Displaced threshold question.

[Cat Driver]

Runway 34 in Nanaimo has a 1000 foot displaced threshold.

Can you legally land before the 1000 foot marks?

[iflyforpie]

Funny, I had the same thought about the one in Penticton today.

The guy who taught me taildragger used to land his Taylorcraft before the displaced on 34 and taxi off at Alpha, which entered the runway at the displaced threshold.

I think it is to ensure obstacle clearance for a standard approach (ie, using the ILS, PAPIs, etc); but many GA pilots like me do a steeper approach, so obstacle clearance isn't an issue.

Maybe it is just a suggestion, like off ramp and corner speeds on the highway.

No time to look at the regs, time to mow the lawn...

[Cat Driver]

The reason I am asking is because the question came up today watching airplanes land and almost every airplane flew to the displaced threshold markers before touching down.

Someone who is a high time pilot said it is illegal to touch down before the displaced threshold and that is why most everyone including the flying schools fly to the displaced threshold.

I can not find anything in the flight supplement that mentions that.

[Aeros]

Runway 34 in Nanaimo has a 1000 foot displaced threshold.

Can you legally land before the 1000 foot marks?

Yes. The AIM covers this case specifically in AGA 3.3 -- Displaced Runway Threshold.

When the portion of the runway before the displaced threshold is marked with displaced threshold arrows (see AGA 5.4.1), it is permissible to use that portion of the runway for taxiing, for takeoff and for the landing roll-out from the opposite direction. In addition, this displaced portion of the runway may be used for landing; however, it is the pilot’s responsibility to ensure that the descent path can be safely adjusted to clear all obstacles. When taking off from the end opposite to the displaced threshold, pilots should recognize the fact that there are obstacles present that penetrated above the approach slope to the physical end of the runway, which resulted in the threshold being displaced.

The emphasis is mine, but it is clearly OK, with the caveat that you are on your own to ensure obstacle clearance. (The threshold markings outlined in AGA 5.4.1 are both the permanent and temporary displacement markings.)

[Cat Driver]

Thanks, it has been a long time since I needed to read or know anything regarding the rules in Canada and was sure someone here could point me to the correct answer.

Now I have another question.

Seeing as there are no obstructions before the runway threshold why do almost all the airplanes fly over 1000 feet of usable runway before touching down, especially when training?

[Edelweiss air]

Thanks, it has been a long time since I needed to read or know anything regarding the rules in Canada and was sure someone here could point me to the correct answer.

Now I have another question.

Seeing as there are no obstructions before the runway threshold why do almost all the airplanes fly over 1000 feet of usable runway before touching down, especially when training?

Probably cause they don't know any better. I think it also depends on how the threshold is displaced. If it is displaced with chevrons that means it is a non-load bearing surface if it's with arrows then you can taxi or land on it. I guess that's more applicable to large aircraft though. Don't quote me on this.

[joco]

...
Now I have another question.

Seeing as there are no obstructions before the runway threshold why do almost all the airplanes fly over 1000 feet of usable runway before touching down, especially when training?

Would it be possible that the obstruction (ie trees, antenna, tower) was removed? Only a local pilot could shed some light on the history of the place.

[Cat Driver]

Would it be possible that the obstruction (ie trees, antenna, tower) was removed? Only a local pilot could shed some light on the history of the place.

I have been flying out of this airport for about thirty years and there has never been any obstruction on the approach to that runway that would prevent you from making a normal approach and touch down at the start of the runway.

When I operated a Cessna 185 on Whipline Amphibs I used to land and do a 180 before I got to the displaced threshold and taxi back to the end and exit, so I was just wondering why most everyone lands a thousand feet from the start of the runway.

You have to cut me some slack when asking these questions because I am from an era when we were taught to land at the start of the runway in small airplanes, it just seems weird to see them fly a thousand feet down a runway before they land.

[Cat Driver]

Cat, I flew a deck for a year, the second wire is too far from the round down!

Ahh yes Clunk but that was before they dumbed flying down to the lowest IQ and motor skills individuals in society.

In today's world being able to touch down on the airport and not run it through the far end fence is sufficient to get a license.

[joco]

[quote="Cat DriverYou have to cut me some slack ...[/quote]

CUT. Done.
Regarding the possible obstruction I see why Burlingotn Ont has it, there is the ravine and the tree patch that will rock and sink your a/c.

Without highjacking the post and out of curiosity, were there any displaced thresholds 30 years ago?

[Cat Driver]

Without highjacking the post and out of curiosity, were there any displaced thresholds 30 years ago?

No.

[Cat Driver]

There has to be lots of instructors here who use runway 34 at Nanaimo and maybe they can explain why so many fly down the runway to land...

For sure there are lots of training airplanes that do, and few that touch down before the displaced threshold.......a lot do float another thousand feet before touching down though.

[CD]

Curiously, the FAA AIM does not indicate that the landing aircraft can use the displaced portion of the runway on the approach:

2. Displaced Threshold. A displaced threshold is a threshold located at a point on the runway other than the designated beginning of the runway. Displacement of a threshold reduces the length of runway available for landings. The portion of runway behind a displaced threshold is available for takeoffs in either direction and landings from the opposite direction. A ten feet wide white threshold bar is located across the width of the runway at the displaced threshold. White arrows are located along the centerline in the area between the beginning of the runway and displaced threshold. White arrow heads are located across the width of the runway just prior to the threshold bar, as shown in FIG 2-3-4.

FAA AIM - Official Guide to Basic Flight Information and ATC Procedures; Chapter 2. Aeronautical Lighting and Other Airport Visual Aids; Section 3. Airport Marking Aids and Signs

I guess Canada needs to amend the TC AIM to prohibit this dangerous practice and get in step with the FAA, eh?

[Cat Driver]

I guess Canada needs to amend the TC AIM to prohibit this dangerous practice and get in step with the FAA, eh?

You have to admit I sometimes think of good issues to ponder.

I am waiting to see how this one goes.

[PanEuropean]

Seeing as there are no obstructions before the runway threshold why do almost all the airplanes fly over 1000 feet of usable runway before touching down, especially when training?

Hello Cat:

Unless the pilot has local knowledge about why the threshold was displaced, the most prudent and cautious thing to do is to fly over the displaced part at a steady, stabilized 3° descent and plan to touch down past the displacement.

There could be any number of reasons for the displacement. Some have to do with obstacle clearance, and the obstacle might not be a fixed obstacle - I have seen runways where the threshold is displaced in order to allow sufficient height when crossing a road or waterway that is perpendicular to the end of the runway. In other words, the obstacle might be a tall truck or a sailboat mast that is not present all the time.

Thresholds are also often displaced because the entire runway surface is not wide enough to meet regulatory criteria. For example, runways up to 3,999 feet in length must be a certain width, from 4,000 feet and up, they have to be wider. An operator who wants to provide more than 4,000 feet of TORA or TODA can displace the threshold in order to deem the runway to be 3,999 feet long, but still take advantage of the longer surface length as TORA or TODA.

Generally speaking, landing distance requirements are less restrictive than takeoff distance requirements (most especially when you are dealing with twin engine aircraft and accelerate-stop distances), so, there is no penalty attached to deeming your 5,500 foot long (but only 50 feet wide) piste to be 3,999 feet long with a 750 foot displacement at each end.

Michael

[laticsdave]

[quote="Cat Driver"]There has to be lots of instructors here who use runway 34 at Nanaimo and maybe they can explain why so many fly down the runway to land...quote]

I used to fly to CYCD a fair bit while instructing out of CYNJ a few years ago. I believe that the CFS used to state that the portion of the runway before the displaced threshold on 34 was available for take-off ONLY, ie no landing before the threshold. I don't think it states that anymore, so maybe pilots aren't landing "short" due to some sort of outdated, misplaced tradition?!

Haven't been to CYCD for over 12 months now, so I'm sort of out of the loop re recent changes in the lower mainland and the Island.

[iflyforpie]

When I was taught to fly, it was to aim for the 1000 foot makers. Of course, this was on a 7300' runway. Where I fly now, there are no 1000 foot markers and if there were they would be 1/3 the way down the runway. So now I simply aim for the end (or slightly in front of it if I am going for a short stop). I still get renters sometimes who ask me how on earth I can land on such a short (3000' ) strip in such a hot aircraft as a 172...

The reason I am asking is because the question came up today watching airplanes land and almost every airplane flew to the displaced threshold markers before touching down.

Maybe it is that 'wacky' Nanaimo circuit.

[Cat Driver]

For sure there are no obstructions on the approach to runway 34 that would prevent you from landing before the 1000 foot threshold.

I used to fly C117's that were based at Nanaimo and don't recall ever touching down more than about 100 feet from the start of the pavement and that was following the off set final approach procedures for the noise sensitive area in the CFS.

It just seems strange to me that most everyone wastes the first thousand feet of perfectly good runway to land on when they are flying small simple single engine airplanes.

[ahramin]

In Nanaimo the PAPIs for 34 are also displaced, so following them you will land past the displaced threshold. In addition there is a hill directly South of the runway. If you do the angled circuit found in the CFS you will pass beside the hill rather than over the top, but someone unfamiliar with this airport and its procedures might want to stick to the PAPIs. Certainly at night I would never use the runway portion before the displaced threshold. In the day I still don't use it because the 4000' left are four times what I need.

Many years ago an air cadet glider ended up in the trees on the hill short of 34.

[taylor498]

Thanks, it has been a long time since I needed to read or know anything regarding the rules in Canada and was sure someone here could point me to the correct answer.

Now I have another question.

Seeing as there are no obstructions before the runway threshold why do almost all the airplanes fly over 1000 feet of usable runway before touching down, especially when training?

Probably cause they don't know any better. I think it also depends on how the threshold is displaced. If it is displaced with chevrons that means it is a non-load bearing surface if it's with arrows then you can taxi or land on it. I guess that's more applicable to large aircraft though. Don't quote me on this.

Not so sure about this. AIM 5.4.1 - "Displaced Threshold Markings" says that arrows are permanent and chevrons are temporary.

http://www.tc.gc.ca/CivilAviation/publi ... .htm#5-4-1

Why would it be permissible to land on a permanently displaced threshold but a "chevroned" temporarily displaced threshold be non-load bearing? Are they planning on beefing it up when they move the threshold?

Perhaps you're thinking of a stop way?

[Topspin]

For sure there are no obstructions on the approach to runway 34 that would prevent you from landing before the 1000 foot threshold.

I used to fly C117's that were based at Nanaimo and don't recall ever touching down more than about 100 feet from the start of the pavement and that was following the off set final approach procedures for the noise sensitive area in the CFS.

It just seems strange to me that most everyone wastes the first thousand feet of perfectly good runway to land on when they are flying small simple single engine airplanes.

The Dog Leg Approach due to noise abatement +

From the CFS:

RWY 34: ...maintain 1200 ASL until over Ladysmith harbor...

I would guess they are trying to flatten out the final approach angle.

[light chop]

Maybe people are landing long to reduce the taxiing to the next available exit?

Have to be good at flying down most of the runway and plopping it on at any desired location when operating out of long runways, like YYC 16/34 to keep ATC happy.

[LousyFisherman]

Seeing as there are no obstructions before the runway threshold why do almost all the airplanes fly over 1000 feet of usable runway before touching down, especially when training?

As I low time pilot I would probably waste 1000 feet of runway because I may not be aware of all the little regulation details regarding use of a displaced threshold. The fact that you were unsure to begin with, there has been a discussion about arrows versus chevrons, implies that it is safer (from a regulatory point of view) <B>for me</B> to land past the markings.

Far more worrisome to me is why do so many small plane pilots land their C150/172 at the beginning of a 5000-7000 foot runway and then taxi for close on a mile to clear?????? Blocks the runway, hard on tires, hard on the engine.

Have to be good at flying down most of the runway and plopping it on at any desired location when operating out of long runways, like YYC 16/34 to keep ATC happy.

ROTFLMAO I do this all the time at Lethbridge (7000 ft, land in the last 2000) and Springbank (5000 ft, land 1500 ft along for a convenient taxiway) and I am not very good at flying, I need lots more practise!

LF

[Geko]

I learned @ YYJ. If you land before the displaced threshold markers on 02 or 13 while doing the short field landing on your PPL flight test, you'll be assessed a fail for that exercise. Now with an obvious lack of critical thinking aside I have no problem freely admitting that when I was a > 70 hour student I would probably do the same thing as the pilots in Naniamo.

[iflyforpie]

When I was taught to fly, it was to aim for the 1000 foot makers. Of course, this was on a 7300' runway.

Actually, now I remember this was only the case for landing on 15 (now 16) at YLW or for circuits on 33 (34). When we came in for a full stop, we would land by the second to last taxiway and exit at the end to save taxi time.