Hi all

 

Santos Dumont (SBRJ/SDU) is one of the most challenging destinations; hence it's also one of my favorites.

Most of the time I fly from Sao Paulo (SBSP), as that route makes an interesting return flight as well.

I use the 737-800SFP with GOL painting.

 

I'm getting quite good at landing at SBRJ. Occasional go-arounds due to late cockpit preparations still happen, but that airport requires you to be pretty precise.

I was wondering what limitations there are for takeoff and landing at SBRJ, and searched this and other forums for answers. This is what I ended up with:

 

SBRJ T/O

Only RWY 20L/02R

Tail Wind max 5kt

Max OAT = 40c

Flaps 15 / 25 (15 = best performance)

Max TOW: 68K (Wet =64K)

Opt for Bleed off (Only very little gain)

27K TO-B (Always)

No rolling. Release brakes at N1=70% Then TOGA

Thrust reduction/Acceleration = 820’ / 820’

Speed mode = N1

VNAV engaged @ Transition ALT = 5000’

Assumed Temp. Max. 44c

 

SBRJ Landing

Tail Wind max 5kt

Only 20L/02R

Flaps 40

Autobrake MAX

Max LW 58.2

 

It’s the very last bullet (max landing weight 58,2 tonnes) that I never seem to get even close to. I’m mostly well above 60 tonnes when I land!

 

This is the post I got the number from: http://forum.avsim.n...-field-package/

 

So, these are my calculations:

 

Dry weight = 41,413kg

Reserve fuel and final taxi fuel = 3,000kg (incl unused holding, alternative and contingency)

166 PAX + 10kg carry-on = (80kg+10kg)*166 = 14940kg

Luggage = 166pax * 15kg (average checked in luggage) = 2490kg

No extra cargo

 

Total landing weight is then 61,843kg!

 

I’m often told, that I need to lose weight :-), but here we are talking about 3.6 tonnes !

 

I haven’t overrun the runway yet, so it might be the 58.2 tonnes max landing weight, that’s not right. But it really sounded like the poster knew what he was talking about.

My guess is that my calculations are wrong. But I can’t really see where?

 

Any help, knowledge and guidance is appreciated.

 

Thanks in advance.

//Lasse

Total landing weight is then 61,843kg!

I’m often told, that I need to lose weight :-), but here we are talking about 3.6 tonnes !

I haven’t overrun the runway yet, so it might be the 58.2 tonnes max landing weight, that’s not right.

 

Might be. It's too many factors to calculate stopping distance for every case. In performance docs there are reference landing distances.

Also SFP gives additional 8000lbs (exaclty 3629kgs!).

You are using way too high estimates for pax weigth. ISO of 90kgs you use, you should use something more like 80kgs. You can also do with a little less reserve, 2.2, 2.3 should be OK. With this you are good two tonnes less. Now, you are still over your limits, and it is time to offload passengers. Send about 10 of them to Galeao instead :)

 

Anyway the fact that you did not overrun does not mean MLW is wrong. MLW is computed with performance reserve, without reverse thrust etc. The difference between safe and unsafe, is not what did not happen, but what could not happen, i.e. on takeoff, if you lifted off on two engines on last 200m, takeoff was unsafe, because if you had lost one engine on V1, you would not have been able to continue nor stop.

 

Rostyslav, 58.2 tonnes is SOP maximum with SFP factored in.

Here Look at the calculation:

 

Even with values reduced you'll never get close to 58.2. There's 183 - 187 seats in the GOL 737-800SFPs.

If they weren't supposed to fly full, then why not stick with the 737-700?

It's usually a business flight.

Less carry-on and much much less luggage.

Less carry-on and much much less luggage.

 

Good point with luggage.

 

 

Even with values reduced you'll never get close to 58.2. There's 183 - 187 seats in the GOL 737-800SFPs.

If they weren't supposed to fly full, then why not stick with the 737-700?

 

Lasse, some things to consider,

-Pax standart weight is complete with carryon, and varies from 70 to some 88 kilograms, depending on whether male, female, summer, winter, total average, airline, etc. However your figure of 80kgs is OK, provided no children (which is not unreasonable for a flight from Santos Dumont, I guess)

-Crew weight is a part of dry operating weigth. That is half a tonne down.

-It is very, very, very unlikely there would be 183 pieces of luggage on a flight with 183 passengers. Even on charter flights. On a flight between Sao Paolo and Rio de Janeiro, even 100 pieces is an overstatement. Lets say one tonne down. Now we are on 60 tonnes, and expecting a 100% load factor. Going just down to 90% loadfactor, which is still considered very, even exceptionally, good load by most airlines, and we arrive at 58.2

 

Now, with 166 passengers, you are still 20 passengers up from the 700, and at a lesser cost per pax for 800, plus you can use 800s bigger versatility.

Many thanks to all of you!

 

Based on your guidance these are may new calculations:

 

 

Blue numbers are the settings for the calculation. The "boxed" numbers are for the FS actions menu, when I load the aircraft.

 

With reduced luggage per PAX (0,6 bags), with reduced avg. luggage weight, with reduced reserve fuel, and with a 87,4% load factor; it seems I'm just going to make it.

 

There's a significant limitation in the need to carry fuel for an alternate destination. Does anyone know what the requirements are for that (for that specific route)? If weather is good and not changing, would it be okay to plan for the nearest airport as alternative? It's only 10NM away (SBGL). It would give me another 1,000kg to play with.

 

Oh, and I didn't include APU fuel usage. I'd expect to use 5 minutes APU at both departure and arrival gate, but I can't find the numbers for APU fuel usage. How much fuel would the APU burn per minute?

 

thanks again

 

//Lasse

Now, with 166 passengers, you are still 20 passengers up from the 700, and at a lesser cost per pax for 800, plus you can use 800s bigger versatility.

 

Correct, that's the point. You don't need to go full load. If you always book around 160 souls (don't know, just a stupid guess) per leg on the 800, I think you got your break-even.

I've never flew (as a passenger) this route here in Brazil, so I can't comment about the load factor, but I know this is perhaps the most profitable route in our country. There are more than 80 daily scheduled flights from SBSP to SBRJ and back.

There's a significant limitation in the need to carry fuel for an alternate destination. Does anyone know what the requirements are for that (for that specific route)? If weather is good and not changing, would it be okay to plan for the nearest airport as alternative? It's only 10NM away (SBGL). It would give me another 1,000kg to play with.

 

This depends on company policy (and regulatory background). It seems fully reasonable, to me, to only include fuel for Galeao, if the weather is good. Of course you never know when there might be a disabled plane on the runway, or bomb scare, or whatever, but generally in those cases, you will be able to go to Galeao, or, divert en-route. It is a tad more difficult when the weather is not good, you do have to consider more factors.

 

Oh, and I didn't include APU fuel usage. I'd expect to use 5 minutes APU at both departure and arrival gate, but I can't find the numbers for APU fuel usage. How much fuel would the APU burn per minute?

 

APU fuel usage is factored in departure taxi fuel. We use taxi fuel of 200kgs, but we are a small airport here. On a big airport, if more taxi is expected, adjust.

Taxi fuel, nor APU fuel, is not considered on arrival side. Under normal circumstances, you will land with sufficient reserves to cover this. And even if the worst case happens and you do run out after landing, they can tow you away. You would have a different problem then - why did you not go elsewhere? Anyway the point is, no need to add any fuel beyond normal reserves.

 

Anyway APU on 737 did like 100kg/hour IIRC, depending on what you used from it (gen, one pack, two packs)

Guys, this is good information. Thank you very much. I flew the route both ways yesterday adhering to the weight limits. Everything worked out fine. Vref was a bit lower than it used to be, and the landing roll was i bit shorter.

 

It's really a great route to fly. Challenging landings, cielings in the SIDs, nice landscape, and good scenery coverage with AES support. Plus it's still daylight in Brazil when I have time for flight simulating here in Copenhagen (with real weather I don't like night temperatures in daylight).

 

If weather in Rio is good, I can carry up to 170 PAX and still be within limits. If weather is close to minimums I'm down to 155-160. It must be quite hard to manage and book passengers on that route. But anyway: that's not the pilots headache :-)

 

I used to play Airwaysim (online airline management game), where i operated out of SBSP. In the game at least the SBRJ route was in deed very profitable.

 

Thanks again for all your answers.

 

//Lasse

http://www.flightsimsoft.com/topcat/

 

It is enough i guess !

 

Marcos

Folks,

 

do you think the FMC calculates V1 dependent on the runway length?

I am not sure.

Especially at SBRJ V1 must be pretty low around 100kts...

I dont thinks so, but cant be sure.

http://www.flightsimsoft.com/topcat/

 

It is enough i guess !

 

Marcos

 

TOPCAT can't handle the SFP. It's just going to tell you that the runway is too short. And it's not going to calculate the correct performance. But we might hope for that feature in PFPX http://www.flightsimsoft.com/pfpx/

 

 

 

Folks,

 

do you think the FMC calculates V1 dependent on the runway length?

I am not sure.

Especially at SBRJ V1 must be pretty low around 100kts...

 

It does not, and is not supposed to.

 

Cheers

/Lasse

It does not, and is not supposed to.

 

Surprising...

Are VR and V2 calculations also not real, but a PMDG courtesy?