Well had the second crash in a short period of time down here where I keep my plane. We have the cheapest fuel around and are real close to Destin, FL so we see a fair amount of tourists in and out of the area. The strip is 3700' paved in good condition and the field sits at ~80'. Most people don't even take DA into consideration until they notice they aren't quite getting the performance they expect, but 99% of time they slowly climb out and continue on their journey. DA is usually in the range of 2500'-3000' in midday into evening, so it can be a bit surprising to those who fill up.

This aircraft had 6 passengers (adults) who felt there was no need to check W&B or T/O performance for their high performance aircraft. A friend was there and witnessed the accident. He said they lifted off a little way past half way down. It came off the ground and then settled hitting the left wing, then the right wing. At this point it was past the end of the runway and went into the weeds. Luckily there is a nice little road that ran perpendicular to their flight path and launched them into the air and they landed right in the fence where they came to rest. Oh and did I mention all 6 in the aircraft were CFI's? Luckily they all walked away unscathed, but I bet next time they take a close look at the performance. A title means nothing if you can't exercise a little common sense and follow the rules.

There are places out west where those CFIs would never of lifted the nose wheel. Can get DA over 10,000' at some airports.

There are places out west where those CFIs would never of lifted the nose wheel. Can get DA over 10,000' at some airports.

At 80 ft MSL there is a tendency to get complacent about DA, but having spent my early years in the SouthEast and got my primary flight training there'; I can tell you a 90 degree day with 80% humidity can really degrade your performance at any altitude..

TD

TomD wrote:

There are places out west where those CFIs would never of lifted the nose wheel. Can get DA over 10,000' at some airports.

At 80 ft MSL there is a tendency to get complacent about DA, but having spent my early years in the SouthEast and got my primary flight training there'; I can tell you a 90 degree day with 80% humidity can really degrade your performance at any altitude..

TD

When I do my CIGAR check "A" = Altitude, Altimeter, and Area. DA can easily be forgotten.

I left the High Desert of Oregon (3) weeks ago at 5:30 PST and landed before 10:00, to take needed advantage of cooler temperatures. Floatplanes really need to be careful too.

Can anyone smarter than me educate us on the effects of humidity on fuel mixture. I live in Idaho(home airport at 4700ft). In the cold dry months around here I burn more fuel due to the extreme lack of moisture in the air(more pure air available, means more fuel needed). As I read this article I wondered if mixture had anything to do with this crash. DA is always a consideration on hot days but a engine running too rich or lean won't generate the needed power. Kind of like taking of with the carb heat on..........(ya I've done that).

180lamb wrote:Can anyone smarter than me educate us on the effects of humidity on fuel mixture. I live in Idaho(home airport at 4700ft). In the cold dry months around here I burn more fuel due to the extreme lack of moisture in the air(more pure air available, means more fuel needed). As I read this article I wondered if mixture had anything to do with this crash. DA is always a consideration on hot days but a engine running too rich or lean won't generate the needed power. Kind of like taking of with the carb heat on..........(ya I've done that).

I lean for power at sea level when the DA is high. That's kind of the point of the concept: Temperature has a huge effect on air density and it's not limited to just mountains and high desert. While I'm sure humidity plays a role, there aren't many easy ways to calculate its effect on how much more you have to lean for max power. How much air is available for combustion will be revealed when the mixture is adjusted for max power or RPM (with a fixed pitch prop.) The technique for doing that is probably the most important factor.

Lycoming issues an operating manual for each new engine (and a plethora of legacy engines). Also "service letters" for the operation are issued which should be kept by the operator which address subjects like oil, temperatures, turbos, fuel, leaning and extending published TBO etc.

I start by reading the factory operating manual of the engine(s) and amendments. Leaning at WOT may not be advisable with some engines until a very high DA.

There are CFI teaching a lot of witchcraft which conflicts with published numbers. I know Pilots that have never read the factory recommendations that are published, which are ruining engines.

6 fat CFIs and full fuel...not too many single engine piston aircraft gonna haul that well at any alt. I bet they were over gross.

littlewheelinback wrote:6 fat CFIs and full fuel...not too many single engine piston aircraft gonna haul that well at any alt. I bet they were over gross.

The NTSB will agree! I hope...

I can't find any charts, formulas, etc., but my late 70's Jeppeson commercial and CFI books state that 100% humidity can reduce max horsepower by "up to 12%", in addition to loss of power caused by altitude. I assume a hot day in Florida would be close to 100% humidity.

field 80' MSL, 3,700' long, DA 2,500'-3,000'.

littlewheelinback wrote:6 fat CFIs and full fuel...not too many single engine piston aircraft gonna haul that well at any alt. I bet they were over gross.

^^^this^^^ that's a stuffed Bonanza!

Did anyone see a tail number ? Just wondering what the TC published for GW.

The FAA has been known to blame the guy with the most ratings for anything bad that happens in flight. It will be interesting to see who gets lectured about what.... with 6 instructors in one plane. I believe they have the horsepower of one or maybe two... from the sounds of it.
Maybe some 709 check rides in their future.

Dale Moul wrote:I can't find any charts, formulas, etc., but my late 70's Jeppeson commercial and CFI books state that 100% humidity can reduce max horsepower by "up to 12%", in addition to loss of power caused by altitude. I assume a hot day in Florida would be close to 100% humidity.

My pitot-statics course just went over rebuilding all the standard day equations. They said that the changes in air between dry and wet (humidity) were negligible.

Dale Moul wrote:I can't find any charts, formulas, etc., but my late 70's Jeppeson commercial and CFI books state that 100% humidity can reduce max horsepower by "up to 12%", in addition to loss of power caused by altitude. I assume a hot day in Florida would be close to 100% humidity.

That 12% figure sounds a bit exaggerated. It's true that the error goes up with relative humidity, but even with 100% humidity, you're looking at more like a 3-5% error. It's worth noting that AWOS when it computes density altitude doesn't take humidity into account.

I fiddled around with DA formulas for a project a few years ago. A good (fairly technical) resource is this site:

http://wahiduddin.net/calc/density_altitude.htm

I leaned 0-320 Lycoming engines for every takeoff for over ten thousand hours and got over 3,000 hours between major overhauls on three engines. We ran them 25 hours per week and never make long climbs or descents on the pipeline. Carburetor fueled Lycomings like lots of fuel to start but don't idle, taxi, or run at any speed well until they are leaned.

They probably figured they were heavy but didn't fly like it (use low ground effect.) Even if we have done all the math, not flying like things are going to go wrong may cause us to not take advantage of all energy available. They did a good job flying all the way to the crash site. That is why they walked away.

Years ago before my pard and I bought the T210, we flew a number of different airplanes. The reason we chose the T210 over the A36 was simply useful load--the T210 is quite a load hauler compared to the A36. The A36 was a honey of an airplane, though, and during our test flight, I flew it with 6 full size guys aboard--but only half tanks. Accelerating to between Vx and Vy, it easily climbed out at Laramie on a cool Fall day--probably 55F, for a DA of about 8700'. Nothing wrong with an A36's performance, but like most airplanes, it won't tolerate overloading.

Cary

I have been close to that type of landing spot myself. If you can walk away you are lucky, if you learned something you are a better pilot. Go get a beer and figure out how to get the next plane.
DENNY

8GCBC wrote:

littlewheelinback wrote:6 fat CFIs and full fuel...not too many single engine piston aircraft gonna haul that well at any alt. I bet they were over gross.

The NTSB will agree! I hope...

Actually the NTSB didn't show up. they released the investigation to the MX FBO on the other side of the ramp. I would think it would be a conflict of interest as the owners of the different FBO's don't get along.

I forgot to mention that not only were there a shitload of people on board, but they also had baggage and full fuel.

N-Number is 636TM

Timberwolf wrote:

8GCBC wrote:

littlewheelinback wrote:6 fat CFIs and full fuel...not too many single engine piston aircraft gonna haul that well at any alt. I bet they were over gross.

The NTSB will agree! I hope...

Actually the NTSB didn't show up. they released the investigation to the MX FBO on the other side of the ramp. I would think it would be a conflict of interest as the owners of the different FBO's don't get along.

I forgot to mention that not only were there a shitload of people on board, but they also had baggage and full fuel.

N-Number is 636TM

Ummmm, FBOs don't conduct investigations of accidents. The NTSB may have turned over the investigation to the FAA in the form of the local Flight Standards office......

As to loading, bear in mind I have two good friends who are CFIs and their combined weight is less than 200 pounds. I know, not the average, but it might be a better idea to let the powers that be figure out the probable cause, rather than crucifying someone based on Internet babble.

Just saying....

MTV