Come out to Redbird Skyport at the San Marcos Municipal Airport on Saturday, May 30th for the Bluebonnet Fly-In. Hank Gibson from Texas Top Aviation will be giving a safety presentation at 2pm in the large conference room entitled “Is The Approach Activate? Flying Garmin Approaches.”
Join Texas Top Aviation and Redbird Skyport as we open the summer together at the Bluebonnet Fly-In.
To Register for the Safety Seminar, please click here.
Density Altitude: Pressure Altitude corrected for non-standard temperature.
That’s the book definition of density altitude. The problem is, that definition leaves a lot of general aviation pilots scratching their heads. What really is density altitude?
All airplane engines rely on air and fuel mixing together, then that mixture is ignited to create combustion. Normally aspirated piston engine airplanes get their best performance at sea level, where the air is nice and thick, allowing plenty of air molecules to get sucked in the engine intake. As a normally-aspirated airplane climbs, the ambient air pressure drops with an increase in altitude (the air gets thinner, less dense), thereby reducing airplane takeoff, climb, and landing performance. There just isn’t as much air at higher altitudes, to put it simply.
Turbo charged piston engines assist with this air density problem. A turbo charger boosts the air coming into the engine and fools the engine into thinking it is at sea level pressure all the time. The higher the altitude, the faster the turbo charger spins, spinning the compressor faster, which compresses more air to continue to give the engine sea level pressure air. This gets faster cruise speeds the higher you go.
Both normally aspirated & turbo charged engines do experience longer takeoff rolls and reduced climb rates at higher airport elevations & higher altitudes.
How does this all relate to density altitude?
When the outside air temperature rises, the air becomes thinner, less dense. This means that when an airport elevation is 1,000 feet, but the density altitude is reported as 3,000 feet, the airplane engine thinks it is at 3,000 feet. It won’t accelerate as fast. The airplane’s climb rate will also be reduced. That means that the normal climb pitch attitude a pilot is used to seeing won’t be accurate at higher density altitudes. It will lead to slower indicated airspeeds, slow enough to potentially lead to a stall if a pilot isn’t paying attention.
Where does this get dangerous? High elevation airports. Whenever the OAT creeps above 85 or 90 at an airport that is higher elevation (I would classify higher elevation as 2,500 feet or higher), the corresponding density altitude sky rockets. If a pilot isn’t paying attention to airspeed or angle of attack (if the airplane is equipped with an AOA), a stall can come very quickly on climb out.
What to take home from this? Monitor your climb speed and angle of attack, especially right after takeoff, when you hear density altitude on the ATIS or AWOS.
In July, a Cirrus SR22 suffered an engine failure in Houston after departing KIAH. The CAPS system was deployed and the airplane came to rest in a neighborhood on the north side of Houston. This makes CAPS save number 53 for Cirrus and no fatalities. The initial NTSB report is below.
14 CFR Part 91: General Aviation
Accident occurred Tuesday, July 07, 2015 in Houston, TX
Aircraft: CIRRUS DESIGN CORP SR22, registration: N422PB
Injuries: 2 Minor.
This is preliminary information, subject to change, and may contain errors. Any errors in this report will be corrected when the final report has been completed. NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.
On July 7, 2015, about 1137 central daylight time, a Cirrus SR-22 single-engine airplane, N422PB, descended under the canopy of the cirrus airframe parachute system (CAPS) and landed in a residential neighborhood at Houston, Texas. The pilot and passenger sustained minor injuries, and the airplane was substantially damaged. The airplane was registered to and operated by AIRCCS, LLC; Humble, Texas, as a 14 Code of Federal Regulations Part 91 business flight. Day visual meteorological conditions (VMC) prevailed and a flight plan had not been filed. The airplane departed George Bush Intercontinental/Houston Airport (IAH), Houston, Texas, at 1133 and was destined for Austin Bergstrom International Airport (AUS), Austin, Texas.
The pilot reported that during initial climb, he noticed the engine temperatures began increasing and he reduced power in an attempt to lower the engine temperatures. When the airplane was about 900 feet above ground level (agl) the engine began detonating, and soon after there was a complete loss of engine power. With no suitable forced landing areas the pilot deployed the CAPS ballistic parachute system and the airplane impacted terrain and came to rest upright next to a residence.
An initial on-scene wreckage examination showed there was adequate fuel on-board. At the facility where the airplane had most recently been refueled, refueling unit records and a review of security camera video showed that the airplane had been refueled with aviation gasoline and not with jet fuel. Postaccident fuel quality checks of that fuel facility were satisfactory.
The wreckage was moved to a different location and will be further examined. Several avionics components containing non-volatile memory (NVM), including engine performance data, will then be removed from the wreckage for examination and an extraction of useful data is expected.
At 1053 the Automated Surface Observation System at IAH reported wind from 160 degrees at 15 knots gusting to 20 knots, visibility 10 miles, scattered clouds at 3,000 feet agl, broken clouds at 25,000 feet agl, temperature 31 degrees Celsius (C), dew point 24 degrees C, and an altimeter setting of 30.03 inches of Mercury.
The AOPA Air Safety Institute is making it’s annual loop through Texas this January. The topic for this Safety Seminar is “More Difficult Decisions: Choices & Consequences.”
The seminar is geared our the decision making process that we as pilots face on each flight. Some decisions are easy (what altitude should I pick?) while some have much greater consequences and should be taken very seriously.
This event will be interactive for the participants as several scenarios will be presented. The goal is to help pilots learn to think through each decision, weighing the consequences along the weigh to arrive at the safest outcome of the flight.
The first area seminar will be held on Tuesday, January 21st at the Stinson Field Airport (KSSF, 8535 Mission Road, San Antonio, TX 78214). The second area seminar will be held on Wednesday, January 22nd at the TXDOT office in Austin (200 E. Riverside Dr., Austin, TX 78704). WINGs credit is available for all attendees.
Learn more here.
I began flying a Piper Malibu earlier this year. For those of you not familiar with the original PA-46, a Malibu has a Continental TSIO-320 engine, with 310 HP. It’s pressurized and cruises at about 185-200 KTAS.
A few things are introduced to the equation when pilots start flying higher, faster, and farther. When you start flying over longer distances, weather becomes more of an issue. On a quick hop from, say, Austin to Dallas, you can be pretty sure of what the weather will be since it’s a short trip. When you fly from Austin to LA, leave in the morning, land once along the way, and arrive in the afternoon after spending six and a half hours in the air, weather can change a lot in that amount of time.
A must for any pilot flying high and over long distances is some kind of Nexrad system, whether it be a Garmin 696, or it shows up on your GPS or MFD. Having this situation awareness is very helpful when planning ahead as to what to do about weather. A stormscope is also a handy tool, since you can see where the lightning is with it.
Cold fronts can be pretty nasty, depending on how strong and how fast they are moving. A strong, fast moving cold front usually has a lot of convective activity associated with it. The tricky thing with storms associated with fronts is that storms form in lines, most of the time. If you’re trying to cross a front in the morning, you can usually get high enough over the clouds with a pressurized airplane since the temperature is still relatively low to get clear of the cumulonimbus clouds. The cloud tops will only be around ten or twelve thousand feet.
Crossing fronts in the afternoon when daytime heating is pushing the tops of the CBs up to the 20-40 thousand foot range, it’s best to land, have a meal, stretch your legs, and wait till the sun starts to go down before pushing on. Do not, under any circumstances, try and go through the cumulonimbus clouds associated with a cold front in a small airplane. Not only is it uncomfortable (the turbulence bounces you around pretty good), but you’ll get ice, scare the passengers, and, if you’re in the heart of a storm, the plane could come apart.
When crossing mountains, the weather is always highly unpredictable. If it’s a clear day, no matter your altitude, you’ll probably pick up some turbulence from all the rising air off the peaks. If there is moisture in the air, there are going to be isolated to scattered thunderstorms in the summer time. The advantage of flying high when there are isolated or scattered storms is you can utilize the see and avoid method.
See and avoid is simple. When the storms aren’t embedded in other clouds, it’s actually rather easy to spot the big, rising clouds and go around them. The same concept holds true when avoiding those pesky pop up thunderstorms in humid areas like Houston and Florida.
One thing that I learned this summer was this. Sometimes, with an area of closely grouped storms, the cloud base is actually quite high (some storms I went underneath in New Mexico had cloud bases of 15,000 MSL). The thing to do here is just stay below the bases of the clouds and go around the areas of rain. These will be visible and you’ll be able to navigate around them. With bases even as low 9-10 thousand feet, it’s a much better idea to stay below the clouds, sacrifice some speed, and dodge the rain shafts.
The most important concept to take away is don’t fly into a thunderstorm. If there are a bunch of really high clouds in front of you and you don’t see a safe way around them, descend down and land, wait it out, and then continue on your way.
When I was working on my instrument rating back in 2007, my instructor and I did a lot of unpublished holds. In ground school, I heard a lot about holding for weather or holding due to a traffic delay. At my first job, my chief flight instructor was also a Continental (now United) captain and he told me a lot about having to hold for weather going into different places.
I heard all this, but I figured it would never happen to me when I’m flying GA airplanes.
Boy was I wrong!
I was flying a Piper Malibu into Phoenix with two passengers for Super Bowl weekend and the weather was awful. No thunderstorms, but moderate precipitation and low ceilings. We were coming into Deer Valley (KDVT) on the north side of Phoenix and about an hour out, ATC advised me that arrivals into DVT were having to hold and to expect a delay. The controller said the delay would be about 30 minutes, so by doing a quick calculation, I determined the delay would probably be all cleared up by the time I got in the area. At the time, I didn’t know if the delay was due to weather or traffic congestion.
Twenty minutes later, the controller advised me that there was still a delay. I queried what it was for and he informed me it was due to weather. He asked me if I wanted to hold or divert. I listened to the ATIS and heard the ceilings were variable from just below the minimums to just above. I told him I would hold as the TAF I saw predicted the ceilings to go up.
“Malibu, hold present position, hold east, expect further clearance 2140 Zulu.” Gulp.
At this point, my autopilot had gone out, it was turbulent and I was definitely in the soup. This was going to be fun.
After recovering my wits, I read back the clearance, then set about setting up this hold without getting too far from my present position. The Malibu I was flying had a Garmin 530 which I was using as my primary means of navigation. I was on V190, but I didn’t have all the fixes in my flight plan. What to do? And what to do fast?
The 530 has a rarely used function called a User Waypoint. It comes in handy in situations like these. On the moving map, you can turn the cursor on, move the cursor to any point on the map, and, by pressing enter, create a User Waypoint. This is what I did on V190. After I created it, I had to go to my flight plan, find the right spot, and input the User Waypoint just like I would any fix. Just a note here, when you create a User Waypoint, make sure you remember what you named it so you can find it again.
After I input the User Waypoint in the flight plan, I had to go back and activate the leg that the User Waypoint was the end point on. Then, to make sure the flight plan didn’t go to the next waypoint once I crossed my User Waypoint, I had to press the OBS button on the 530 in order to put the GPS in suspend mode.
Keep in mind, my autopilot wasn’t working, so this involved a lot of multi-tasking!
That’s how to do a present position hold using the Garmin 530. Got all that? Here’s a concise review:
There has always been something that felt wrong to me about how the walkway on many models of Beechcraft extends onto the right hand flap. I have never felt right about stepping onto the flap as I make my way into and out of my dad’s E33A Bonanza and therefore I generally try to step over top of it and place my foot on the wing instead. But does this effort actually make any difference, or am I just making my self look silly for no reason?
Well, as it turns out, it wasn’t such a bad idea. In 2007, a pilot flying a Beech reported a split flap condition. Upon inspection, it was found that there was damage to the actuation rod attachment as well as the nose rib and nut plates. Six other aircraft were checked and found to have similar damage. These findings were submitted to Hawker Beechcraft and in 2008 and they issued a maintenance alert regarding the issue. In 2011 the FAA issued SAIB CE-11-21 (Special Airworthiness Information Bulletin) to alert owners, operators, and maintenance personnel about the problem; specifically warning of the potential for cracking in the nose flap rib (part number 35-165050-84). And while its true that this type of damage is not limited to the right hand flap, it is known to be much more common on that side. Stepping over the flap instead of on it is recommended by both the FAA and Beechcraft as a solution.
Unfortunately, the flap cracking is known to span a wide variety of aircraft types. A 2011 “Safety Communique” issued by Hawker Beechcraft lists the affected models as:
-Bonanza 33, 35, and 36
-Baron 55, 56, 58, and 95
-Duke 60
According the the FAA, the cracking can been found most commonly on airframes which are between 4,000 and 6,500 hours, but has also been found on aircraft with as few as 2,000.
So, what do we do about it?
First off, although much of the damage is difficult to detect without dis-assembly, the paperwork from both the FAA and Beechcraft recommend taking a look at the flap yourself to see if there are any obvious signs of problems. They also suggest taking special care looking in this area during your preflight inspections.
Next, if you have an airplane which may be susceptible to cracking, talk to who ever is doing your maintenance work and have them look carefully during your annual inspections. I talked to one of the IA’s at our shop who has dealt with this issue before and he told me that most shops will remove the flap and send it away to a repair station to have it fixed. It’s possible that if you purchased your airplane used it may have already had this issue taken care of; a quick look through the maintenance logbooks should clear up any questions.
Regardless of whether your airplane is known to suffer from this problem or not, do your best to avoid stepping on the flap when getting in and out of the cockpit. It is also a good idea to ask your passengers to do the same as this simple act could end up saving you big headaches and big money someday down the road.
For more information regarding the flap issues discussed above, talk to your maintenance provider and visit these links:
ABS Flight Controls, Flaps, and Trim System Inspection, Repair and Rigging Guide (See Page 17)
ABS Information on SAIB CE-11-21
Andrew Robinson is a 135 Charter Pilot and flight instructor in Pennsylvania. He flies Pilatus PC-12s and instructs in Beechcraft Bonanzas.
