dnunes

Landing Data

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I have now progressed in flying the 777. I think I am missing something: with the TOPER Calculator I am able to introduce weather data to calculate the take off conditions. But what about the landing? I do not see how to introduce weather data to calculate the landing approach speed (VREF). What am I missing?

Regards,

Domingos

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6 minutes ago, dnunes said:

What am I missing?

That would be a question for the people who made TOPER.

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VREF is based on weight of the aircraft and not on weather. It is usually 1.3 times the stall speed for the configuration. Weather does not play into when an aircraft will stall, so there is no need. The ref speeds the FMS will provide are the correct ones.

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Thanks Kyle for your reply. TOPER provides data for takeoff, not landing. For the Airbus I have a similar tool to calculate the takeoff data, For the landing I introduce in the FMC the weather data (QNH, wind, temp) to calculate Vref. Maybe that for the bigger 777 weather data is not relevant.

Regards,

Domingos

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Thanks Nick for your reply. My previous reply to Kyle is in line with your information. It is a long time since I stopped flying the iFly737 but I think it also required weather input for then landing.

Regards,

Domingos

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5 minutes ago, dnunes said:

Thanks Kyle for your reply. TOPER provides data for takeoff, not landing. For the Airbus I have a similar tool to calculate the takeoff data, For the landing I introduce in the FMC the weather data (QNH, wind, temp) to calculate Vref. Maybe that for the bigger 777 weather data is not relevant.

Vref should always be the same, to my knowledge, but if the software is calculating rollout, and other distance-based info, that would be affected by wind at the very least.

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Thanks Kyle for your reply. l would expect that, as it happens with the Airbus, Vref would depend on the weight of the aircraft at landing, as well on with weather conditions: wind speed and direction, temperature... Isn't this always the case with any aircraft?

Regards,

Domingos Nunes

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5 hours ago, scandinavian13 said:

Vref should always be the same, to my knowledge, but if the software is calculating rollout, and other distance-based info, that would be affected by wind at the very least.

altitude is changing a little VREF but by 1 or 2 knots at max ...

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Posted (edited)
55 minutes ago, dnunes said:

Thanks Kyle for your reply. l would expect that, as it happens with the Airbus, Vref would depend on the weight of the aircraft at landing, as well on with weather conditions: wind speed and direction, temperature... Isn't this always the case with any aircraft?

Regards,

Domingos Nunes

On the 777, Vref is only weight dependent.

Actually it is the same as Airbus Vref = Vls on the landing distance calculation guide in the QRH, but on the airbus the amount of headwind component of greater than 15kts will change a the approach correction which increases the to above 5 kts. And as you have already know the standard airbus Vapp is Vls + approach correction which is quite often Vls + 5 just like the 777.

 

on the 777, life is much easier. Wind never changes the Vapp which is always Vref 30 or 25 or 20 (for eng out) + 5 kts, unless the wx condition is necessary for the pilots to bug up more up to Vref + 20kts. But the books says the A/T is react fast enough in gusty condition even without any bug up.

 

in general, on the 777 wind only affects the landing distance but not the Approach speed. 

 

Elevation of an airport may be significantly affects the landing distance. Low QNH has similar effect as landing at an airport with some elevation but never have a significant effect. Temperature is usually not a big factor. 

 

 

 

 

Edited by Driverab330
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1 hour ago, Driverab330 said:

on the 777, life is much easier.

The AOA never lies.  Although I set my approach speeds in the FMC, I fly the approach using the AOA.  

I started using the AOA when flying in the military, and it carried over into my civilian and commercial career. 

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2 hours ago, Driverab330 said:

On the 777, Vref is only weight dependent.

Actually it is the same as Airbus Vref = Vls on the landing distance calculation guide in the QRH, but on the airbus the amount of headwind component of greater than 15kts will change a the approach correction which increases the to above 5 kts. And as you have already know the standard airbus Vapp is Vls + approach correction which is quite often Vls + 5 just like the 777.

 

on the 777, life is much easier. Wind never changes the Vapp which is always Vref 30 or 25 or 20 (for eng out) + 5 kts, unless the wx condition is necessary for the pilots to bug up more up to Vref + 20kts. But the books says the A/T is react fast enough in gusty condition even without any bug up.

 

in general, on the 777 wind only affects the landing distance but not the Approach speed. 

 

Elevation of an airport may be significantly affects the landing distance. Low QNH has similar effect as landing at an airport with some elevation but never have a significant effect. Temperature is usually not a big factor. 

 

 

 

 

VREF for the LR is affected by pressure altitude.

 

at 240t the vref30 is 143 knots at sea level at 4000` it will be 144 knots. taken from QRH ...

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1 hour ago, phil747fan said:

VREF for the LR is affected by pressure altitude.

 

at 240t the vref30 is 143 knots at sea level at 4000` it will be 144 knots. taken from QRH ...

Thx for the info, I have never have the privilege to fly the 772LR in real life which I would love to.

 

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1 hour ago, phil747fan said:

VREF for the LR is affected by pressure altitude.

 

at 240t the vref30 is 143 knots at sea level at 4000` it will be 144 knots. taken from QRH ...

Do you think that is more accurate than the data presented by the AOA?

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4 hours ago, Bluestar said:

Do you think that is more accurate than the data presented by the AOA?

Here is my take on it. Flying by AOA is a good thing, however, in the situation of the 200LR, AOA would not matter. The 200LR has varying REF speeds to handle VMCA in the event of an engine failure during the GA phase of flight. Boeing wants you to have the extra speed to give you a larger safety margin because of this. AOA would not matter in this case as AOA will not tell you when you have VMCA'd the aircraft. 

6 hours ago, phil747fan said:

VREF for the LR is affected by pressure altitude.

 

at 240t the vref30 is 143 knots at sea level at 4000` it will be 144 knots. taken from QRH ...

You are correct. It is one of the rare aircraft where that is the case. Due to the shorter fuselage of the 200LR compared to the 300ER, the additional speed is needed for control ability reasons. A higher PA will result in less air moving over the wings at a given time, requiring a higher speed to be able to handle the asymmetric thrust in the event of an engine failure during a GA situation.

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10 hours ago, Bluestar said:

The AOA never lies.  Although I set my approach speeds in the FMC, I fly the approach using the AOA.  

I started using the AOA when flying in the military, and it carried over into my civilian and commercial career. 

Exactly. I've found a lot of the military guys I've flown with fly the AoA more than the speed. Is an AoA gauge pretty common equipage in that area? I know a lot of the fighters have an AoA gauge (or an over/under/on indicator, really) by the HUD somewhere, but is that something that they teach/practice pretty consistently across the board?

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4 hours ago, scandinavian13 said:

Exactly. I've found a lot of the military guys I've flown with fly the AoA more than the speed. Is an AoA gauge pretty common equipage in that area? I know a lot of the fighters have an AoA gauge (or an over/under/on indicator, really) by the HUD somewhere, but is that something that they teach/practice pretty consistently across the board?

I can't answer to modern fighters, but flying a F-106 or F-4 the AoA was very important instrument.  It's about the only thing that kept you above stall on approach.

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6 hours ago, scandinavian13 said:

is that something that they teach/practice pretty consistently across the board?

It starts with the T-37 and T-38.  Also on the KC-135.  My AF fighter buddies tell me it's on the A-10 and the F-16.  The Navy guys I know say it was on all their airplanes including the props.  The carrier guys tell me they could not imagine coming on the "boat" with out the AOA.  

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10 hours ago, 19dcavscout said:

Here is my take on it. Flying by AOA is a good thing, however, in the situation of the 200LR, AOA would not matter.

I don't know about this, but I'm going to be eating burgers this weekend with one of my hockey buddies who flew the 200LR for several years.  I will ask.  He is a former military fighter guy and a big believer in the AOA.

  

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i do not fly the LR but here is something to read about the AOA in a civilian aircraft:

 

http://www.boeing.com/commercial/aeromagazine/aero_12/attack_story.html

 

or the pdf

http://www.boeing.com/commercial/aeromagazine/aero_12/aoa.pdf

 

i am aware of AA and DL for the fitting of aoa on a 777 so it will be very interesting to read what the pilots using will say about it on a commercial plane.

 

btw the 200er is affected also by the vref and pressure altitude ... under JAA and FAA certifications for the GE90-94.

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i may add even if not the right part of the forum. the 747-400 had the same issue and you needed to add +1 knot by 3000 feet for VREF30 and 25 and it was with at least operator. data were given starting at sea level pressure. 

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8 hours ago, Bluestar said:

I don't know about this, but I'm going to be eating burgers this weekend with one of my hockey buddies who flew the 200LR for several years.  I will ask.  He is a former military fighter guy and a big believer in the AOA.

  

An A0A indicator provide very useful info. However the only time where I did an approach solely rely on AOA information is when using the BUSS (backup speed scale) on the A330. It is indeed a very useful feature in the event of unreliable airspeed indication.

 

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On 6/7/2018 at 9:14 PM, scandinavian13 said:

Exactly. I've found a lot of the military guys I've flown with fly the AoA more than the speed. Is an AoA gauge pretty common equipage in that area? I know a lot of the fighters have an AoA gauge (or an over/under/on indicator, really) by the HUD somewhere, but is that something that they teach/practice pretty consistently across the board?

I am in the military and we don't fly with it at all. To be fair, the Army focuses on rotary wing flight, and even though I fly fixed wing, it is a lot harder to get people to start thinking like that. It doesn't help that our aircraft, at least the few that I have flown, are not equipped with them. I would love to have one in my aircraft, I am sure it could help the frankenstein of the aircraft I am currently flying. 

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3 hours ago, 19dcavscout said:

I am sure it could help the frankenstein of the aircraft I am currently flying.

LOL what are you flying Nick?  My guess is U-21A?  I've heard good and bad about the King Air 100s.

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11 hours ago, downscc said:

LOL what are you flying Nick?  My guess is U-21A?  I've heard good and bad about the King Air 100s.

RC-12X. King Air 200 body, Beech 1900 wings tail and landing gear, -67 engines, and a crap ton of antennas. It's definitely something else.

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11 hours ago, downscc said:

My guess is U-21A?

I liked the U-21 and my family has a C-90 that I really enjoy flying when they need the extra help.  But it's possible I could be confused since I flew "Charlie" models in SE Asia. ROFL.

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