737 glide ratio and speed
 

I have been trying unsuccessfully to find the boeing 737 classics glide ratio and speed (depending on weight for sure) . Please somebody direct me to where in the documentation to find it. i do know that in the QRH below 270 speed 300
and 275 above FL 270 is recommended however are those speed for glide ratio or increasing probability of successful starts.
i have seen some answers in previous thread however i still dont know where in the docs it is indicated

mamad

If my memory serves me correctly, it is the latter.

A rule of thumb is 2 miles per 1000 and 5000 for a 360 degree turn at min clean (210/220) which is as good as best lift /drag ratio that you will get following a double hush. Aim to be be at 4 miles at 2500 agl on the centreline at F5 170(180) there take flap 10 inbound and when certain you will make the field take gear down and flap 15.

The 275/300 kts is for engine start.
Best glide will be between 205 and 230 depending on weight and model of 737.

Can't remember it absolutely, but is there not a relationship between 'best angle climb speed' and best glide speed? This is slower than 'best ROC speed' so I think this will be closer to best glide. Someone will know.

I remember reading somewhere recently that glide ratio of big jets had hovered around 1:11 for a long time which roughly matches the 2 miles per thousand feet rule of thumb. If you have done any gliding you will know that weight does not negatively impact glide ratio, but will of course increase rate of descent and best speed. Not a lot of time is spent practicing for loss of all engines, which makes Sully's effort all the more impressive.

Lederhosen - (stopped wearing mine back around 1969).

18:1 767. Boeing data
757 slightly better - unknown amount
737W/757W approx. 19.5:1 personal observation using sink rates, TAS, etc, etc.

News report said 787 is over 21:1, and maybe 22:1.

Best glide speed is typically listed in the dual engine flameout charts.

Higher speeds mentioned by OP are for restarts, glide speed, as Framer noted, is in the low 200's depending upon aircraft model and actual gross weight.

Idle descents probably have slightly better than dead stick performance. Considering descents are 250 KIAS the gliding performance might be very similar to dead sticking at 220 KIAS(+/-). Verifying you basic performance by cross-checking if your target is raising, dropping, or staying steady in your window screen is learned before you solo. Sully mentions the decision that he wouldn't make TEB was immediate as he saw it rising in his windshield.

misd-again thanks for your input, the improvement in glide ratio from the classic to the NG and additionally with winglets makes sense. The 787 I doubt very much I shall ever experience from front left.

But with respect if you cannot get one or more engines started, flying around 210 knots and planning on two miles per thousand feet is about as much as you need to know and will have the capacity for while you try and manage the other priorities.

Extensive gliding experience by the way has helped a number of crews to a better conclusion, the Air Canada 767 (Gimli glider) and Air Transat A330 in the Azores being two good examples as well as of course Sully.

I have been a TRI on the 737 for a while and cannot ever remember our manuals containing dual engine flameout charts. (We do have an in-flight start envelope.) I may be having a senior moment, but I think most people will struggle to find the data you suggest. Can you post us a copy to tweak the old grey cells.

Max landing weight, dual engine glide speeds, for 5 different types, are between 215-240 kts.

All of our a/c, except one, publish dual engine flameout glide speeds.

18:1 is 3 n.m. per 1,000. I recall reading that Airbus recommends 2.5 per thousand.

If you're a TRE you can do this is the sim - 250 kts at 10,000'/40 DME or 250 kts @ 5,000'/20 DME(typical arrival 'energy' gates). IMO it's an excellent demonstration of the aircraft's gliding ability and energy/drag management.

It's nice to know, at least no wind, that you can deadstick from the descent profile and might, or will, reach the airport. If you're below the profile you also know instantly, as Sully did, that trying to glide to X is impossible.

Air Transat lost the second engine at approx. 34,500 65 n.m. from the airport, had to do 360's, and was still fast and high on final so 2 n.m per thousand is more than enough altitude/distance.

Pity this type of forced landing practice is not practiced regularly in the simulator. Instead we see engine failures on take off ad nauseum on every sim session, plus LOFT exercises on autopilot where the instructor piles on non-normal after non-normal changing destinations and weather and then throwing in the odd heart attack requiring medical advice from a phantom doctor who just happens to be in seat 5A and so on. Nothing much learned from all this apart from the utter impossibility of all these "events" coming together at the same time.

Whereas what is needed in the simulator is practical flying skills such as practicing strong crosswind landings, dark night black hole approaches sans glide slope guidance, raw data instrument approaches manually flown and of course dead stick landings from high altitude. High altitude and circuit altitude stall recoveries require manual flying skills and these need to be practiced, too.

Unfortunately, the box ticking magenta line automatic pilot brigade have the upper hand in choosing what simulator practice has the priority with the lessons of the Air France A330 accident having no impact on what is currently taught or practiced in the simulator.

I flew the B737 100, 200 and 300 before going to the B757. We did six legs a day so got idle descents down really good. We did high speed down to 10 at 2 times the altitude at 320 knots, then 250 to the approach point at 3 times the altitude then decreased speed for approach and most of us could do it 95 % of the time with no problem without using power from FL350 to 1000 ft. It doesn't happen that way much now with the Riddle pilots flying.

I think you are in serious need of an ego check and like many of your posts RTFQ...
They are talking about engine out glide speed not idle speed descent ,you muppet.:eek:

df,I know you are not in China but what makes you so angry about simple things like 737 descents? Engines out or idle. Maybe an anger management course is in your future. Did you take the quick course with Daddy's help?

Sorry about previous answer (deleted), I was confused with max range - max endurance.

Max glide occurs at max L/D which occurs at Vdmin. Vdmin is also the speed for max endurance (jets).

Holding tables all engines in the QRH are based on the following, higher of:
-Man speed.
-Max endurance speed.

You can use those speeds as glide speeds.

thanks
 

very informative thread !

Welcome to chinese sim sessions:E

Thank you guys for all this infos

i guess i will just stick with the 210 2nm per 1000 ft answer

eventhough that would have been nice to have a reference

mamad

mamad, 2X Alt will work just fine and is conservative so you can push it a bit if you want. The 737 100 and 200 aircraft didn't have high bypass engines so the idle thrust vs no thrust descent wasn't a lot different.

We practiced dead stick landings in the 737 in the sim and the descent was just slightly steeper. We would just stay a dot and a half above the glide slope or if no glide slope stay slightly high and dirty up to final flaps at 100 ft or so with a little extra speed to get you on a normal touchdown profile. The 737 800 might be closer to 2 to 1 than we were, 2.5 to 1.

We practiced a lot of dead stick landings flying business jets when empty in Lear Jets and Citations to sharpen our skills. If you ever become a Sully one day you will know what to do.

Going from a pilot mill to the right seat is great but you miss out on all the learning about flying you get from doing it a few years in the real world, not with a flight instructor and a syllabus.

Dual Engine failure in a B-737 classic
 

The action to follow is to start the A.P.U. immediately..If you are able to start the A.P.U., you can power an electric bus.If you power the left electric bus,this allows you to power the right electrically driven pump, which is powered by the left electric bus.Now, you can switch on the autopilot, and allow the autopilot to fly the plane at the best glide speed. This should be the "green dot" speed on the Airspeed indicator.This is the clean maneuvering speed..

After setting the orange bug at this speed, select level change and turn the Aeroplane towards the nearest Airport.By selecting level change on the MCP, the autopilot will maintain the best glide speed for you.In the case of a "Non glass" cockpit, maintain a speed of 210 knots or if above 53,000 kg, maintain 220knots on the airspeed indicator.After starting the A.P.U., the pilot monitoring will commence with the restart procedure by moving the engine start switches to the flight position, and the Engine start levers to the off position,then to idle,as shown in the QRH procedure.While this is ongoing,the pilot flying is managing the flight path.

The Boeing 737 classic's glide ratio is between 15:1 (Fifteen feet forward travel for every 1 foot of height), and 18:1 (Eighteen feet forward travel for every 1 foot lost). Do not select the gear, or flaps down, as this will decrease the glide distance. All you have now is the kinetic energy,due to your forward speed, and the potential energy,due to the height. Also, if your map display is available, the green arc will show your glide distance, but you must set the altitude selector on the mode control panel to the elevation of the Airport you are heading to,for the correct glide distance indication.

There are two methods for the approach and landing. If you are coming in on a straight in approach,plan on a 6 degree approach path.This is planning on being at 6;000 feet at 10 miles to touch down.If you are able to tune and receive an ILS signal to the runway,use the displayed information, to your advantage.Stay above the glide slope at preferably 2 dots above, but not lower than one and a half dots above the glide slope.With the field in sight,and the Aircraft glide path leading to a point further down the runway,you can start extending the flaps in stages.This will start bringing the aircrafts touchdown zone closer,towards the landing threshold.Flaps 1,then Flaps 5..

To extend the gear, you will have to change the electrical bus powered by the A.P.U. to the right bus.The right electrical bus powers the System A electric hydraulic pump,,on the left, which powers the A hydraulic system.After lowering the landing gear,you can change the A.P.U. powered bus to the left electrical bus.This will allow you to be able to lower flaps further.The landing gear extension will reduce the glide distance,which is why you mouse initially have a distance extending way beyond the threshold.Flaps 15, and also flaps 30 can be delayed, till just before touchdown, so as to ensure that the Aircraft reaches the runway.

In a case where the Aircraft will not get to the threshold, do not stretch the glide,until you get into ground effect, then you can flare to maintain altitude,and as your speed reduces,extend the flaps at the flap maneuvering speeds, in stages,to prevent the Aircraft from stalling.It is possible to stretch the distance to touch down in this way.

The other method of approach and landing is to arrive at 5000 feet above ground level, slightly to the right side of the runway,with the Captain just sighting the runway,and when abeam the threshold, start a left turn,while maintaining the maneuvering speed.At the maneuvering speed,while in a turn, every 90 degrees of heading change, the aircraft descends 1000ft.So a 180 degree turn will cause a 2,000ft altitude loss, while a 360 degree turn will cause a 4000 feet altitude loss. So,when the Pilot flies close to the threshold,in the direction of landing, and initiates a 360 degree turn,the height loss will be 4000 feet when completing the turn.The extra 1,000 feet added to make the altitude abeam the threshold 5,000 feet, is to cater for the extension of the gear, and flaps.The decision as to when to start flap,and gear extension should depend on whether one is on profile(above the normal glide slope) or getting below it..You must also remember that with the hydraulic pump powered, you can extend spoilers to reduce your height if required, and also after landing,spoil the lift,and help in slowing down the aircraft.The brakes can be applied also, with a continuous depression of the pedal.(Do not pump,or cycle the pedals)

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We tried to do an forced landing (engine out) in the B777 sim this morning.
I was on promising tracks but the TRI stopped the sim. He was afraid of the slope with flaps and gear out.

Can anyone confirm if their airline has some sort of "procedure" for an engine out pattern ?

In my opinion, it finishes with some flaps and gear down, which should give more than 2000fpm descending in an airliner. It will make the GPWS blare, which frightened the TRI...
But is there any other clean solution ? A clean solution would be to use kinetic energy to avoid a so high rate of descent, but in my opinion it's not a reliable technique.
Then, from a 2000fpm descent I would have flared at 200ft.

Also I disagree about the 5000ft minimum regarding the pattern from airfield vertical. We did it at 2000ft in the 777 and we almost made it. I did it from 3000ft and I was a few hundred feet above the runway.
It's more comfortable, though, to do it this high.