Sterile area

[pdjpeter]

hi all, ive just had a lecture at air cadets on airfeilds saying that at the end of the runway (either end) (arrowed ponint befoe threshold)
theres apoint called the sterile area where aircraft are not allowed to stop movement but passed the runway they are
my friend is argueing against this
has anyone hered of a sterile area of a runway

[AeroJim]

never heard of that, that to me doesnt even make sense, the displacement threshold is used usually for taxi and take-off but not landings
as far as the FAR describes it in part 91, but the 'sterile area' makes absolutely no sense, i've been to multiple runways in my time as a
student and in the displaced threshold there has never been a section of a sterile area or markings that could lead me to believe that, so
if maybe this is for miliary? But no, never heard of it and tried to google it and faa.gov it and nothin came up.

[Tanz]

Never heard about that in the military....& i just wonder...why "sterile"?? It counts in your TODA/ASDA calculations...!
But as Aerojim said, never land on it...it doesn't have the same weight load limit.

Cheers

[Airliner]

aircraft are not allowed to stop movement but passed the runway they are

This statement confuses me a bit. However, are you refering to the displaced threshold or the overrun area? The overrun has arrows,
though they are more like chevrons. But then, there's nowhere else to go if you use it so you would have to basically sit on one spot while
turning the aircraft around to get out onto the taxiway.

[pdjpeter]

the part i'm saying is before the threshold (its an arrowed area) where when taxing you cannot stop in case of an emergancy landing



Post Edited ( 03-22-06 19:54 )

[AeroJim]

displaced threshold, no such thing as sterile area, in case of an emergency landing these acft would have to make a distress call in
such event no plane would even get on the active.

[Jetflyer]

That's a load of rubbish. A runway has a displaced threshold particularly if there are buildings or trees or object near the end, so that the
touchdown zone area is further down the runway meaning the aircraft has better seperation from the objects. However, an aircraft can takeoff from the
beginning of the displaced threshold, and if it's waiting for another plane to do its takeoff roll it will be told to taxi into position and hold.
That will obviously require it to be waiting at the end of the runway, not moving on the displaced threashold, until the plane ahead is handed of to
departure frequency. Obviously, that means the plane is sterile til its cleared for takeoff. So the idea of a displaced threshold area being sterile
is rubbish.

[KenG]

While not a sterile area I have heard that some HEAVY airplanes may not stop on the overrun at some airports due to the PCN not being high enough.
Provide the ICAO of the airport in question and I will check my Jepp references to see if this is the case.

[pdjpeter]

my warrant officer didnt put it down to one air base (it was a lecture on airfields) the air field in question was a main instrument runway (like an
airport)

[Airliner]

Well said Jetflyer. I would further clarify that the threshold is a reference for landing only - the takeoff "point" if you will is anywhere from
where the overrun meets the runway end. SAN has a fairly long displaced threshold in order for aircraft to clear parking structures on
approach. However, the displacement area can be and is used for the takeoff roll. I have no idea what this guy was talking about -
sterile? As far as I understand it, the entire airside is concidered sterile, compared to landside - with security as the transition. That's
obviously not what he was talking about though.

"when taxing you cannot stop in case of an emergancy landing"

This still makes no sense to me. Cannot stop in case of - what is that? Like AeroJim said, you wouldn't even be in the vicinity of an
aircraft making an emergency landing. Or are you saying that if YOU were making an emergency landing, YOU cannot stop in this area?
That's still a little vague. Do you have his exact words?

[pdjpeter]

he was on the projector it was a black n white picture of a Main runway he said (exactly) "this part of the runway *points to arrowed threshold part*
is called sterile area u cannt stop on this bit when taxing"

[Airliner]

Wow, that's bizarre. Never heard that one before. How long has he been off his meds? KIDDING!

[olseric]

The only thing I can think of is that it is NOT a displaced threshold and is merely a safety overrun.

Was there a diagram and if so, was the area covered with white arrows or yellow chevrons?

[pdjpeter]

yes there was a diagram and from what i remember (which it worrying because i got an exam on it) it was a lined area he said this is sterile area as
well as the threshold

[KenG]

Everything you need to know about airport markings and signs is located in the AIM: http://www.faa.gov/ATpubs/AIM/Chap2/aim0...#NX732ROBE

Well maybe not everything, but it is a great reference. The only area of a runway where you shall not stop in the blast pad. That is because you
should not be taxing there either. The other area you may not wish to stop on is the taxiway of relocated threshold. In the AIM I am talking figure
2-3-4. My reason for this is what happens if a pilot drags one in and your aircraft is sitting on the taxiway prior to the runway. In a case of the
runway as shown in figure 2-3-4, for safety I would stop at the intersection between the taxiway and the runway and request my takeoff from tower at
that point. Once cleared I would taxi without delay to the threshold and then conduct my takeoff roll. If there was a hold short line I would, of
course, stop there unless it was past the intersection. This is my technique not a procedure.