3 minutes ago, Bobsk8 said:

But intersection takeoff will get you to V1 much sooner and V1 should be a much lower airspeed, I would think. 

Still well within acceptable safety margins for take-off, though.
These type of departures would be prohibited if they were not safe.

An intersection take-off is useful for ATC to increase the departure flow by placing one aircraft on the runway ahead of another that is lined-up behind. Or to get a lighter departing aircraft airborne before another heavier one can reach its hold short point much further down the same runway.
Additionally, it will save time (and thus fuel) for the airline if a flight doesn't need to taxi for a full-length departure.

4 minutes ago, F737MAX said:

Still well within acceptable safety margins for take-off, though.
These type of departures would be prohibited if they were not safe.

An intersection take-off is useful for ATC to increase the departure flow by placing one aircraft on the runway ahead of another that is lined-up behind. Or to get a lighter departing aircraft airborne before another heavier one can reach its hold short point much further down the same runway.
Additionally, it will save time (and thus fuel) for the airline if a flight doesn't need to taxi for a full-length departure.

Take Heathrow, Gatwick, Amsterdam even Copenhagen, Manchester all use Intersection departures a lot 

Edited February 25, 20233 yr by carlanthony24

1 hour ago, Bobsk8 said:

I never did an intersection takeoff. A good friend of mine who was a retired B 52 instructor and used to go flying with me, always told me to go to the end of the runway and I do the same in the sim.

Spent four years RAPCON and Tower at Minot AFB. Never once did I see a BUFF do an intersection departure. 😎

They had 13,300 ft if I recall and they needed it all on hot ND days when fully loaded with Ord. and Fuel.

-B

Edited February 25, 20233 yr by btacon

5 hours ago, Bobsk8 said:

The FMC in the 737 calculates takeoff and landing speeds already. I use Avliasoft EFB for all my charts, so that is something I would have no use for. 

And how do you calculate reduced thrust takeoffs? The fmc doesn’t do that. You have to manually put in an assumed temp. How do you get that number? Not through the fmc.

1 hour ago, Bobsk8 said:

But intersection takeoff will get you to V1 much sooner and V1 should be a much lower airspeed, I would think. 

How would it get you to V1 sooner? V1 is a speed. Not a point on the runway. 

2 hours ago, Stearmandriver said:

Intersection takeoffs are the norm at EWR, JFK, and ORD, to name just a few. 

I often listen to ORD and JFK tower controllers on the LiveATC app. At ORD, takeoffs on runway 28R are normally done from intersection N5, and at JFK, takeoffs on 31L are often done from intersection K or KE.

Just now, ahsmatt7 said:

How would it get you to V1 sooner? V1 is a speed. Not a point on the runway. 

Speed and distance are related to each other... If you start at 12000 feet runway you reach V1 at let's say 6000 feet left, if you start at 8000 feet you reach V1 at 2000 feet. In practice this will be mitigated by a lower V1 speed and higher thrust settings for intersection takeoffs, but still this means you'll have less margin to reject the takeoff in case of a serious issue, so - statistically spoken - more aircraft from intersections takeoffs will have to get airbone with an engine on fire than those from full runway takeoffs with an engine on fire.
So in a theoretical world without any traffic concerns or ATC procedures a full runway takeoff would be safest (and the most economic). But as others said, that's a moot discussion because in real life intersection takeoffs are commonplace.

19 minutes ago, Fiorentoni said:

Speed and distance are related to each other... If you start at 12000 feet runway you reach V1 at let's say 6000 feet left, if you start at 8000 feet you reach V1 at 2000 feet. In practice this will be mitigated by a lower V1 speed and higher thrust settings for intersection takeoffs, but still this means you'll have less margin to reject the takeoff in case of a serious issue, so - statistically spoken - more aircraft from intersections takeoffs will have to get airbone with an engine on fire than those from full runway takeoffs with an engine on fire.
So in a theoretical world without any traffic concerns or ATC procedures a full runway takeoff would be safest (and the most economic). But as others said, that's a moot discussion because in real life intersection takeoffs are commonplace.

Like you said, those distances are allllllll taken into account when a v1 SPEED is selected. But still, v1 isn’t a distance, it’s a speed. So to say an aircraft would reach v1 more quickly purely based off of an intersection is fundamentally wrong. Your math proves my point. 
 

I understand what you’re saying though. Your view point is more of a big picture understanding.

This EFB better be best in the industry, lol 🙄

2 hours ago, ahsmatt7 said:

Like you said, those distances are allllllll taken into account when a v1 SPEED is selected. But still, v1 isn’t a distance, it’s a speed. So to say an aircraft would reach v1 more quickly purely based off of an intersection is fundamentally wrong. Your math proves my point. 
 

I understand what you’re saying though. Your view point is more of a big picture understanding.

Correct me if I'm wrong, but what he means to say is "With a shorter runway, V1 is lower, and so there's a larger window where you are committed to taking off with an engine failure or fire."

Which is how I understand it and would agree semantics aside.

9 hours ago, DAD said:

Seems to work just fine with SU12beta, just sailing along from LOWI to EDDH. No parking brake issue, btw.

Your lucky, SU12beta broke mine.

33 minutes ago, WestAir said:

Correct me if I'm wrong, but what he means to say is "With a shorter runway, V1 is lower, and so there's a larger window where you are committed to taking off with an engine failure or fire."

Which is how I understand it and would agree semantics aside.

Yeah you’re right. The same goes with contaminated runways. 

4 hours ago, ahsmatt7 said:

How would it get you to V1 sooner? V1 is a speed. Not a point on the runway. 

V1 speed is the tool used by pilots of transport category jet aircraft to ensure adequate stopping distance remains if the pilot elects to stop the takeoff due to an engine failure, fire or other event which may limit the ability to safely fly. The key component of V1 is the balanced field length which is the distance to accelerate to V1 and then stop if necessary using max braking, engines at idle and spoilers deployed. If the Balanced Field Length computed is equal to runway available then the Takeoff Distance is said to be Field Length Limited. In some cases the computed balanced field length may exceed runway available and in such cases either the weight must be reduced, a different flap setting used or another longer runway used for takeoff.

To determine V1 the pressure altitude, temperature, runway length, runway slope, wind, condition of runway (dry, wet or icy) must be known and the aircraft takeoff weight and flap setting for takeoff. Above V1 the pilot must continue the takeoff or risk going off the end of runway attempting to stop.

14 hours ago, jarmstro said:

I can. Hopefully I won't have to spend my time trawling though 500 menus and options on the FMC just to set Kgs instead of lbs. I STILL can't remember where the hell the setting is.

err  i  must be  missing  the  500th  menu,    reason  you  cant  find  the  settings its  in  the  501  menu 🙂

Edited February 26, 20233 yr by pete_auau

9 hours ago, Sonosusto said:

Yupper! 😁

And hopefully not with a "jammed" radar.. 😉