What is midpoint, RVR, and rollout?

Question

What do those three terms specifically mean? I hear them on occasion from listening to JFK tower, especially when there are low ceilings, fog, rain... I would think they would have to do with ILS approach, but am not sure, could anyone explain these three terms in detail to me please?

Answer 1

These terms do have to do with the instrument approaches. When the tower tells us what the RVR for a particular runway is they are telling us the visibility in feet. The RVR equipment is located alongside the runway at certain points. There are three main points, Touchdown, Mid-Point, and Rollout. These are pretty self explanatory as to where they are located. On an instrument approach, there are certain visibility requirements that must be met in order for us to commence the approach and continue to a landing. These visibility values are also needed to be known for takeoff. Generally, the minimum takeoff minimums we need are 600 RVR. That is pretty low visibility. When we have that low of a vis we will do a static takeoff where we hold the brakes while advancing the thrust levers. This allows us to check the instruments while stationary and then allows us to keep our eyes outside while rolling down the runway. All for safety.

Answer 2

RVR runway visual range
MIDPOINT position of the measuring equipment of the rvr in the middle of the runway /one of the three main positions -touchdown, midpoint, stopend/

ROLLOUT is generally the term of introducing a new aircraft. related to the other terms, this is probably the RVR measuring position at the furthest available taxiway.

simple, isn't it?

RVR limits the operability of the airbase. Related to the ILS approaches it differentiates the three ILS categories, with the category III having three subcategories related to the ground movement non visual aids.

RVR simply means how far you can see from the specified measuring point along the runway in meters or in feet/ units sensitive/.

these measurements are boradcasted through the ATIS information service, and just in case thez are transmitted to the arriving/departing crews with the phrase "check your minima" which means that airbase is operable, but the crew may not perform a specific approach due to the low visibility.

RVR is closely related to the LVP low visibility procedures, which restrict the airflow and have specific demands towards the crew and atc.

Answer 3

Midpoint and RVR are different for every runway. If you enter just RVR in your search engine you will get much better information for a specific airport than I can describe here. Rollout is the transition from ground travel to actual flight, i.e., when the aircraft leaves the ground and can go gear up.

There is no actual specific data for midpoint and RVR, since they vary from runway to runway. Also from aircraft type to aircraft type. A 747 is going to have a different midpoint and RVR than say, a Lear jet. Very different.

It is more important in bad weather to know the midpoint and RVR on a large passenger plane than it is to know it on a small aircraft. You don't want to touch down without enough runway to stop on! You also don't want to continue to accelerate in a takeoff roll if you don't have enough runway to take off from! In the case of JFK, you end up on the parkway after you go through the fence.

I worked at JFK (In the Pan Am terminal, back when they were still in business.) and the tower guys were always open to questions. Now with 9/11 protocal in progress, I'm not sure if they would be so open. But I got a tour of the tower just by asking. Give them a call. See if you can get a look and a listen. It is really amazing that you can't see your hand in front of you face outside, and these huge birds are landing dead on target.

By the way, if you know what ILS is you are halfway, or better, to knowing the rest of the terms. Personal favorite plane is the AT-6-A. Worked on 'em, and got a ride in one. A blast! I really would have liked a ride in an F-104, but it's not a two seater. I'd settle for an F-4 ride. As long as the pilot didn't do any strange stuff.

Well, seems I peed off a bunch of know nothing people. 5 thumb downs. Sorry to steal your thunder people, but I know my stuff. Ran out of dough just short of getting my VFR license for single engine light/sport aircraft. And I'm sure I remember enough to handle a twin. Do YOU know what to do when you lose one engine on takeoff? I do. Probably well enought to put it on the ground someplace safe, and not in a house. Do your homework before you drop a thumb. And don't try to contact me. I blocked you all! (I had to. I'm allergic to stupidity.)

Answer 4

I think you mean touchdown, midpoint, and rollout RVR.

Answer 5

they vary for different areas of the different runways
good luck mate :)