for allegedly taxiing too slow. A supervisor pilot was taxiing behind him and initiated the suspension for what he said was the other pilot's failure to clear a runway fast enough ...

A leaked report says the flaps on a Spanair MD-82 that crashed on takeoff in Madrid last month were not in the takeoff position. The report also said a cockpit warning that should have alerted the pilots did not work ...

Prince William will follow in the footsteps of his uncle, Prince Andrew, and fly a military helicopter. William will be deployed on Apache attack helicopters.

Win This Plane!
Enter AOPA's 2008 Sweepstakes and you could be flying high in a fully refurbished Piper Archer II, accented with a new instrument panel featuring the world's first installed certified EFD1000 PFD. Custom extras include handcrafted leather seats, tie-down rings, nav light retainers, and wood trim accents. Click for more details.
Interact! We Want to Hear Your Voices back to top 

Question of the Week: Helping Out with Your Airplane

This Week's Question | Previous Week's Answers


Last week, on the seventh anniversary of the World Trade Center terrorist attack, we asked AVweb readers to give us their opinion on air security today.

34% of those who took time to answer our informal poll agreed with the assessment that security is improved greatly, but there are still holes that determined terrorists could exploit. Other opinions were scattered pretty evenly across the various options we provided, including 14% of readers who chose the perennial OTHER (my opinion doesn't appear as a choice).

For a complete (real-time) breakdown of reader responses, click here.
(You may be asked to register and answer if you haven't already participated in this poll.)


With so many members of the general aviation community donating their time, skills, money, and resources to the hurricane recovery effort in Texas, we'd like to know how much volunteering you've done.

Have you ever used your airplane for humanitarian purposes?
(Click to answer.)

Have an idea for a new "Question of the Week"? Send your suggestions to .

This address is only for suggested "QOTW" questions, and not for "QOTW" answers or comments.
Use this form to send "QOTW" comments to our AVmail Editor.

How to Find Cheap(er) Gas

There's no such things as cheap gas. Nonetheless, prices vary as much as $3 per gallon from one FBO to another and that's more than $100 on a typical fill-up. Our sister publication, Aviation Consumer, is conducting a survey on how pilots find the best prices on gas.

To chime in, e-mail avconsumer@comcast.net.

(The results will appear in a future issue of Aviation Consumer. For subscription information, click here.)

Does Your Aircraft Insurance Provide $5,000.00 in Legal Costs?
When you insure with Avemco®, you get up to $5,000.00 in legal defense costs if the FAA or civil authority takes pilot certificate enforcement action against you for a covered loss or accident. To get your no-cost quote, call Avemco at (888) 241-7891, or click here to visit us online.
New on AVweb back to top 

EGT and CHT Interpretation

We go beyond the basics in this article on getting the most out of your digital engine-monitor system.

Click here to read this maintenance article.

The most important reason to have a multi-probe engine-diagnostic system is the in-flight diagnostic capability that such a system brings. If the pilot knows and understands the system, a multi-probe cylinder head temperature/exhaust gas temperature (CHT/EGT) system can serve as an unparalleled "early warning" device, pinpointing the location and nature of various types of engine problems (sometimes) long before they show up in other ways.

Of course it also helps visually quantify precise leaning by the pilot. With the cost of gas so high, we want every drop of liquid dinosaur that we can get to perform useful work without frying cylinders. These multi-probe systems go a long way toward that end.

The key is to know and understand the system. It takes a good deal of experience with a particular system, and a thorough grounding in the principles of exhaust analysis, to use a CHT/EGT system to maximum advantage. All the manufacturers have published detailed brochures on understanding their products. There are also courses.

In this article, we'll explore some of the more common "mechanical gremlins" that can be diagnosed on such a system. For illustration purposes, we have chosen to use a generic, bar-graph-type display (similar to either Insight, EI or JP Instruments) in which the top stack of lit bars represents the EGT for a particular cylinder, while the non-illuminated bar within each stack represents separation between the EGT stack above and the corresponding CHT stack below.

The principles described below apply to all multi-probe systems, however. (It's much easier to see certain trends on the bar-stack type display.)

Multi-Cylinder Model Basics

The EGT probe is located in each exhaust pipe, typically four to six inches away from the cylinder head. It measures the temperature of the exhaust gases exiting the cylinder. The actual temperature of the exhaust varies with a number of elements such as the power setting, altitude, ambient air temperature, and cylinder compression. It is also influenced by engine mechanical conditions such as ignition timing and cylinder leakage (compression loss), so you can see it's a very dynamic instrument with lots of diagnostic potential.

EGT even varies from combustion event to combustion event as the engine is running. (The thermocouple actually registers a kind of moving average: Exhaust gases are jetting past the probe in a pulsing manner, as the exhaust valve opens and closes.)

The EGT offers a peephole into this combustion process. Because it is so dynamic, the absolute numeric value of the EGT at any given moment is not as important compared to the moving average.

Also, it's the relative value of EGT (relative to other cylinders and relative to "normal" day-over-day performance) and the way that EGT responds to changes in the mixture control (i.e., changes in fuel-air ratio) that are of primary interest.

That said, absolute numbers can provide additional important information, but are somewhat secondary to the big picture provided by the bar stacks. Moreover, a barrage of varying digits can lead to sensory overload for the pilot.

In the very simplest sense, you can think of EGT as being a "rectal thermometer" for the engine. The single most fundamental piece of information any EGT system gives the pilot is the knowledge that combustion is occurring.

This is actually a very useful function, such as during an engine-out occurrence in a twin. An engine that's not producing power can still show rpm (and therefore oil pressure), manifold pressure (MP), fuel pressure, and oil temp. In fact, the MP of an engine that isn't running is the same as one that is at takeoff power (give or take an inch).

Just looking at the power gauges when one engine is surging (in a twin-engined plane) won't necessarily tell you which engine you're losing. Looking at the EGT will, because faltering combustion always shows up as dwindling EGT.

One of the best-known uses of EGT is to track fuel/air ratio (or mixture strength). When the pilot pulls the mixture control back, the F/A ratio decreases, and EGT begins to increase. As the F/A ratio continues to decrease, a point is reached when the EGT peaks and then starts back down.

This point of peak EGT is the reference point by which most pilots lean. It's the point at which the ratio of fuel to oxygen is chemically optimum for complete combustion (neither any leftover fuel, nor any leftover oxygen). The chemical name for this is stoichiometry.

CHT Indication

CHT is the residual heat from combustion and therefore ought (in theory) to be able to provide much of the same diagnostic information that EGT can. The main problem with CHT is that it is slow to respond. It also measures the temperature of one spot on the cylinder head, and nowhere else.

CHT can typically be taken from a probe in a threaded boss in each cylinder or from a special, wired gasket under a spark plug. The threaded boss is the more desirable option, and any mixing of temperature probe types can lead to pilot confusion, since the two probe types do not track each other closer than 30-60 degrees F or so.

Cylinder-barrel temperature can be and often is quite different from probe-indicated CHT. In contrast, EGT is much quicker to change, and the changes are larger in magnitude. This makes EGT a much more valuable tool for looking at irregularities in the combustion process. The two elements of EGT/CHT also have a symbiotic relationship in the sense that they help to confirm each other in a diagnostic sense. But CHT can be helpful alone for some diagnostic issues. Individual CHTs or banks can be dramatically affected by engine baffle issues/problems as well.

Common Indications

Some indications of trouble are shown in the example displays below. Bear in mind, the actual instrument indications may look somewhat different in real life, depending on ambient conditions, the cylinders affected, the type of engine, etc.

Also, one cannot always tell what exactly is wrong, because some malfunctions cause similar indications. Or there could be multiple malfunctions. But the key point is the simple fact that the display can show that something is wrong, and which cylinder is going astray places you far ahead of the minimally instrumented airplane. Moreover, with experience, you establish trends to help with diagnosing issues.

Probes sometimes give trouble, but generally are quite reliable. Some self-test. A temporary switching of probes can usually rule out a probe problem.

A common CHT differential is one or two bars among cylinders with proper baffles. Lycoming literature notes differentials of 100 degrees F or even 150 degrees F in carbureted engine, although we have not seen such divergence. We would do some serious baffle checking with such readings.

For EGT, it's commonly three to four bars or up to a 75-100 degree F temperature differential (hottest to coolest) in a fuel-injected engine. The EGT spread is the difference in fuel flow between the richest and leanest cylinders.

For a carbureted engine, the EGT differential can go to 150 degrees between the highest and lowest EGT -- possibly a bit higher for some poor induction designs such as the TCM O-470. Carbureted engine designs are simply less able to optimize the fuel flow to each cylinder.

In the case where aftermarket GAMIjectors are used in a fuel-injected engine, narrower and more beneficial inter-cylinder EGT spreads are obtained -- sometimes nearly perfect. (GAMIjectors are custom fuel injection nozzles designed to optimize the fuel flow to each cylinder based on extensive testing of examples of the representative engines done by the folks at General Aviation Modifications.)

Further note that this inter-cylinder EGT differential is not a fixed thing. It is dynamic in a given engine and will vary with the mixture and power settings (among other factors). At cruise power settings, generally the narrowest differentials for any given engine in good condition will be seen at wide-open throttle (most efficient), along with proper mixture management.

Aviation fuel injection is a very basic mechanical design (fuel is constantly sprayed at the back of the valve, not pulsed into the cylinder based on demand and timing). There are no feedback electronics (notwithstanding FADEC), so the pilot has to be knowledgeable to get the best available mixture from his system by proper leaning.

Example 1

The problem shown at right is a high EGT indication on cylinder #2 (numbering of cylinders is from left to right); CHT, however, is normal on all cylinders. The likely problem is that one spark plug has stopped working in #2 cylinder. If the EGT is intermittently high, the spark plug firing is intermittent as well.

Note: A single, high EGT reading could also be due to a partially obstructed fuel injector nozzle (in an injected engine). Spark plug fouling is more common, however. You can see the single-plug high EGT effect when switching to one mag at run-up: Watch the EGTs jump on one mag.

Example 2

In this instance, we are looking at a possible EGT bank-specific imbalance. The CHT indications are quite uniform.

In a fuel-injected airplane, the staggered EGTs with the seven bar spread of around 175 degrees shown here could mean the need for injector nozzle cleaning. In a carbureted engine, this kind of spread could be normal, indicating differences in cylinder compression and/or poor induction tuning between cylinders at the given power setting.

The bank-specific nature could be meaningful, however. More investigation should be made for the bank-specific EGT imbalance to see if there are any induction leaks/other causes.

Example 3

In this case, we're looking at a high CHT on #3 cylinder. The CHT is grossly, abnormally high.

Either there's some type of very abnormal combustion process going on in the cylinder (and certainly, pre-ignition should be considered with such a high CHT), or there is abnormally high friction in the cylinder, or the probe is being subjected to unusual heating.

Notice the low EGT on cylinder #5. An exhaust leak at the #5 exhaust gasket may be blow-torching the CHT probe on the adjacent cylinder (#3). If such torching is happening, a precautionary airport landing in called for.

It may be as simple as a bird's nest or other obstruction to cooling over #3 cylinder, but the cylinders 3 and 5 indications are abnormal enough to warrant a precautionary landing to see what's up.

Example 4

Notice the staggered CHT pattern on this gauge. One bank of cylinders is running colder than the other bank. A check should be made of cowling and engine compartment for cooling irregularities affecting one side of the engine. That includes checking the cowl flaps on cowlings that have two separate cowl flaps.

According to Insight Instrument Corporation, "On some aircraft, one inch of cowl flap misalignment will cause a 50-degree F difference in CHT." (See the Graphic Engine Monitor Pilot's Guide.)

Additionally, if this was a fuel-injected engine, such an EGT spread is pretty excessive (and still bank specific). Further troubleshooting is in order, including a nozzle and spark-plug cleaning to see if the spread cannot be narrowed.

Example 5

In this example, the EGT is low on #5 cylinder, as is CHT. The #5 cylinder is becoming a so-called "cold cylinder" through one cause or another.

Either compression is low, or fuel flow to the cylinder is so restricted that "the fire is going out." (If the engine is fuel-injected, it's time to look for significant nozzle blockage.) So check the nozzles and check compression.

Example 6

This time the #3 cylinder is indicating high EGT and CHT. The correlation of the two together can be taken as pointing to a combustion problem. (However, typically, preignition results in dropping EGT and rising CHT, and can be caused by something as basic as a faulty spark plug.)

Upon seeing this indication, the whole stack may be maxed out by the excessive CHT reading and the stack could be flashing or other pilot-set alarm going off. Reduce power and enrichen the mixture if possible, and observe for immediate lowering of EGT followed by CHT dropping off.

A precautionary landing and investigation should be made any time such divergent readings occur. In any event, upon landing, both spark plugs for #3 cylinder should be pulled and examined. Possibly a compression test and borescope examination should be done as well, but the cause must be found.

Example 7

Finally, this example should cause a certain amount of worry for any Lycoming owner. Notice the low EGT (and CHT) indications for cylinders #1 and #2. This could just be a normal indication for this particular engine. But it could also spell problems in those two cylinders.

One possibility is a bad intake lobe on the camshaft. The intake lobes (unlike the exhaust lobes) do "double duty" in that one lobe works the intake lifters for both opposing cylinders. Hence, cylinders #1 and #2 (on opposite sides of the engine) get intake-valve actuation from the same cam lobe.

When this lobe -- which is quite often the first one to go bad on a Lycoming cam -- begins to wear flat, the reduced duration and lift on the intake valve will begin to show up as reduced power and lower EGT, indicating an overly rich mixture. (Compression may be fine.)

We'll have more diagnostics with the engine monitor in upcoming articles in Light Plane Maintenance. If you would like to learn much more on mixture and general engine management, go to Advanced Pilot Seminars" for on-line and resident seminars.

More aircraft repair and prevention articles are available in AVweb's Maintenance Index. And for monthly articles about aircraft maintenance, subscribe to AVweb's sister publication, Light Plane Maintenance.

// -->

AVweb Insider Blog: Thielert's Recovery — Call Us Skeptical

Thielert's insolvency master says it has found investors for the troubled diesel engine maker. AVweb Editorial Director Paul Bertorelli doesn't see how they find value in the company, and that's the subject of his latest post to the AVweb Insider Blog.

Read more.

Diamond Aircraft Distributors Offer Tax Advantage Program
September 30th is the deadline to take advantage of up to $300,000 in depreciation opportunities on a new Diamond DA40 XLS. Diamond Aircraft distributors are also offering a $3,000 cash back incentive, to pay for the tax and legal services needed to take advantage of this tax savings opportunity. Go online for full details!
The Top Reporter on Our Crack Staff ... Is You! back to top 

Help AVwebBiz Spread Your NBAA News

The world's most important business aviation event, the National Business Aviation Association's annual convention, is coming up Oct. 6-8 in Orlando and there will be hundreds of product announcements and updates. AVweb will be there with daily coverage of the events, news conferences and announcements that make this show so important but if your company has something more than 100,000 business aviation decision-makers need to know about, we're encouraging you to let us know in advance. That way we can give your news the full attention it deserves and make sure it's released in a timely fashion during our coverage. Don't worry. We'll strictly observe all embargos. Send your advance material to rniles@avweb.com and thanks for your help in making our coverage the most comprehensive available.

AVweb's Newstips Address ...

Our best stories start with you. If you've heard something 200,000 pilots might want to know about, tell us. Submit news tips via email to newstips@avweb.com. You're a part of our team ... often, the best part.

Q: What's the Difference Between a $10,000 Annual and a $2,500 Annual?

Mike Busch and his team of seasoned maintenance professionals are saving their aircraft-owner clients thousands of dollars a year in parts and labor — not to mention hours of hassle — by providing professional maintenance management for owner-flown singles and twins. Learn how they do it.
Your Favorite FBOs back to top 

FBO of the Week: Galaxy Aviation (KSUA, Stuart, Florida)

Nominate an FBO | Rules | Tips | Questions | Winning FBOs

AVweb's "FBO of the Week" ribbon goes to Galaxy Aviation at KSUA in Stuart, Florida.

AVweb reader Adam Green recommended the FBO:

Enroute VFR and had to divert to Stuart due to weather. Galaxy's line guys were ready to greet us, and promptly helped us out of our Cessna and refueled. Inside, Vanessa and team were as friendly as can be and offered my girlfriend and Milo (the dog) coffee, popcorn, and dog treats. ... They even loaned us a car with a GPS, and gave us a list of local restaurants with directions so we could run out and grab a bite to eat. When we returned, we had a few hours to kill and their HD Satellite televisions in every corner were great entertainment. We even moved into the pilot's lounge where they offered us pillows and blankets, and gave us fresh popcorn to munch on. Thanks, Galaxy; this was a great FBO experience. Can't wait to come back!

Keep those nominations coming. For complete contest rules, click here.

AVweb is actively seeking out the best FBOs in the country and another one, submitted by you, will be spotlighted here next Monday!

Attention, Turboprop Operators! Reserve October 28-30 on Your Calendars
Turboprop Expo 2008, October 28-30 in Scottsdale, AZ, will offer specialized programs including seminar tracks for airframe and turboprop engine topics as well as operational and ownership information. Dr. David Strahle will present his informative and acclaimed seminar: Understanding Nexrad Imagery. Enjoy the relaxing surroundings of a classic resort and network with industry leaders at Turboprop Expo 2008. For more information and to register, visit online.
Reader-Submitted Photos back to top 

Picture of the Week: AVweb's Flying Photography Showcase

Submit a Photo | Rules | Tips | Questions | Past Winners

Each week, we go through dozens (and sometimes hundreds) of reader-submitted photos and pick the very best to share with you on Thursday mornings. The top photos are featured on AVweb's home page, and one photo that stands above the others is awarded an AVweb baseball cap as our "Picture of the Week." Want to see your photo on AVweb.com? Click here to submit it to our weekly contest.


It's time again to hold our submission bag upside-down and shake out all the exciting, unusual, and downright keen photos that came in over the last seven days so we can share them with the world.

medium | large

copyright © Gary Dikkers
Used with permission

Over the Top

Gary Dikkers of Madison, Wisconsin takes some pretty incredible photos as a matter of course — but it's been quite a while since he's found himself at the top of our submission pile, and it's probably time Gary got a new AVweb cap. (We're not 100% sure, but we think the design has changed twice since Gary earned the top spot a copule of years ago.)

Featured here, of course, are the amazing AeroShell Aerobatic Team thrilling the crowd at EAA AirVenture Oshkosh.

medium | large

Used with permission of Gini Shilt

Sun's Out — Let's Fly

Another name we're starting to recognize from the submission box is Gini Shilt of El Dorado Springs, Missouri. Given Gini's location, we're pretty certain those are the remnants of Hurricane Ike soaking the floor of the hangar ... .

medium | large

Used with permission of Bill Ryan

By the Light of the Silvery Moon? Not Quite ...

What at first seems to be an eerie glow can be seen for what it is in the full-size version of this photo — namely, dew highlighted by the searing flash of Bill Ryan's camera in an otherwise dark environment. (Bill joins us this week from Middletown, Maryland, by the way.)

medium | large

Used with permission of George Perks

C3B Stearman Over New York

Celebrating the 90th anniversary of U.S. AirMail, George Perks of Spokane, Washington treats us to this incredible view of New York City.

medium | large

copyright © Kerry Sim
Used with permission

Alan Snowie's 7:8 Scale Nieuport Over Bellingham Bay, Washington

Another Washingtonian, Kerry Sim of Blaine, flies us out this week against a serene backdrop. The shot, Kerry tells us, was taken from a Bellanca Scout flown by Merrill Wien. "He's colder than he looks," Kerry writes, confirming at least one of our suspicions about this photo ... .

You'll find more reader-submitted photos in the slideshow on AVweb's home page. Don't miss 'em!

Click here to submit your own photos to "POTW."

A quick note for submitters: If you've got several photos that you feel are "POTW" material, your best bet is to submit them one-a-week! That gives your photos a greater chance of seeing print on AVweb, and it makes the selection process a little easier on us, too. ;)

A Reminder About Copyrights:
Please take a moment to consider the source of your image before submitting to our "Picture of the Week" contest. If you did not take the photo yourself, ask yourself if you are indeed authorized to release publication rights to AVweb. If you're uncertain, consult the POTW Rules or or send us an e-mail.

No Cute Cartoons, No Fancy Covers, IFR Magazine Brings You the Facts
IFR magazine has insightful facts to polish your proficiency, updates on changing regs, and articles that help keep your decision-making skills sharp in the demanding IFR environment. Order your subscription online for savings from the regular rate.
More AVweb for Your Inbox back to top 

AVwebBiz: AVweb's Business Aviation Newsletter

HAVE YOU SIGNED UP yet for AVweb's NO-COST weekly business aviation newsletter, AVwebBiz? Reporting on breaking news, Business AVflash focuses on the companies, the products and the industry leaders that make headlines in the business aviation industry. Business AVflash is a must read. Sign up today at http://www.avweb.com/profile/.

Names Behind the News back to top 

Meet the AVwebFlash Team

AVwebFlash is a weekly summary of the latest news, articles, products, features, and events featured on AVweb, the internet's aviation magazine and news service.

The AVwebFlash team is:

Timothy Cole

Editorial Director, Aviation Publications
Paul Bertorelli

Russ Niles

Contributing Editors
Mary Grady
Glenn Pew

Features Editor
Kevin Lane-Cummings

Scott Simmons

Mariano Rosales
Jeff van West

Click here to send a letter to the editor. (Please let us know if your letter is not intended for publication.)

Comments or questions about the news should be sent here.

Have a product or service to advertise on AVweb? A question on marketing? Send it to AVweb's sales team.

If you're having trouble reading this newsletter in its HTML-rich format (or if you'd prefer a lighter, simpler format for your PDA or handheld device), there's also a text-only version of AVwebFlash. For complete instructions on making the switch, click here.

Aviate. Navigate. Communicate.