Rules of Thumb You Should Know

1) 10% Weight Increase = 20% Increase in Takeoff and Landing Distance

While this rule is far from exact, it gets you in the ball park for a normally aspirated plane.

Obviously, when it comes time to calculate your actual performance, you’ll want to pull out your POH.

2) Estimating a Crosswind Component

There’s an easy way to calculate the crosswind component.  If the wind is 30 degrees off the runway, your crosswind component is about 50% of the wind speed.

If the wind is 45 degrees off the runway, the crosswind component is about 75% of the wind speed.

And if the wind is 60 degrees or more off the runway, the crosswind component is roughly the same as the total wind speed.

3) Takeoff roll increases about 10% for every additional 1,000 feet of density altitude

For most normally-aspirated airplanes, you can add about 10% to the takeoff roll distance for every 1,000′ increase in density altitude (DA).

For example, in Denver, with an increase of 3,200′ of density altitude, you’d increase your takeoff roll by about 32%.

So if you have a 1,500′ takeoff roll on a standard day in Denver (3o C or 37o F), you’ll increase the takeoff roll to almost 2,000′ on a 30o C (86o F) day.

4) When Should You Start Your Descent from Cruise Altitude to Pattern Altitude?

A three degree glide angle will give you a comfortable descent rate in just about any aircraft. A three degree descent equates to a gradient of 318 feet per nautical mile. Unfortunately, 318 is not a mathematically friendly number, so we’ll just use 300.

When you’re approaching an airport, you simply plan your descent point:

Divide the altitude you want to lose by 300.

For example, if you’re at 11,500 feet, and you need to get down to a pattern altitude of 2,500 feet, you need to descend 9,000 feet.

9,000/300 = 30 miles.

If you start a 3 degree descent when you are 30 miles out, you’ll hit pattern altitude as you reach the airport. You’ll want to be at pattern altitude four to five miles before reaching the airport, so let’s start down at  35 miles.

5) Descent Rate from Cruise Altitude to Pattern Altitude

You’ve started your descent at 30 miles (see #4). But, how do you know if you’re descending towards the airport on a 3o glide path? Easy peasy! Simply multiply your ground speed by 5. For instance, if you are descending at a ground speed of 150 knots, for a 3o glide path, you should have a rate of descent of 750 FPM.

 6) Approach Descent Rate

What a coincidence! It turns out that a comfortable descent angle for landing just happens to be 3 degrees. In fact, most ILS and VASI/PAPI glide slopes are set for a 3 degree glide slope.

Check your ground speed on final and multiply it by 5. This will give you a target feet per minute descent rate. For instance, if your ground speed is 80 knots, you should be descending at about 400 feet per minute.

 Conclusion

You don’t need to have Einstein’s intellect to realize that rules of thumb are not meant to replace performance charts or good judgment. They can, however, help pilots understand the influences of different performance factors on their aircraft, and perhaps save a life or an ego. Whether helping you arrive at pattern altitude at just the right point, or preventing the continuation of a takeoff that could have gone awry, rules of thumb can be excellent additions to a pilot’s mental flight bag.

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Mag Checks and More

One of the readers of The Mooney Flyer wrote: I remember my instructor, an ex WW II pilot, giving me instructions on how to test the magnetos.  He advocated testing the magnetos in flight.  His premise was that in flight, the magnetos are under greater stresses and loads than they are during a run up.  If there were problems developing with the magnetos it would show up at that time rather than when they are lightly loaded.

REPLY: Frank Setzler, owner of Chandler Aviation, Inc. Chandler, AZ (a Mooney Service Center), agrees with Rich and his instructor from long ago. That’s because, when checking mags, it’s all about the pressure, stress and loads.

If you have an engine analyzer, you should watch the exhaust gas temperatures (EGT’s) to ensure that they rise about 50 degrees when the L and R mags are checked, compared to when the switch is in the “both” position.  With an even increase of all cylinder EGT’s, you can assume the magnetos are working internally at peak efficiency.

Pre-departure mag checks (Run-up)

These are more effective if they are checked under pressure by using a higher power setting (at least 15” of manifold pressure – or an RPM above 2,000).  Look at your individual EGT temps to verify that all injectors are firing properly by observing that all EGT’s are reading approximately the same.  One clogged injector reduces more than one cylinder worth of power!  Often times the operator must lean aggressively to keep from flooding the remaining good injectors with too much fuel.   Many “bad mag checks” can be caused by spark plug problems. A faulty spark plug affects the EGT drop on just one cylinder and one EGT bar. A faulty mag affects all EGT bars.

After the flight mag check

A high percentage of mag failures occur in flight. Prior to engine shutdown during taxi back, it’s a good idea to check that both mags are operating. Do this by selecting R/BOTH, then L/BOTH, while observing a slight drop in RPM.  There is no need to heat the engine up to run-up RPM’s at this point.  If you want to be on the safe side, Frank’s shop will always verify that when the MAG switch is in the OFF position, that indeed the engine will start to spool down.  This is only done at idle RPM.  To prevent backfire, it’s important to SLOWLY turn the key back to “R” from the OFF position.  You will notice the engine RPM coming back to life again, then “L”, and then back to “BOTH”.  If at any time the IGN Key can be removed from the mag switch in any position other then OFF, this is an unsafe condition and the IGN switch must be replaced.

Cruise

Frank has observed engines running rough or with a slight miss at high power settings; often at high altitude.  If the normal engine controls don’t help the engine run smoother, try a mag check in the air.  If you find that by going to the L and R mags, that the engine performance improves, then there is an internal problem with the mag that is OFF.  Fix that mag problem when you get back on the ground!  NOW.  It won’t get any better.

After Shutdown

Frank also recommends that owners add one more post flight task – drain the Gascolator and both wing tank sumps. This will get the water and debris out of the system so it doesn’t remain in the tank or Gascolator for an extended time. Water and debris can cause corrosion issues that Frank often sees with inactive aircraft.

Fuel Starvation – What can we learn?

On March 18, 2016, just before 3:30 pm, two teens were returning from a Nashville, TN Spring Break trip, when their rental Mooney M20C Ranger experienced engine failure. The pilot crash landed near the 14th hole of Wichita’s Tallgrass Country Club Golf Course. Both the pilot and his girlfriend sustained minor injuries.

The 17 year old Private Pilot had two years of experience. He reported that he conducted a preflight inspection of the airplane and noted that both fuel tanks were “filled to the rim.” (The M20C holds 52 gallons of usable fuel, 26 in each tank). They departed Dickson, Tennessee (M02), and headed for the rental Mooney’s home, Wichita’s Col. James Jabara Airport (KAAO), This was at least a 481nm flight.

AN EXTENDED DOWNWIND

The pilot extended the downwind leg, due to inbound instrument flight rules (IFR) traffic. On that extended downwind, the engine suddenly lost power. The pilot reported that he used the ALARMS checklist, Airspeed, Landing site, Air restart, Radios, Mayday, Secure plane, as he prepared for an off field landing. The Mooney flew over the top of some houses lining the Tallgrass 14th hole, then clipped a tree before striking the ground.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

NTSB EXAMINATION

An examination of the wreckage revealed no preimpact mechanical anomalies. The fuel tank selector was positioned to the left fuel tank, and the electric fuel pump was in the “OFF” position.

No fuel was found in the left tank. There was no smell of fuel, no evidence of fuel spillage, and the fuel tank did not appear to have been breached.

Some fuel, about 2 to 3 inches deep, was found in the right fuel tank.

If the pilot had switched the fuel selector from the left to the right fuel tank and turned on the electric fuel pump, the engine would not have been starved of fuel.

PROBABLE CAUSE
The National Transportation Safety Board determines the probable cause(s) of this accident as follows:

  • The total loss of engine power due to fuel starvation, which resulted from the pilot’s improper fuel management.

WHAT CAN WE LEARN?

GUMPS

As they approached James Jabara, a simple GUMPS check might have saved them from this accident. First on this check is “Gas”.

 STUPID FUEL GAUGES

Fuel gauges are notoriously inaccurate. In fact, the FAA requires that fuel gauges only need to be accurate one time. Yup! They must read “zero” when the fuel remaining equals the unusable fuel. Every other indication is the fuel gauge’s best guess.

GOOD FUEL MANAGEMENT

Because we can’t rely on our gauges, we really need to know our airplane and what’s happening in our fuel tanks. For instance, we should know how much fuel our aircraft burns the 1st hour, the 2nd hour, etc. With that knowledge, we can keep a good fuel record on our knee board. We’ll then know how much fuel is in each tank. If you’re keeping a good fuel record, you’ll know which tank has the most fuel for the approach and landing.

If you haven’t been keeping track of your tank quantities, then when an engine fails, the first thing to come into your mind should be, “Oh (insert your own choice word(s)! I let a tank run dry!”

THEN . . . Switch tanks. That’s the first item on most Engine Power Loss Checklists. The next steps are:

  • Mags – BOTH
  • Throttle, Prop and Mixture – FULL FORWARD
  • Boost Pump – ON

If those steps fail to restore power, you have no choice but to fly the aircraft all the way to the crash site.

Fly Safe, Jim

 

Check Your ADS-B Installation

The FAA is targeting non-performing ADS-B equipment that transmits incorrect flight identification codes and erroneous position reports, among other false data.

The FAA has provided a service that allows operators to verify the proper functionality of ADS-B equipment by sending a Public ADS-B Performance Report (PAPR) request. This request can be filed using a specific date from a flight along with ADS-B equipment information here. You can also verify that the Mode S code for your aircraft is correct by searching the FAA database here.

Fly Safe,

Jim

A MOSt Excellent Forecast Tool

MOS stands for Model Output Statistics.  A MOS forecast is derived from the output of weather prediction models developed and run by research meteorologists at NOAA. It determines the statistical relationship between that which is to be predicted and variables forecast by a numerical model at a particular time projection. The use of MOS has actually been around for decades, (since the 1970s) but has only recently been introduced for aviation use. ForeFlight included the MOS imagery in December, 2014.

When planning a flight, the FAA does not recognize MOS as a valid forecast. For instance, you must use the TAF (Terminal Area Forecast) when  you are determining if you will need an alternate airport.

ForeFlight contains MOS imagery in their “Imagery” section, listed under “GFS MOS” (Global Forecast System).

MOS ceiling imagery is depicted from 6 hours and every 3 hours through 84 hours.

MOS imagery is also available for Visibility.

Below is a ForeFlight MOS Ceiling image.

At the bottom of the image, you’ll see the legend. The lighter the green, the higher the ceiling predicted. The browns and yellows indicated ceilings that would not be appropriate for a VFR flight. Dark green indicates possible marginal VFR.

If you don’t have an iOS device, no problem!

FREE and Valid Weather Briefings

You can use Fltplan.com. It’s free and it has a good selection of weather imagery, but lacks the MOS imagery. If you are logged into Fltplan.com and receive their weather briefing, the FAA will consider your briefing valid, as if you had logged into flight service’s website 100wxbrief.com or called flight service for a weather briefing. The same is true if you receive a weather briefing using ForeFlight. In fact, ForeFlight gets your weather briefing from Flight Service.

FREE NOAA MOS Images

You can also see the MOS images at NOAA’s website. Just use the following URL: http://www.nws.noaa.gov/mdl/forecast/graphics/MAV/

 

 

 

 

 

 

 

 

 

 

 

 

The “Ceiling Height/Sky Cover” option has a drop down menu.

 

 

 

I’ve selected the first drop down menu option, “Ceiling Height (Cat)”, shown below. Times are in Zulu.

“Ceiling Height (Cat)” is the same imagery that is displayed on ForeFlight.

As you can see in the drop down menu, NOAA provides many Probabililty (Prob) images that are not found at ForeFlight.

The next time you have a trip planned, as you approach 84 hours prior to your takeoff time, you can watch the ceiling forecast. You’ll have a good idea of the probability that you’ll need to find alternate transportation. It’s just another great tool in your pocket to help you fly safely and have a MOSt excellent adventure.

Jim

The Brasher Warning

In 1987, in an NTSB case entitled Administrator v. Brasher, Mr. Brasher (the pilot) contented that the controller who found his piloting skills unsafe, had failed to give him a “possible pilot deviation” notification. As a result, Mr Brasher contended that because of that omission, the FAA waived its right to impose any sanctions against Mr. Brasher. The Board held that “the pilot deviation notification provisions “prescribe a duty, . .   imposed on FAA employees and instituted, at least in part, for the benefit of pilots”.

Hence, we have what is called the Brasher Notification, or Brasher Warning. It’s something like your Miranda rights, as in, you have the right to know that the FAA is not happy with your flying skills.

When an air traffic controller determines that pilot actions affected the safety of operations, the controller must notify the flight crew as soon as operationally practical using the Brasher Notification phraseology:

(Aircraft identification) POSSIBLE PILOT DEVIATION, ADVISE YOU CONTACT (facility) AT (telephone number).

The “Brasher Notification,” or “Brasher Warning” is intended to provide the involved flight crew with an opportunity to make note of the occurrence and collect their thoughts for future coordination with Flight Standards regarding enforcement actions or operator training.

If you receive a Brasher call from ATC, there are some things to know.

  • There is no need to make the telephone call immediately. Take time to think.
  • Call an aviation attorney before you make the phone call to ATC.
  • Your call will almost certainly be recorded. The AIM specifies that such calls are recorded and since you have the AIM memorized, legally that is sufficient notice. There is no tone or announcement. You may ask if the call is being recorded and to speak on an unrecorded line instead. The request may or may not be honored.
  • Anything you say can be used as an admission in court against you. Be polite, but not prolific when speaking. It’s discourteous to not return a call, but nothing says you have to spill your guts.
    • “This is N1234X. I was asked by __________ to call you after I landed. Can you tell me why?”
    • “I’d rather not say anything about it right now.”
    • “I’d like an opportunity to hear the tapes before I say anything.” (Pilot’s Bill of Rights)

What happens when a Brasher Warning is not issued and out of the blue, a pilot receives a letter or call from an inspector? Sometimes an inspector will contact an airman about a flight that occurred weeks or months earlier that was, from the airman’s perspective, completely uneventful.

In this case, it may not be too late to file a NASA form. According to Advisory Circular 00-46E, the 10-day clock starts ticking from the violation date, “or date when the person became aware of or should have been aware of the violation.” If it is debatable whether the pilot should have been aware initially, an argument may be made that the pilot was not aware of any problem, until he or she was contacted (or ambushed) by the inspector, making the report timely. A late filed report will not prevent the FAA from imposing a certificate action or civil penalty, but even a late report is evidence of the airman’s constructive attitude that may prevent future violations. Therefore, filing a report, even if late, may still be advisable as long as the event was not done in the spirit of criminal activity or if an accident occurred as a result of the action.

Keep in mind that even if you hear from the FAA unexpectedly, you are entitled under the Pilot’s Bill of Rights to the air traffic data, such as recorded audio or radar data. Since you were not on notice at the time, you may have missed the opportunity to preserve your own data that could be useful in your defense, such as GPS tracks or GoPro footage. This makes it even more important that you exercise your right to review the FAA’s data.

In addition to considering a NASA filing and requesting ATC data, please, do not make any admissions. One pilot received a letter six months after the flight in question, and he had no memory of the flight since it seemed routine at the time. Since you may not even remember the flight, it is important not to speculate on what may have happened.

It may be encouraging to know that unintentional pilot deviations that are the result of issues such as minor mistakes or diminished skills are within the scope of the FAA’s Compliance Philosophy, which focuses on resolving these matters through education, training, or counseling. Nevertheless, it is wise to keep your rights in mind and seek legal advice early in the process.

Mr. Proactive

A pilot received a Brasher Warning and before the FAA contacted him, he proactively started to do something about it. The FAA Inspector called the pilot about a week later. The pilot was very “humble” about the matter and had already logged some remedial ground and flight training with a CFI. This proactive attitude impressed the inspector and he asked the pilot to send copies of those logbook entries containing the CFI training. Upon receipt of the logbook proof of training, the case was closed.

The Value of Wings Participation

If you are a FAA’s WINGS Program participant, and find yourself are in “trouble” with the FAA, inspectors look upon your WINGS participation quite favorably. Man, you’re a righteous dude!

Legal Advice

You can join AOPA and sign up for their Legal Plan. If an Inspector calls and you say, “I will need to consult with my attorney”, that’s not looked upon as being uncooperative. No, it’s just smart.

Remedial Training

If you are offered a plan wherein you receive some remedial training from a CFI, and you refuse to participate in that plan, then you will be looked upon as uncooperative and nothing good will come from this.

Know Before You Leap

I hope you never hear a Brasher Warning directed at you. But, if you do find yourself in trouble, protect and arm yourself with knowledge and good legal advice before you leap into a friendly conversation with the FAA.

FAA To Block Erroneous ADS-B Signals

 About 20% of all ADS-B out systems are installed incorrectly. To help owners identify incorrect installations, starting January 2, 2018, the FAA filter these aircraft from the system. The filter will catch ADS–B equipped aircraft that are broadcasting erroneous or improper information that could affect the safe provision of air traffic services. Any aircraft subject to the filter will not have its ADS–B information sent to an ATC facility nor will the aircraft be a client for Traffic Information Services (TIS-B). “Affected aircraft will continue to receive ATC services within radar coverage using secondary radar information.

For those aircraft transmitting erroneous information, the Public ADS-B Performance Report (PAPR) will search for the flight ID matching the entered U.S. registry number if it cannot locate the corresponding mode-S code. The FAA could also use the filter for aircraft that are discovered to have other issues, including transmitting non-compliant codes, that could reasonably result in erroneous ADS–B information affecting the safety of ATC services.

The FAA intends when possible, to provide individual notice to owners/operators before implementing the filter. This notification would describe the reason for applying the filter and steps that must be taken before an aircraft can be removed from the filter. If an aircraft owner/operator does not respond to an FAA notice of finding regarding an ADS–B avionics issue, the agency might subject that aircraft to the filter without further notice. Owners and operators can identify the ICAO address filtering status of their aircraft by requesting a Public ADS-B Performance Reports (PAPR). This is available for aircraft operations within FAA ADS-B coverage areas. To use the tool, aircraft owners or operators simply input some basic information about a particular aircraft, including tail number, ADS-B equipment make/model and flight date. The FAA then sends the PAPR to the user’s provided email address, typically within 30 minutes. Users should understand that operations close to ground level or near the fringes of ADS-B coverage areas might not yield accurate results.

If the report includes an error message, the aircraft owner or operator can use that information to have the problem rectified by their avionics shop.

All aircraft operators with ADS-B equipment installed in their aircraft should take a few moments to use the PAPR tool. It’s critical that aircraft owners and operators verify the health of their ADS-B equipment and ensure the FAA is receiving accurate data. To request a PAPR, go to https://adsbperformance.faa.gov/PAPRRequest.aspx