Stall on approach 747

I've just attempted a landing at Dubai, and after six hours of flying, I managed to stall and crash a couple of miles short of the runway. I've had a few successful landings in a 747 and a fair handful in 737 and Airbus A321, so I'm not entirely new to landing jet planes. I checked the kneeboard manual which said my approach at full flaps should be 135 knots. I thought this seemed a little slow, but I trusted the guide- after all, I didn't design the 747 myself- and lo and behold, I stalled because I was going way too slow.

 

 

Is the guide wrong (most likely not) or is there a trick I've missed?

 

Cheers guys

What did you weigh on approach? Depending on gross weight on approach, you might have needed to be descending at 180 knots or so. You also need to remember those speeds are based on standard rate descents, not level flight. Plus if you get Low and Slow a turbo jet can't ramp up speed and torque nearly as fast as a recip. can!

 

RW: Many a recip. pilot has stalled a turbo jet or turbo prop when expecting it to ramp up like a recip. does. That's what killed Thurmond Munson. He was a low hour Citation pilot and stalled it out!!!!

I was pretty loaded with fuel in excess of 250k lbs. I guess the lesson here is to use my own judgement rather than blindly follow a manual

I was pretty loaded with fuel in excess of 250k lbs. I guess the lesson here is to use my own judgement rather than blindly follow a manual

 

That's way too much fuel for landing! You should plan to have no more than 40-50K lbs. That's should be enough for go around or divert to another field. Landing speed should be 155 knots at that weight.

That's way too much fuel for landing! You should plan to have no more than 40-50K lbs. That's should be enough for go around or divert to another field. Landing speed should be 155 knots at that weight.

 

That's what I said! Bunny Bread!!;);)

 

Me thinks he Tanks Alot!!!

What did you weigh on approach?

Probably about the same as he did when he took off, give or take a lbs or two. Even I can't gain a lot of weight on a six hour flight, even if I eat all I want.

And, I don't care how gross you think that is!

:D :D :D

 

Plus if you get Low and Slow a turbo jet can't ramp up speed and torque nearly as fast as a recip. can!

Except the F/A-18. Even the NATOPS says the engine response if nearly instantaneous. If you want, I can dig the passage up.

So there, neener!

The exception that proves the rule, I think.

 

Generally, though, the jets do spool up pretty fast above 80%. That's why you hear the commercials spool up on short final. That way the engines will respond if you need a go-around, or whatever.

 

Have fun all!

Pat☺

That 135 value is not correct. (Most other values are ok in that list, but use common sense.)

The max flap speeds are correct.

On landing, use full flaps. Max speed full flaps is 180.

Come in at low weight (low fuel), full flaps, and speed a little below 180. 160-155 is absolute minimum in the default 747.

Mainly, look at pitch. That will tell you if you are at a good speed. Too slo and your pitch will be too high. You can call that own judgement, yes.

 

Climbing at full flaps if difficult. So in a go-around, climb slowly.

During the final, when the hold light has gone off, I pre-set my autopilot to 3000ft, and a 100 or 200ft/min climb.

All that's needed to go around is to then engage the autopilot altitude hold and heading hold again. Works every time. Once climbing I slowly increase the climb speed.

 

Engine spool up time in fsx in the default planes is no issue. If you manually push the throttle to full, the reaction is there right away.

0 to full in less then 2 seconds.

 

Trust your instincts, it sounds like those are good.

 

 

Except the F/A-18. Even the NATOPS says the engine response if nearly instantaneous. If you want, I can dig the passage up.

So there, neener!

The exception that proves the rule, I think.

 

Generally, though, the jets do spool up pretty fast above 80%. That's why you hear the commercials spool up on short final. That way the engines will respond if you need a go-around, or whatever.

Pat☺

 

OK Pat,

 

A 747 isn't exactly a direct comparison to a F-18, even at 80%.

 

And I won't argue with il88pp either. One of the issues I have with FS is the turbo speed ramp up is often much faster than RW.

 

Regardless, SPEED VERSUS GROSS WEIGHT OF THE AIRCRAFT is the issue here.;) Though I will say, flying the plane from the cockpit instead of watching it from the Tower is certainly a step up!:p:p

 

Let's not talk about personal gross weight here!:o:o Mine went to hell in a handcart after all the chemo I've had! (Or that's what I blame it on anyway.):rolleyes:

 

Michael

I've just attempted a landing at Dubai, and after six hours of flying, I managed to stall and crash a couple of miles short of the runway. I've had a few successful landings in a 747 and a fair handful in 737 and Airbus A321, so I'm not entirely new to landing jet planes. I checked the kneeboard manual which said my approach at full flaps should be 135 knots. I thought this seemed a little slow, but I trusted the guide- after all, I didn't design the 747 myself- and lo and behold, I stalled because I was going way too slow.

 

 

Is the guide wrong (most likely not) or is there a trick I've missed?

 

Cheers guys

 

Hi, joshleedsfan.

 

I spend a lot of time in both the default (modified) 747-400 and the PMDG 747-400/8i and I found that despite their differences realism-wise there is a basic performance table (below) that works if you use your own judgement to adjust your climbout (I typically climb out at 1500 fpm when fully loaded, 1800 -- 2000 fpm with 1/2 fuel or less), cruise, approach speeds and flap configuration. I usually touchdown at around 140-150 kts, full flaps, with my speed about 154 kts by the time I reach short final.

 

One thing that may help is to know that the 747-400 burns roughly 24,000 -- 27,000 lbs of fuel per hour, sim-wise, and you can see your fuel burn rate by switching the EICAS knob to position 2 which shows the jet's Fuel Flow per engine, per hour.

 

When I plan a flight in FSX (using the high altitude airways, usually) I never trust what the planner lists as my estimated fuel usage because it's far from accurate, and doesn't take into account climbout, headwinds, etc, so I base my needed fuel on how long in hours the flight will take: A 2-hour flight will need at least 50-54,000 lbs of fuel, plus 1 hour 15 reserve, so I would load about 86,000 lbs of fuel in my tanks, plus more if the winds at altitude are headwinds (your estimates will vary, of course) just to be safe. When I'm flying with a VA airline I typically go lighter on fuel aboard because you get "paid" more if you land with the bare minimum of fuel in the tanks, so instead of the 86,000 lbs of fuel onboard as mentioned above it would be closer to 60,000 lbs (shame on me! :eek: ).

 

It's a tricky thing to predict actual fuel needed for a flight and more than once--yesterday, in fact, on a VA airlines flight from KSAN to CYVR--I've run out of fuel because I burned more fuel fighting a 99kt headwind that I had expected; yesterday I ran out of fuel right after I exited rwy 26R at CYVR. The VA "paid" me really well for that flight! ;)

 

Too, you don't want to start a 747-400 flight with full tanks unless you plan on flying a non-stop long haul, and landing with about an hours' worth of fuel onboard because the Maximum Gross Landing Weight shouldn't exceed 630,000 lbs.

 

Here's that *basic* performance table that I mentioned, and I hope that it'll be useful:

 

747-400

Passenger capacity

Typical three-class 416

Range, mi (km) 8,380

(13,480)

Maximum gross weight, lb (kg)

Takeoff

800,000 to 875,000

(362,880 to 396,900)

Typical operating empty weight, lb (kg)

398,780

(180,885)

Engines

Maximum fuel capacity, U.S. gal (L)

(with optional tail fuel)

Pratt & Whitney PW4000 57,285

(216,820)

General Electric CF6-80C2

 

57,065

(215,990)

Rolls-Royce RB211-524 57,285

(216,820)

Lower-hold cargo volume, ft3 (m3)

With pallets/containers + bulk

5,332

(151)

With containers + bulk

6,025

(170.8)

 

BOEING 747-400 REFERENCE INFORMATION

 

Maximum Range 8,400 nm

Service Ceiling 41,000 ft

BOW 397,000lbs.

Cargo 189,000lbs.

ZFW 500,000lbs.

MGTOW 870,000lbs.

MGLW 630,000lbs.

 

Set Fuel Load from ZFW 500,000 lbs.

Takeoff Power Reference @ MTOW 870k lbs.Dry Conditions

Average 10k ft. Runway is 109.9% N1. Max 117.2% N1.

 

V1 = 158 KIAS

Vr = 175 KIAS

V2 = 187 KIAS

 

Flaps 10-5 at 185 KIAS

Flaps 5-1 at 205 KIAS

Flaps 1-0 at 235 KIAS

 

Climb 1800 - 2500 fpm to 10,000 ft.

Climb 2000 fpm. to 16,000 ft. at 95% N1

Climb 1300 down to 500 ft/min from 16,000 ft. to Cruise Altitude.

 

Speeds: 250 ias. to 10,000 ft.

Speeds: Mach .50-.60 from 10,000 ft. to 16,000 ft.

Speeds: Mach .60-.79 from 18,000 ft. to 31,000 ft.

Speeds: Mach .80 above 31,000 ft. 91% N1

 

Cruise Airspeed: Mach .80 -.88 91% N1

Average burn rate 24k lbs per hour .

 

Approach Airspeed: 220-234 KIAS, 50% of N-1

Flaps 0-1 - 213 KIAS 11 DME

Flaps 1-5 - 194 KIAS 9 DME

Flaps 5-10 -174 KIAS 7 DME

 

Target Airspeed: MLW 630k lbs.

Flaps 20 - 159 KIAS

Flaps 25 - 154 KIAS

Flaps 30 - 148 KIAS

 

Thrust reverse to 80 KIAS

Apply brakes under 80 KIAS

Exit Runway Under 15 Knots

 

The maximum fuel capacities for the 747-400 do vary from the list above, but the rate of fuel burn is still 24--27,000 lbs per hour.

 

Happy Flying!

 

APUtech

@aputech

 

Welcome back from wherever you were!:D

@aputech

 

Welcome back from wherever you were!:D

 

Why, thank you, Mr. Zippy! Great to see you! It has been a while since I've posted here, but I do come by and read the posts!

 

I've been doing quite a bit of online flying (FSX:SE, XP10/11) on Steam since just over two years ago, and since I'm semi-retired I have plenty of free time to do it. Heck, in the two years and (about) three months since I'd gotten FSX:SE I've logged about 5400 hours on it, mostly in the 747. One would think that after simming for over 30 years one would tire of it, but there's still so much to learn (about the 747 especially) and refine my skills that I haven't suffered sim burn-out yet!

 

Too, I still go up and fly whenever I get the chance (actually it's more like a friend is flying somewhere and asks if I want to come along ;) ) and with the new FAA Medical regs becoming effective next month I won't have to fill out reams of paperwork because of my medical condition, so I'll be able to rent a plane and fly left seat again, wheeeeeee! :D

 

Well, I'm going to get back into the UPS 747-400BCF right now, so you please have a great flight!

 

Happy Flying!

 

APUtech

What a detailed and helpful post Aputech!!!!

 

And congrats on being able to go left seat again as well! Sadly I'm told my chances of that ever happening again don't exist.

 

Michael

I also thank you for the data you gave. I found in the FSX manual re: B-747's that there is a "max. taxi weight of 853K lbs". Another bit of info was that the programmers for FSX programmed the 747 to a default max weight less fuel. So fuel seems to be the primary factor in determining limits to flying the plane. If this is true, then it would put Joshleedsfan's example roughly about 64 tons overweight on landing. Again, thanks for the B-747 data. I'm assuming your second set of numbers in parenthesis are metric numbers? Oh, yes, what does "ZFW" mean? Gipper

Oh, yes, what does "ZFW" mean? Gipper

 

Zero Fuel Weight

What a detailed and helpful post Aputech!!!!

 

And congrats on being able to go left seat again as well! Sadly I'm told my chances of that ever happening again don't exist.

 

Michael

 

Thank you, sir! I'm eager to get up there and marvel at the "frame rates" I get from 5000 ft. ;-)

 

I'm really sorry about the news of your flight status. I do know what flying can mean to a man. I'm thankful that simming keeps that passion for flying alive, for those of us that embrace it; it's let me fly 747s and other neat airplanes that I wouldn't be able to for real and fills that need that we have to feel a sense of accomplishment.

 

Simming rocks! :cool:

 

Happy Flying!

 

APUtech

IRL you don't use manual braking. If they aren't inop you always use autobrakes for landing.

On the other hand you normally don't use anything more than idle reverse after touchdown. (Most airports don't even allow use of more than idle reverse)

Nevertheless you cancel reverse at 80kts even if it's only idle reverse.

 

BTW, even maximum reverse thrust without brakes results in very little (too little) deceleration.

 

We're not talking about IRL, bbrz, and yes, while 747s use autobrakes at touchdown coupled with the T/Rs on rollout, the T/Rs are sufficient enough to bring the airplane to a stop without applying manual braking, but on several flights on 747s in the past I have felt and heard the pilot applying manual brakes during landing rollout (you can hear them groaning and feel the deceleration, much like slowing down for a red traffic light) before exiting the rwy to the taxiway.

 

I have a Boeing 747 Operations Manual that I d/l from Boeing somewhere on one of my computers and when I locate it I'd be happy to upload it to you. Within, it discusses landing procedures for different scenarios--wet pavement, dry, icy, snowy--and the braking procedures for each scenario. Manual braking is not as rare a thing as you are given to believe. :)

 

There are several videos on Youtube that follow the exploits of a Lufthansa 747-400 cargo pilot (now retired) that clearly show his use of manual braking after the T/Rs are retracted. There are about 10 or so such videos and they were used in part to help me better understand the techniques of flying the "Queen."

 

Here's a link to a video where the Lufthansa 747-400 Captain clearly says "Manual brakes." during rollout at time mark 14:20.

 

 

 

 

Happy Flying!

 

APUtech

1. You are not talking about RL. That's why wrote the post. As you can do in FSX whatever you want, I want to explain how it is done IRL.

 

2. That's not possible for 2 reasons. First, you would need an extremely long runway if this would be possible.

Furthermore you can't use reverse below approx 60kts on the 747, 767 etc without destroying the engine as the engines will suffer from violent compressor stalls at low speed.

 

3. That's something different. Again, you normally always use auto brakes, but as the 747-400 doesn't have a brake to vacate function you need to switch from auto brakes to manual braking before vacating the runway. You certainly don't want to come to a full stop in the middle between two taxiways.

Keeping the centerline after touchdown is difficult enough with the pedals, applying 100% symmetric braking at the same time makes this task even more difficult.

 

4. The wording 'manual brakes' or 'manual braking' means that the pilot flying is actually DISENGAGING the auto brake system!

After disengaging the autobrakes you either increase braking to vacate via the next taxiway or stop braking at all to let the aircraft slowy decelerate towards a taxiway further down the runway.

 

Another point is the speed at which you should vacate the runway. High speed turn offs are designed for speeds up to 50kts and it makes the ATC seperation task much easier if you don't slow down too much.

 

Lol! :D Wow. I'm assuming from your fervent reply that you're an ATP?

 

I'll clarify: We (the OP and I) were not talking about real life, therefore I find your detailed reply irrelevant because it doesn't apply to FSX (though I did mention manual braking by the pilots of the 747s that I was a passenger on ;) )

 

I offered him some information pertinent to the FSX 747-400.

 

Happy Flying!

 

APUtech

It's only irrelevant if you don't want to operate the 747 in a realistic way, but I assume that there are a few FSX users who would like to do so.

 

Furthermore in my first reply I did post a way how to e.g. determine the correct approach speed for all weights.

 

(The sound of crickets chirping...)

I have come to the roundabout value of 25K lbs/hr. seems to work pretty well. 7 hr flt, 175K of fuel.

 

 

Sent from my iPhone using Tapatalk Pro

Thnx for your replies bbrz! I found them very informative and helping!

 

 

Grtz., Hans