11 hours ago, Keirtt said:

I bought into the CE program. I think the crew at TFDI will put out a good product, but it'll take some more time after launch to develop into something solid. I'm waiting to see how their latest update feels to make a determination on the flight dynamics. Right now it still doesn't feel right and I feel like they're going to catch a ton of flak if it's not improved before launch. Very twitchy with the pitch.

You can mitigate that somewhat, with a positive Extemity Deadzone setting (in MSFS Control settings) for your yoke.  That's especially valid for an aircraft like an MD-11 which is larger.

19 hours ago, G550flyer said:

For sure! Some of my peeps went on to FEDEX as I moved on to corporate. You are right, they fly similarly, but I've been told that the augmentation on the MD-11's flight controls can be a little quirky during landing. They explained that at lower speeds, it can be a little sluggish to input. This was explained to me over a beer,detailing the Tokyo crash. They have stated due to the smaller empennage, it can't handle crosswinds as high as the DC10, so you are more subject to diverting due to crosswinds.     

Thanks for that info Rick. Great info. I didn't realise the MD-11 had a reduced empennage, specifically the HS, which does indeed seem to have a considerably reduced area. The VS appears to be about the same as the DC-10? 

If I understand correctly, the DC-10's (and MD-11's) wing mounted engines are actually mounted closer to the fuselage than would otherwise be optimum for wing bending relief and ZFW. This was apparently to ensure 1 or 3 engine out asymmetric controllability was maintained arising from the reduced rudder area occasioned by the inline mounted engine as compared to say the S-ducted L-1011. 

As an aside, I have always lived  some 30 nm north of Auckland airport so that many international arrivals and departures would fly over our place. Air NZ had DC-10's so it was not uncommon to see them or the ones operated by UTA (French Polynesia). but L-1011's were very rare and only seen on occasions when Cathay Pacific would turn up with one replacing one of their usual B747 schedules.  There was no way to reliably determine the tail configuration but the wing mounted engine spacing easily identified the occasional Tristar by its comparatively much wider spacing than then the narrowness of the DC-10's.   

Interestingly, this asymmetric design requirement played out in the B747SP which was easily distinguishable by its very short fuselage. This reduced yaw control and stability that this design created required more rudder authority particularly in asymmetric and crosswind situations. Accordingly, the SP had a VS that was some 5 feet taller than the standard B747, in order to accommodate its larger rudder. (But that does make the SP look pretty special!!) 

So with a longer fuselage and the same size rudder as the DC-10, and a roughly 20 knot higher landing speed I would have expected the MD-11 to have more rudder authority in a crosswind situation, not less? Although I guess the same cant be said for pitch control if the HS has been reduced so much. It seems like a drive to reduce drag has led them to reducing the HS area more than it should have been and having read some of the accidents you pointed to it looks like MD-11 is a difficult beast to control especially landing in crosswinds? 

I guess I don't quite understand the aerodynamics going on here. Is it the moments created by the tail engine during thrust adjustments that are not adequately compensated for by the less than favorable pitch authority, coupled with a sluggish augmentation system you mentioned? Or is it the rudder authority or a combination of both that leads to these challenging landings? 

I somehow don't think the TDFI offering will model any of this too well but if they do, there will be some interesting landings challenges thats for sure! 

Cheers

Terry

Edited May 18, 20242 yr by Lord Farringdon

I will disagree and say this Avsim forum can be "spicy" as well.

Even Poor 'ol Captain Piett got some haterade. Don't mess with, Piett ya'll.

I remember someone lashing out at me with all kinds of nasties because I thought the (back then) upcoming PMDG 737 seat textures were "good enough" for now. I was scrutinized over it and not using proper grammar. So, yeah. Anywhere can be hostile or in that case....just annoying and not helpful.

6 hours ago, sloppysmusic said:

Indeed but there are plenty of forums not so polite. I was referring to ALL Internet forums as a general rule. Of course there is definitely polarisation here too, just look at ASFS for a start! Much more polite though. 

Yeah, people are on the internet turn into immature-coward-toddlers and thats giving toddlers, cowards and immature people a bad name hahah

Edited May 18, 20242 yr by Sonosusto

4 minutes ago, Sonosusto said:

Don't mess with, Piett ya'll.

I second that. Dude is always patiently trying to help, often successfully lol, whereas some people are just...TRYING period.

😜

I spent many hours with the PMDG MD11 back in the day … felt very convincing as I recall … now tempted to see if I can work out how to set up FSX after all these years.

26 minutes ago, tfm said:

I spent many hours with the PMDG MD11 back in the day … felt very convincing as I recall … now tempted to see if I can work out how to set up FSX after all these years.

Me too. Had maybe TOO much fun with it!

"My mother said I could do anything if I put my mind to it"

"This is your captain speaking. Those on the left can notice 6 types of local fauna and some rare lichen for those of you seated on the right.."

Never in doubt!

22 minutes ago, sloppysmusic said:

Me too. Had maybe TOO much fun with it!

"My mother said I could do anything if I put my mind to it"

"This is your captain speaking. Those on the left can notice 6 types of local fauna and some rare lichen for those of you seated on the right.."

Never in doubt!

Happy days!

Actually installing FSX and the MD11 was pretty quick AND amazing to see how fluidly it all works with modern kit (what would you have given for 70+fps in the MD11 in c2008?) … BUT … it just can’t compete even remotely with MSFS from the point of view of anything else really 🙂 

The PMDG MD-11 was my favorite plane by far. Miss it. Spent some time in a FedEx sim, flew exactly like the PMDG. Going to be hard to meet that quality of flight dynamics. 

13 hours ago, Mace said:

You can mitigate that somewhat, with a positive Extemity Deadzone setting (in MSFS Control settings) for your yoke.  That's especially valid for an aircraft like an MD-11 which is larger.

Good to know. I'll test it. Thanks

If pre-ordering now for $80.00 USD, will the release be for the passenger or cargo version or both? To me, it's not too clear on their site.

On 5/18/2024 at 10:43 AM, Lord Farringdon said:

Thanks for that info Rick. Great info. I didn't realise the MD-11 had a reduced empennage, specifically the HS, which does indeed seem to have a considerably reduced area. The VS appears to be about the same as the DC-10?

Looks the same to me as well. I did a little research and the crosswind limits come in at 35 vs the DC10s 31. Now, I was told it was recommended to do 25. I was wondering if the guy told me that because of the handling. Now, I have done 31 knots of crosswind in the DC10 and I had full rudder and my leg was shaking trying to keep that segmented puppy wrapped all the away around. On the first approach, winds gusted higher than 31 and I had full rudder and almost all aileron and it was still drifting in the flare and touchdown causing me to go around to keep from going off the edge. I can only imagine 35 knots in the 11.

 

On 5/18/2024 at 10:43 AM, Lord Farringdon said:

I guess I don't quite understand the aerodynamics going on here. Is it the moments created by the tail engine during thrust adjustments that are not adequately compensated for by the less than favorable pitch authority, coupled with a sluggish augmentation system you mentioned? Or is it the rudder authority or a combination of both that leads to these challenging landings? 

Well, both planes have high wing loading with those stubby wings compared to the fuselage. When she gets slow, she loses a little of that snap she has when finger tip flying at cruise or during air refueling😉. On paper, the 11 is longer, so the tail being further back makes sense to be smaller, but they reduced for drag as well. Maybe this is where that augmentation comes in. LSAS supposedly makes it fly similar to the 10 in pitch. We know with high wing loading, that we lose a little maneuverability. The 10 already had some high takeoff and landing speeds and the 11 has higher. One thing about the 10 and 11 is that you can get into high sink rates if you are not careful. With that in mind, you have to anticipate and add corrections earlier due to that maneuverability. When landing near max landing weight, you feel the inertia. In fact, it acts like three different type of airplanes. The heavy, medium and light types.

As you can imagine, depending on the jet's weight, you account for that inertia. When heavy, you have to flare and pull that power early because it's slow to react and you won't lose speed. If light, you have to keep that power in longer and flare later or else it will run out of speed quickly and drop in. We used the 10% technique. 10% of your landing weight was your flare height. 10% of your gross weight plus 23 were your N1 settings for approach speed on a 3 degree with flaps 35.    

Now the question for the 11 is, is the challenging approach a result of LSAS dampening your pitch inputs or is it peeps not anticipating and getting into sink rates and responding too late. As you can imagine with the 10/11, snatching back on the yoke in a last ditch effort to save a landing only pushes the mains faster into pounding the runway. You are better off goosing the power and riding it in. 

On 5/18/2024 at 7:42 PM, Sonosusto said:

I remember someone lashing out at me with all kinds of nasties because I thought the (back then) upcoming PMDG 737 seat textures were "good enough" for now. I was scrutinized over it and not using proper grammar. So, yeah. Anywhere can be hostile or in that case....just annoying and not helpful.

Infantile hate, flame wars, and suddenly out of the blue getting group-attacked like a gazelle in the middle of the Savannah by hyenas in certain highly problematic forums (not this one, but others) is not coming from "normal" users a.k.a. the common typical chilled laid-back PC flight simmer or gamer mostly ranging age 25-40 who just love aviation and just want the best product for their money.

But from a lot of marketing and PR guys of certain corporations that are in hiding in all the typical bigger English-speaking sim forums, only waiting to pounce and attack mock disgrace humiliate gang-stalk and mass-flag anyone who dares to critizice their product. 😉 

 

8 hours ago, G550flyer said:

Looks the same to me as well. I did a little research and the crosswind limits come in at 35 vs the DC10s 31. Now, I was told it was recommended to do 25. I was wondering if the guy told me that because of the handling. Now, I have done 31 knots of crosswind in the DC10 and I had full rudder and my leg was shaking trying to keep that segmented puppy wrapped all the away around. On the first approach, winds gusted higher than 31 and I had full rudder and almost all aileron and it was still drifting in the flare and touchdown causing me to go around to keep from going off the edge. I can only imagine 35 knots in the 11.

Hi, MD11 crosswind limit is given with 35 kts for TO and LDG (manual) and for dry runways, for wet/contaminated runways limit decreases to 25 kts until 5 kts for poor braking action, for automatic landing max 15 kts and lower applies depends also on rwy condition. Best regards

On 5/20/2024 at 11:36 AM, G550flyer said:

Looks the same to me as well. I did a little research and the crosswind limits come in at 35 vs the DC10s 31. Now, I was told it was recommended to do 25. I was wondering if the guy told me that because of the handling. Now, I have done 31 knots of crosswind in the DC10 and I had full rudder and my leg was shaking trying to keep that segmented puppy wrapped all the away around. On the first approach, winds gusted higher than 31 and I had full rudder and almost all aileron and it was still drifting in the flare and touchdown causing me to go around to keep from going off the edge. I can only imagine 35 knots in the 11.

 

Well, both planes have high wing loading with those stubby wings compared to the fuselage. When she gets slow, she loses a little of that snap she has when finger tip flying at cruise or during air refueling😉. On paper, the 11 is longer, so the tail being further back makes sense to be smaller, but they reduced for drag as well. Maybe this is where that augmentation comes in. LSAS supposedly makes it fly similar to the 10 in pitch. We know with high wing loading, that we lose a little maneuverability. The 10 already had some high takeoff and landing speeds and the 11 has higher. One thing about the 10 and 11 is that you can get into high sink rates if you are not careful. With that in mind, you have to anticipate and add corrections earlier due to that maneuverability. When landing near max landing weight, you feel the inertia. In fact, it acts like three different type of airplanes. The heavy, medium and light types.

As you can imagine, depending on the jet's weight, you account for that inertia. When heavy, you have to flare and pull that power early because it's slow to react and you won't lose speed. If light, you have to keep that power in longer and flare later or else it will run out of speed quickly and drop in. We used the 10% technique. 10% of your landing weight was your flare height. 10% of your gross weight plus 23 were your N1 settings for approach speed on a 3 degree with flaps 35.    

Now the question for the 11 is, is the challenging approach a result of LSAS dampening your pitch inputs or is it peeps not anticipating and getting into sink rates and responding too late. As you can imagine with the 10/11, snatching back on the yoke in a last ditch effort to save a landing only pushes the mains faster into pounding the runway. You are better off goosing the power and riding it in. 

TLDR: Cant wait for the TDFI MD-11.

Thanks again Rick for sharing your IRL experience with these aircraft. That go around in those conditions right on the edge of crosswind limits must have made you ask yourself the question, "Why didn't I become a Bank Clerk instead......?" 🙂   

"....both planes have high wing loading with those stubby wings compared to the fuselage." 

Well, I guess that explains the sink rates, and the need to anticipate them.  

"Now the question for the 11 is, is the challenging approach a result of LSAS dampening your pitch inputs or is it peeps not anticipating and getting into sink rates and responding too late. As you can imagine with the 10/11, snatching back on the yoke in a last ditch effort to save a landing only pushes the mains faster into pounding the runway. You are better off goosing the power and riding it in."

That's a really interesting question and I suppose it raises another question of why LSAS even exists and whether it has had a part to play in some of these landing accidents the MD-11 has experienced. I guess when they were looking at drag reduction in the MD-11 there weren't many options. Putting some winglets on no doubt helped reduce induced drag. The stabilizer had trim tanks so the stab didn't need to create drag in cruise. When it came to the tail they must have also wanted to reduce fin and rudder size but with the engine arrangement that really couldn't be done so elevator surface area was their only remaining candidate. Whether that was a right decision given the heavier weights of the 11 and the already high wing loading and approach speed characteristics, who knows, but it seems throwing another 20 knots or so onto the TO and LDG speeds was deemed compensation enough for these phases of flight. On one account I saw an MD-11F pilot recalled a 168 kt landing speed at MGLW. That's fast and pilot reaction time is greatly reduce at these speeds. 

But it seems the reality was that the design of the smaller stabilizer for reduced drag and fuel saving invited less longitudinal stability and so the MD-11 entered service with LSAS (Longitudinal Stability Augmentation System) which partly compensated for unwanted pitching. This software was modified for the operators and in the case of Fedex was made to give the MD-11 the feel of the MD-10 so that a common type certification could be achieved. However, some ex MD-11F pilots seem to be of the view that if you found yourself landing in adverse weather, you had better know which aircraft you were flying because they were significantly different!  

The following information is derived from various comments throughout the internet mostly made by real MD-11F pilots or engineers. 
  
While LSAS did many good things in the TO, climb, crusie and decent phases such as Pitch Attitude Protection (PAP) to prevent tail strikes, improved Pitch Rate Dampening, Speed Protection and Stall Protection, it may have had a somewhat less than favourable pilot reception during an AP OFF approach. It seems 'Elevator Feel' was not as it should be and may have led to some PIO. LSAS is off below 100 ft RA except for Positive Nose Lowering (PNL). During landing, after spoiler deployment is commanded, LSAS initiates PNL to assist in transitioning the nose wheel to the runway after main gear touchdown.

With regard to Fedex Express Flight 80 which crashed at Narita, Japan on March 23 2009, I wonder what LSAS in approach and PNL after touchdown did to aggravate the situation rather than enhance it. There is a Fedex 80 video on You Tube if you want see it, but  in that video you can see spoilers deploy and this is followed by a heavy nose down pitch causing another final bounce into the air. Presumably that was the LSAS PNL kicking in just when a go around would have been a better idea. (IMHO)

As a result of accident investigation, the Japanese Transport Safety Board published its final report a number of new safety recommendations which included that: 

"in order to reduce the occurrence of MD-11 series airplanes' severe hard landing and bounce in which an overload is transferred to the MLGs and their supporting structure, the Boeing Company should improve the controllability and maneuver characteristics by improving the LSAS (Longitudinal Stability Augmentation System) functions...."

I haven't seen the whole report but if PNL was active at this point it seems to be another case of pilots having critical pitch choices made for them by augmentation software.  As one ex MD-11 F pilot said: 

"Despite many software upgrades (issued by Boeing as the new OEM) of this LSA system the pitch control of the MD11 during landing remains "questionable" , especially in adverse weather conditions."

Having said all that, this should be balanced by many ex MD11F pilots praising the aircraft and LSAS while acknowledging that the aircraft could be a handful to land in some circumstances, "It was fine so long as you brought best game to the airport when flying her" said one Fedex pilot.  Another said, "....the MD-11 doesn't fly like other airplanes. It flies like an MD-11."   

 

The following is just interesting comparisons I made. 

MDD: McDonald Douglas were looking at developing a twin engine wide body to rival the B777 but company dynamics and speed to service was best achieved by modifying the existing albeit now old generation DC-10. 

BOE:  Boeing chose to upgrade the B737 to the MAX in order to compete against the A320 instead of creating a new up to date design 

 

MDD: A number of modifications to the MD-11 we re made to reduce drag and return fuel savings including the reduction in the size of horizontal stabiliser. This modification introduced pitch instability which needed software to overcome.

BOE: Boeing introduced the new Leap engine with improved thrust to increase payload and improve fuel efficiency. The more forward mounting of these engines modified lift so that control forces in turns were the opposite of what was conventional and needed software to overcome.  

MDD: Longitudinal Stability Augmentation System (LSAS) software was introduced to overcome pitch instability. This automation give commands to the elevator.

BOE: Maneuvering Characteristics Augmentation System (MCAS) software was introduced to improve handling characteristics. This automation gives command to the stabiliser. 

BOE: After taking over MDD,  Boeing modified LSAS to allow Fedex to achieve MD-11 common type certification with the MD-10, even though both aircraft handled differently.       
BOE: Boeing created MCAS for the B737 MAX to allow common type certification for B737 Operators but Max pilots were not aware and/or not trained on MCAS.  

MDD: LSAS did a lot of things to control pitching maneuvers in various stages of flight. The larger Operators provided good training on the system (Fedex has a 61 page document on how to land the Md-11). Despite this a number of crashes have occured and many have attributed to pilot error. 
BOE:  MCAS did a lot of things to control pitching maneuvers in various stages of flight but its implementation caused a series of accidents involving tragic loss of life. Pilots were initially blamed before Operators and pilots were given the information about MCAS and the necessary training. 

MDD:  The effect on McDonald Douglas: McDonald Douglas was acquired by Boeing through merger.
BOE:  The effect on Boeing:  After the merger, Boeing's CEO was ex MDD and ex MDD managers who were more focused on cost savings and shareholder wealth, played a role in managing Boeing after the merger. This has led to a general decline in Boeing as a once proud aviation company. 
   
    
Cheers

Terry

Edited May 21, 20242 yr by Lord Farringdon

LSAS as elevator input without CC feedback is active only with AP OFF. Best regards