I owe my life to my CFI.

[Dean]

I am going to tell a story on myself that I am not proud of, but hopefully it might keep someone else out of trouble.

Yesterday the wife(Kelly) and I flew to 2K2 to spend the night and fly the son home on Friday. He has been with Oma and Pop for a few weeks. I wanted to leave before noon so the heat would not be to bad. At 11:30 we loaded and started out. I had done a weight check the night before and we were 1580 lbs, 20 lbs under gross.
The stripe at 2K2 is 2300' and has a 1.1% grade, wind was favoring 17 which is uphill. DA was at 2900' with a temp pushing 90. My normal rotation speed is 60 so I up it to 70 to allow for the high DA. Everything was going good and the climb out was about 300FPM. Suddenly I noticed the airspeed drop and the VS go to 0. Next thing the stall horn starts to chirp.
My first instinct was to pull the yoke back for altitude, thats when I heard my CFI saying, nose it over, level off and gain speed, then start climbing slow. I will have to say, I have never been so scared scenes I started flying. My wife did not say a word until we got home, that's when she said, how close where we to going down? I told her it was not that close, but one wrong move could have changed things in a hurry.
She replied, I told you we needed a bigger plane, u got to love her.
I hope this reminds everyone to go light as possible when its hot or don't go at all. Our outcome was good, but I have seen others that were not as lucky.

 

[Dave Krall CFII]

I am going to tell a story on myself that I am not proud of, but hopefully it might keep someone else out of trouble.

Yesterday the wife(Kelly) and I flew to 2K2 to spend the night and fly the son home on Friday. He has been with Oma and Pop for a few weeks. I wanted to leave before noon so the heat would not be to bad. At 11:30 we loaded and started out. I had done a weight check the night before and we were 1580 lbs, 20 lbs under gross.
The stripe at 2K2 is 2300' and has a 1.1% grade, wind was favoring 17 which is uphill. DA was at 2900' with a temp pushing 90. My normal rotation speed is 60 so I up it to 70 to allow for the high DA. Everything was going good and the climb out was about 300FPM. Suddenly I noticed the airspeed drop and the VS go to 0. Next thing the stall horn starts to chirp.
My first instinct was to pull the yoke back for altitude, thats when I heard my CFI saying, nose it over, level off and gain speed, then start climbing slow. I will have to say, I have never been so scared scenes I started flying. My wife did not say a word until we got home, that's when she said, how close where we to going down? I told her it was not that close, but one wrong move could have changed things in a hurry.
She replied, I told you we needed a bigger plane, u got to love her.
I hope this reminds everyone to go light as possible when its hot or don't go at all. Our outcome was good, but I have seen others that were not as lucky.

How many feet did you clear the obstacle by Dean ?

 

[Let'sgoflying!]

Appreciate the story, Dean.
Hey, how much wind? There has to be a decent wind to favor taking off uphill.
Also consider obstacles, was one way better than the other?
Every expert I have heard says do not compensate (add 10kts) to IAS for any maneuver in high DA situations, it is mostly compensated for already.
Did I miss what type? 1580 & three people - 150 with jump seat?

 

[bbchien]

thats when I heard my CFI saying, nose it over, level off and gain speed, then start climbing slow....
...She replied, I told you we needed a bigger plane, u got to love her.
I hope this reminds everyone to go light as possible when its hot or don't go at all. Our outcome was good, but I have seen others that were not as lucky.

Score one for stall awareness training.
Deano, TAKE HER UP ON IT. Start with something around 180 horsepower. There is no substitue for horsepower.

 

[Lawreston]

Appreciate the story, Dean.

Did I miss what type? 1580 & three people - 150 with jump seat?

My thoughts, precisely! Moving from a "172" to a "150" I've become super-sensitive to the variances. Good recovery, Dean. Now, I'll read the rest of the responses.

HR

 

[silver-eagle]

Nah... Go right on up to that 300hp Dakota or how about a new Cherokee 6?

Sorry, I'm dreaming again.

 

[mikea]

I'm glad it came out OK. Did you notice how you get quiet when things get hairy, so as not to scare the passengers? As Rod Machado says, we have learned how to sweat only on the left side of the face.

Even when you get more HP you can't forget the lesson.

I had a similar learning experience when I loaded up all 4 seats to take Mom and a cousin to PA for their first flying XC with me. It was the first time I was near gross and it was HOT HOT HOT.

I had that cocky attitude that I'd never need that 235 horsepower and the nearly 1400 pound useful load.

I had the foresight to roll out to the turf section of the runway to get the extra 1000 feet.

In my case it was simply that I wasn't seeing the usual enthusiastic climb. I pulled a little on the yoke and the stall light started blinking. Woah! It ain't got no mo. I eased back and took the 400-500FPM climb it had vs. the usual >1000FPM.

That's why we get drilled on departure stalls, huh?

That was a learning experience I never forgot.

 

[Greg Bockelman]

Appreciate the story, Dean.

Did I miss what type? 1580 & three people - 150 with jump seat?

Yeah, It was. I saw it at Gaston's.

 

[AdamZ]

Whew! Every lesson makes us better pilots thanks for sharing it with us.

 

[woodstock]

had the stall horn go off on me on departure for the first time Tuesday. HOTTEST DAY IN TWO YEARS and my friend in the back seat for this flight. boy did we climb like a pig.

even 172s seem to be 4 seaters in name only. the backseats are about as useful as those in convertibles.

 

[poadeleted20]

Every expert I have heard says do not compensate (add 10kts) to IAS for any maneuver in high DA situations, it is mostly compensated for already.

While you shouldn't blindly add IAS for high DA, most light airplanes' short field procedures call for rotation at a higher IAS than for a "normal" takeoff. This allows you to accelerate a bit faster before rotating straight to the Vx attitude, usually at about Vx-5 or so. The "normal" rotation usually is at a lower speed allowing a smoother takeoff albeit one that takes more runway.

However, the rotation for best short-field performance does change with increasing DA since Vx goes up as DA goes up. Flying out of RKS with a 10K DA (6800 elev, 75F OAT) two weeks ago, I held the nose down until 70 KIAS in the Tiger to get best takeoff performance, since Vx and Vy were probably close to merging at about 80 KIAS in those conditions. That said, 3000 feet DA isn't going to change Vx on a light single by more than a couple-three knots.

In any event, read the book, learn the book, fly the book.

 

[fgcason]

My normal rotation speed is 60 so I up it to 70 to allow for the high DA.

Why do that? That just makes you go even faster (end of runway sooner) and likely puts you further away from Vx/Vy. Airspeed indicator is ram air pressure. Reduce the molecules (higher DA) and you have a higher TAS for the same ram air pressure (IAS) ... then you added 10 kts to that.

I fly basically the same climbout and approach indicated airspeeds (based on what the correct numbers are) up here at 6183+ MSL as I do at SL even when the DA is 10,000ft. I am fairly notorious at lifting off when able then accelerating in ground effect to Vx/Vy before starting the climb since I grew up on a short soft field. TAS is higher to start with by about +12 kts so everything is moving faster in relation to the ground but the ground is not important. Add another 10 kts to that regardless of DA and you float closer to the end of the earth on landing and climbout becomes, shall we say, exciting.

Everything was going good and the climb out was about 300FPM. Suddenly I noticed the airspeed drop and the VS go to 0.

Turbulence? Shear? Downdraft? Nose up subconciously? Why did it slow down?

thats when I heard my CFI saying, nose it over, level off and gain speed, then start climbing slow. I will have to say, I have never been so scared scenes I started flying.

Yep. My Aunt had the same thing going through her head one afternoon when she got tossed around, bounced off the runway and ended up going uphill above the trees with the airspeed dropping. Trees are below, rising terrain but the nose HAD to go down NOW so she did. Had she not done that, she would have certainly ended up in the treetops. Turned out ok except for the dinged prop from the runway hit.


High DA: Everyone around here that I've talked to recommends at least 10% under gross, as much HP as you can get and fly when the DA is lower.

 

[Jeff Oslick]

The mistake most pilots seem to make on climbing out under higher DA is to rotate to the same pitch attitude they are used to for their normal DA condition. I suspect this is what happened to you - even though you rotated at a higher speed, you pulled back to too high a pitch attitude and bled off all that extra airspeed and then some more, resulting in the near-stall.

This is a fairly common problem for LA Basin (near sea level) pilots flying up to Big Bear, only a few dozen miles northeast of LA, but at 6,700 MSL. Inexperienced pilots don't think enough about what the difference in DA will really mean for how to fly the plane. That is exactly why every FBO I can think of in LA requires any rental pilot to fly with an instructor to Big Bear the first time they go.

All that being said, if the better half is blessing it, and you can $wing it, buy a bigger plane (182s are nice...but maybe I'm biased... )

Jeff

 

[Eamon]

Humm reminds me of taking off from Hooterville... (Hendersonville, NC)

I had me Ex & my three kids on the Mouse...............

All I could think was power lines, Trees, Mountain, Or dive & crash.........

Choices, Choices................

Now with the 182.... No Problem................

M~M

 

[wsuffa]

Dean,

Glad you learned & remembered the stall awareness lesson. Take a look at my replies to Dave Taylor in the other string about the crash near Junction this week. What are the book numbers for takeoff and clearance distances for that DA and weight?

You have a very supporting spouse. There is NO substitute for power.

bill

 

[Eamon]

Dean,

Glad you learned & remembered the stall awareness lesson. Take a look at my replies to Dave Taylor in the other string about the crash near Junction this week. What are the book numbers for takeoff and clearance distances for that DA and weight?

You have a very supporting spouse. There is NO substitute for power.

bill

NO substitute for horsepower you mean...............




Oh that might be mean..........

 

[poadeleted3]

had the stall horn go off on me on departure for the first time Tuesday. HOTTEST DAY IN TWO YEARS and my friend in the back seat for this flight. boy did we climb like a pig.

even 172s seem to be 4 seaters in name only. the backseats are about as useful as those in convertibles.

The 172R model I think I remember you said you flew is a heavy plane, without a whole bunch of useful load. They are intended mostly as trainers with two aboard.

 

[Dean]

How many feet did you clear the obstacle by Dean ?

Going south it is pretty much open, a few trees, cleared them by 200'+

 

[Dean]

Score one for stall awareness training.
Deano, TAKE HER UP ON IT. Start with something around 180 horsepower. There is no substitue for horsepower.

Looked at a Cherokee 180, wife liked it and price was reasonable.

 

[Dean]

[Did I miss what type? 1580 & three people - 150 with jump seat?[/QUOTE]

Yes, C-150 with child seat.

 

[Jeff Oslick]

Looked at a Cherokee 180, wife liked it and price was reasonable.

A very nice plane. Little shy on leg room in the back, but all-around quite nice.

Jeff

 

[SCCutler]

I was taught to fly airspeed, and that has always erved me well. But do remember the first time I flew 4-up, just shy of gross, in a Warrior, on a really hot day. I kept thinking that there had to be something wrong, maybe the throttle had slipped, something; I could not believe the leisurely climb performance! It took a lot of self-control not to try to force it by pulling up the nose more.

Just a matter of discipline. She'll do what she'll do, and that's that.

 

[Let'sgoflying!]

Some of the best (self-) training I received was flying my 100hp 150 around here... the DA gets over 7500' quite a bit in the summer. Things improved a lot when I put the 150hp engine in!

 

[poadeleted1]

I was taught to fly airspeed, and that has always erved me well. But do remember the first time I flew 4-up, just shy of gross, in a Warrior, on a really hot day. I kept thinking that there had to be something wrong, maybe the throttle had slipped, something; I could not believe the leisurely climb performance! It took a lot of self-control not to try to force it by pulling up the nose more.

Just a matter of discipline. She'll do what she'll do, and that's that.

That's what I was taught too. The 172 will fly at the same speeds, you just need to adjust pitch to keep the speed where it needs to be for Vx/Vy. I don't think it has failed me yet....unless....do you see dead people???

 

[Bob Bement]

Dean, Next year at Gastons we will be looking to see what you fly in in. I had the same proplem with a Cessna 170 and then my wife said get more horsepower. So now I fly 9054N a 182.

 

[corjulo]

Thanks for sharing that.

It not easy to admit when we get scared, but man does is serve the piloting community as a whole!

 

[poadeleted20]

The mistake most pilots seem to make on climbing out under higher DA is to rotate to the same pitch attitude they are used to for their normal DA condition.

How do you figure that as a mistake?

I suspect this is what happened to you - even though you rotated at a higher speed, you pulled back to too high a pitch attitude and bled off all that extra airspeed and then some more, resulting in the near-stall.

More likely what happened is a downdraft from any of a number of possible causes (orographic, thermal, whatever). And in that case, a pitch change is needed to maintain the same AOA and speed to keep flying.

 

[poadeleted20]

Why do that? That just makes you go even faster (end of runway sooner) and likely puts you further away from Vx/Vy. Airspeed indicator is ram air pressure. Reduce the molecules (higher DA) and you have a higher TAS for the same ram air pressure (IAS) ... then you added 10 kts to that.

Keep in mind that the IAS for Vx goes UP as DA goes up (and the IAS for Vy goes DOWN). They meet in the middle at absolute ceiling. While most aircraft manuals have Vy's for altitudes up to 10,000 or higher, I've never seen a light plane manual that give Vx other than at sea level. The best way to estimate Vx at higher altitudes is to draw a graph of Vy vs altitude, and then draw a line from Vx at sea level to Vy at absolute ceiling -- that line should give a sufficiently accurate approximation of Vx at all altitudes from sea level to absolute ceiling for any practical purpose.

For the Tiger, Vx goes up two knots from SL to 10K DA, and the "normal" rotation speed of 55 KIAS is bumped up to 67 KIAS (Vx-5) for "short field" technique. If you rotate the Tiger at 55 KIAS in those conditions and try to lift off, you'll just sit there nose high in ground effect hanging on the prop without accelerating, until the trees at the end of the runway smack you in the face. Alternatively, if you pitch to and hold the "normal" 7 degrees nose up or so for takeoff at the "normal" rotation speed, you'll sit there on two wheels with a whole lot of extra drag from the increased frontal area of the nose-up attitude and the lift being generated by the wings, accelerating very slowly to a higher speed that you'd have lifted off using the short-field technique (lower AOA, more speed needed to get L to equal W), using a lot more runway.

I fly basically the same climbout and approach indicated airspeeds (based on what the correct numbers are) up here at 6183+ MSL as I do at SL even when the DA is 10,000ft. I am fairly notorious at lifting off when able then accelerating in ground effect to Vx/Vy before starting the climb since I grew up on a short soft field.

That's a good technique for soft fields, but not for high DA's. With the dramatically reduced power available on hot days at high airports, you are very likely to get airborne behind the power curve, without sufficient power to accelerate to Vx.

The best tactic for hot, high takeoffs is to use the book short-field technique, with speeds adjusted for the high DA (i.e., Vx is up a few knots due to reduced thrust). Keep in mind that on a hard surface, your airplane accelerates better with the weight on the wheels and both induced and parasite drag at their lowest (i.e., zero-lift AOA). And that's why book short-field takeoffs always call for a higher than "normal" rotation speed. When folks tell you not to add extra speed for high DA, they mean don't go over book short-field speeds, not that you should use the "normal" takeoff speed/technique if the conditions are near your performance limits. Remember that with enough DA, even an 8000-foot runway is a "short field" and you need the book short-field technique to take off safely.

 

[Dave Krall CFII]

Going south it is pretty much open, a few trees, cleared them by 200'+

More clearance is usually better but, 200 feet's not too bad usually.

A lot of times if I've got my critical airspeed by 1/2 down the runway then I pull AoA to fly as close to the obstacle as is safe and what ever airspeed/energy there may be in excess, is still available for downdrafts. If there is no excess airspeed/energy going over the obstacle, well then that would have been a close one.

 

[bbchien]

Keep in mind that the IAS for Vx goes UP as DA goes up (and the IAS for Vy goes DOWN). They meet in the middle at absolute ceiling. While most aircraft manuals have Vy's for altitudes up to 10,000 or higher, I've never seen a light plane manual that give Vx other than at sea level.

...and that is the ABSOLUTELY critical piece of information. Most pilots, when flying by the airspeed, use the same number, no matter at what altitude. The results are predictable.

 

[Anthony]

...and that is the ABSOLUTELY critical piece of information. Most pilots, when flying by the airspeed, use the same number, no matter at what altitude. The results are predictable.

Absolutely! At Sea Level, Vy on my Tiger is 90 KIAS. Departing Leadville, CO a few weeks ago at 10K ft. it was 79 KIAS. And believe me, I had it pegged at 79.

 

[Ed Guthrie]

Keep in mind that on a hard surface, your airplane accelerates better with the weight on the wheels and both induced and parasite drag at their lowest (i.e., zero-lift AOA). And that's why book short-field takeoffs always call for a higher than "normal" rotation speed. Remember that with enough DA, even an 8000-foot runway is a "short field" and you need the book short-field technique to take off safely.

(emphasis added)

Ron, you should remove your blanket advice above and stick to advising folks to read and follow the POH. For the record, the 1979 C152 & 172N POHs disagree in several areas wth your advice in this thread (well, not the "read the POH" advice), as does the Piper PA28-161 Cherokee Warrior information manual, as does the 1977 Mooney M20J POH, as does I will speculate a goodly number of other POHs.

 

[John J]

Dean;

Thank you for sharing your story; We all learn from our experiences and what is really nice is that we can pass them on to help others out there. Yes I had a simular situation in a Champ that was at gross on a very hot day. I was getting duel to get ready to solo and we had some wind shear just after we got off the ground. The pucker factor was high to say the least but I never forgot the CFI pushed the nose down to get speed. I was 16 at the time and I have never forgot that lesson.

John

 

[Let'sgoflying!]

goodly number of other POHs.

Heck a lot of planes out there do not have any V-speeds (let alone ones for different DAs) published in their manuals/POHs (like mine)! Just 'fly the wing'?

How about landing? I swear the sage advice here/AOPA board in the past was not to 'add 10kts' to 1.3Vso to compensate for DA. True still, or....?

 

[Jeff Oslick]

The mistake most pilots seem to make on climbing out under higher DA is to rotate to the same pitch attitude they are used to for their normal DA condition.

How do you figure that as a mistake?

Because the pitch attitude when climbing out at 800 fpm will be significantly steeper than climbing out at 250 fpm (both at the same IAS, the shallow climb of course being at high DA).

Jeff

 

[Tom-D]

My normal rotation speed is 60 so I up it to 70 to allow for the high DA.

That is a mistake Your airspeed indicator already feels the DA.

you need to add feet to the roll out, and take off distance but NOT airspeed.

Your ground speed goes up, to gain reaction from the high density altitude

 

[Let'sgoflying!]

That is a mistake Your airspeed indicator already feels the DA.

That is what I have been taught by a million people and in all the readings available to me.....and its also what I mentioned earlier in the thread. Maybe I am seeing it wrong but it seems like some here are saying you need to adjust the IAS you use for each DA. Or maybe the difference is truly beyond what an average pilot is capable ie 5kts for most a/c, most DA differences -- and we are down to splitting gnats whiskers. I eagerly await the responses.

 

[Dean]

Thanks to all that pointed out things that I did wrong, and those that pointed out what I did right. There is nothing better for a low time pilot like myself than hearing from the experienced ones here at POA. Your words of advise are helpful and taken to heart.

 

[Dave Siciliano]

There are also considerations when the plane has a retractable gear. From one of the instructors on the Bonanza Board concerning a recent crash reported in Utah where a micro burst or down draft is being discussed as the cause.

Dave
------------------------------------------------------------------------
Vx with the gear down is substantially lower than Vx with the gear up. The same is true of Vy. The current manuals only list a single Vx and Vy in the clean configuration. The original manuals have more detail, but you need to interpolate. As an exercise, I have the student do a go around from 50 feet, but leave the gear and flaps down. They are told to use the manual Vy. Of course, the airplane will barely climb, if at all, at that speed, in that configuration. Once they have seen this, they are instructed to climb using the book speed for "balked landing". The aircraft will then climb smartly at about 500 to 600 feet per minute. I explain to them that the "balked landing" speed is actually very close to Vy for that configuration.
For my V35A, I have the following IAS in mph at 3400lb GW, ISA, Sea level: Vx Vy

Clean 93 115

Gear down 80 96

Gear and Flaps 68 83

John Eckalbar has a chapter on this subject in his book "Flying the Beech Bonanza"

 

[Ed Guthrie]

There are also considerations when the plane has a retractable gear.
...
Vx with the gear down is substantially lower than Vx with the gear up. The same is true of Vy.

Amen. '77 M20J gear & flaps down Vx is 66 kts; gear & flaps up Vx is 72 kts. Furthermore, the Mooney M20J (and I suspect all electric gear Mooney) is potentially unique in that the obstacle clearance distance on take-off or go-around is improved if the aircraft is flown gear down until the obstacle is cleared. That tidbit nearly bit another Mooney pilot on a go-around at Smoketown.