Intersection take offs with Encore's Q400

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Donald
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Re: Intersection take offs with Encore's Q400

Post by Donald »

Can anyone provide an accident report where the use of a properly planned and executed intersection takeoff combined with a high speed failure to result in a crash/runway over run?
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ahramin
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Re: Intersection take offs with Encore's Q400

Post by ahramin »

Exactly what I was wondering Donald.
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Oxi
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Re: Intersection take offs with Encore's Q400

Post by Oxi »

What would have happened if they did take an intersection
http://avherald.com/h?article=49f37b96&opt=0
https://www.youtube.com/watch?v=jyshWtu8zZM
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fish4life
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Re: Intersection take offs with Encore's Q400

Post by fish4life »

Well Oxi to play devils advocate if they took an intersection departure they would have one less potential crossing point therefore reducing the risk of a collision with another plane
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RB211
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Re: Intersection take offs with Encore's Q400

Post by RB211 »

I guess we have to define 'airmanship'.

I think that can depend a bit on the type of flying involved. A private pilot can have different priorities and considerations than an airline pilot let's say.

As an airline pilot I am tasked with operating in a safe and efficient manner. It is part of the job to assess the situation of the day and make a decision that is both safe and efficient.

That decision may be to depart from an intersection rather than full length. Nothing wrong with it if it is done with due consideration and utilising proper performance data.

We elect intersection departures in the 777 at times. At some airports not doing so will possibly result in unnecessary delays. The Boeing OPT must, of course, have the intersection selectable from the menu to do so.

As mentioned previously, the safest option would be to never go flying but until I find an airline that will still pay me for that, I will make the best decisions I can with the information available.
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complexintentions
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Re: Intersection take offs with Encore's Q400

Post by complexintentions »

mbav8r wrote:You're correct, the frost was off base and geared more towards the unstable approach and where do you draw the line for shortcuts.
Yes I use reduced thrust, that's a company policy and in the COM/AOM and all the takeoff data is calculated using reduced thrust, full length or intersection. It is not company policy to depart from intersections, that's someone choosing to do something that is allowed but not the safest thing to do, not unsafe. My point was simply that leaving that much runway behind you is not displaying airmanship, I don't think the are reckless and irresponsible.
You didn't answer my question, why are you doing it?
Also I would like to say, I've done it in the past and honestly the only reason is on time performance, is that a good enough reason because I think we can agree, the safest thing is full length.
Actually, no. I categorically disagree, probably because your statement is totally wrong: if the performance figures will allow an intersection takeoff it is mathematically exactly as safe as using the full length. That's, um, why they publish such figures. Which are conservative. Yes, there may be other variables that make taking the full length the better choice. But I reject categorical statements like "full length is always the safest thing". Nonsense. You're just unnecessarily throwing tools out of your toolbox with such narrow thinking.
Balanced field only works if you perform at the required performance levels.
Counting on extra runway to compensate for poor technique on a reject is not my idea of "good airmanship".

My idea of good airmanship includes exercising strong risk management, balancing it with operational considerations. If an intersection takeoff will allow us to avoid a delay and can be safely accomplished with the proper performance figures, it is poor airmanship to sit there waiting for the full length.

Trying to maintain on-time performance within the bounds of safety is very much a component of airmanship. Of course safety is the priority but trying to suggest that a properly planned intersection takeoff is unsafe is a total non sequitur.

But I do always enjoy listening to pilots judging other pilots operating aircraft they themselves don't fly. :roll:
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Tanker299
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Re: Intersection take offs with Encore's Q400

Post by Tanker299 »

Donald and complex you hit the nail on the head.

If your the pilot who needs full length on a day with no risk of surface or runway contamination please tell me what you are going to do with that runway in front of you after V1 or rotate? Even better what are you going to do with it after you put in the turn at 400-500 feet only half way down the runway?
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goingnowherefast
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Re: Intersection take offs with Encore's Q400

Post by goingnowherefast »

Use it to slow down more gently. It's easier on the tires and brakes, plus you don't need your passengers to be hanging off their seat belts in the event of a reject. Maybe use balanced field +25%, and anything beyond that is unnecessary?

Runway behind you is useless, but so is runway ahead of you after after coasting to a stop from V1.
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atphat
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Re: Intersection take offs with Encore's Q400

Post by atphat »

Rejected takeoffs are not, or meant to ever be gentle. Passenger comfort is not what you should be thinking of during a RTO.
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complexintentions
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Re: Intersection take offs with Encore's Q400

Post by complexintentions »

I agree with what I think you're trying to say atphat, but I would add that you're referring to a reject in the high speed regime i.e. after 80 knots and before V1. And you're correct, a high-speed reject is critical, the priority is definitely not to "slow down more gently". Or you may find yourself gently taxiing off the end of the runway, depending on how close to V1 you were when you initiated the reject. :mrgreen:

Obviously if you reject at low speed you may not need to brake hard enough to hang the pax in their belts. You might just retard the thrust levers.

But neither a high or low speed reject requires some arbitrary extra distance beyond the performance figures.
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brooks
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Re: Intersection take offs with Encore's Q400

Post by brooks »

This thread is so dumb...
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complexintentions
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Re: Intersection take offs with Encore's Q400

Post by complexintentions »

Well from your comment you certainly seem qualified on the "dumb", thanks for contributing! :mrgreen:
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mbav8r
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Re: Intersection take offs with Encore's Q400

Post by mbav8r »

Complexintentions, we're not talking about taking a delay, it's about turning a very long runway into a balanced field for saving a minute or two, very rarely is there a line up for departure in YWG! Like I said, it's not unsafe, it's not as safe. I also happen to know how the Q performs.
Couple things, a high speed max braking reject on a loaded RJ will have the brake temps rise to white after the reject and even red in a warmer climate, so if you know you have room you can avoid this.
Maybe a poor analogy but if you have enough money in your account to pay the bills, that's all you need, if you have some left over after the bills are paid are you more or less comfortable?
What's better, more fuel than you need or exactly the right amount?
To be clear, just today tower had us taxi to an intersection for departure, we sent for a new TLR as my default was full length, I think we established this but anyhow, numbers worked and I looked at the line up for the full length and opted for the intersection, see I was able to work outside the box.
BTW, your math is out, you're assumption is at V1 you're going flying, there are other variables that could cause a reject after V1 and I for one will be happy to have extra runway if it ever happens.
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Lateralus
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Re: Intersection take offs with Encore's Q400

Post by Lateralus »

brooks wrote:This thread is so dumb...
Agreed.
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Eric Janson
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Re: Intersection take offs with Encore's Q400

Post by Eric Janson »

mbav8r wrote:BTW, your math is out, you're assumption is at V1 you're going flying, there are other variables that could cause a reject after V1 and I for one will be happy to have extra runway if it ever happens.
You do not reject a take-off after V1.

V1 is the speed at which the take-off must be continued unless the stopping maneuver has already been initiated.
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Re: Intersection take offs with Encore's Q400

Post by Yycaviator »

mbav8r wrote:
Maxpwr wrote:This is the dumbest conversation I've seen in a while. So we're gonna fret because they "leave half the runway behind them", when that runway is 11000' long?! If you had any idea what he Q400 can do you'd be having a laugh along with me and everyone else who flew into and out of the Island with it. I'll say it again, if the Aerodata shows it works then what's the problem? Having said that if there was any contamination in the runway then I wouldn't choose such an aggressive intersection. That's where airmanship comes in. Airmanship does NOT mean taxi your 172 to the end of a 11000' runway just in case. Ridiculous.
I've been offered S intersection 35R in YYC many times and turned it down every time, is 12,000 feet enough, sure but imagine a scenario where you have a control malfunction occur at V1 and you attempt to rotate but can't, I'll sure be happy to have that extra 2000 feet at that point. Plan for the worst, hope for the best.
Do you know why S is where it is?

S was placed to keep the runway out of the 29 arrival terp (or whatever the fancy name is for protected airspace design is). So at night/mornings/weekends when they are landing 29, and departing 35R, if you take full length, the tail of your plane is effectively shutting down arrivals on 29 because it intrudes the protected zone.

So your co-workers and friends at other airlines thank you for making a silly point and arguing over a standard YYC procedure. Perhaps you can find some time to read the FAA/NTSB reports on rejects after V1 on your extended taxi next time.

The numbers work, the numbers work. Thunder Bay was NOTAMED down to 5,000 feet all summer. Which is much shorter than a 35L intersection takeoff.. So are we saying Westjet should have suspended ops into Thunder Bay this summer?
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goingnowherefast
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Re: Intersection take offs with Encore's Q400

Post by goingnowherefast »

I bet these guys appreciated having extra runway in front of them. They rejected well after V1.

http://www.rcaf-arc.forces.gc.ca/en/fli ... t/hky1dmyy

That being said, they also had 1500' in front of them when they stopped.
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PositiveRate27
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Re: Intersection take offs with Encore's Q400

Post by PositiveRate27 »

I fly the Q400 and I'm very aware of what it's capable of. I'm also realistic about what the Mark-1 human is capable of. (or incapable in some instances)

Qatar departed from the T1 intersection on rwy 29 in Miami and struck runway approach lights at the far end due to crew erroneously entering takeoff data. Had they used full length they would have had adequate takeoff distance, regardless of what they had typed in. Now imagine if they had had to do an RTO at v1 that night.

If everything goes exactly as it should, intersection takeoffs work just fine. In many circumstances it would be silly to turn down an intersection departure such as 35R from S in YYC or 08R from L4 in YVR.

The unfortunate fact of life is that things don't always go as planned. Humans make errors. Perhaps a crew enters data in incorrectly. Perhaps they don't react as they should at critical moments. Perhaps the airplane has such a catastrophic failure it's incapable of flight after v1. I've personally seen ACARS print out erroneous data. I then resent for a new TLR with the exact same parameters and received completely different speeds and distance required.

At the end of the day, it's your aircraft and your decision to take an intersection. Im happy to take intersections, but I won't choose to ever leave half the runway behind me simply to save a couple minutes, especially since I'll probably have to wait 5 minutes for a marshal when we arrive anyway...
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Re: Intersection take offs with Encore's Q400

Post by mbav8r »

This is getting a little ridiculous at this point, my preference is full length, more runway good, less runway bad. I have said I'm not rigid in this, if offered I won't take it nor will I ask for one to save a few bucks. If I have to because of terps or some other reason I will.
Due respect, Eric, if the plane won't fly at V1 are you just going to plod along off the end of the runway, seriously. V1 is extremely important on a balanced field and I understand that I have no way of knowing exactly how much extra runway I have but I will have a cushion, call it granny runway if it helps you sleep better.
Incident: Openskies B752 at Paris on Sep 20th 2010, rejected takeoff because of wrong flap setting
The airline reported, the takeoff was rejected at high speed due to an inconsistency between what the crew expected and got to see on their instruments. The airplane slowed safely and vacated the runway, the aircraft received minor damage to tyres and wheels consistent with a rejected takeoff at high speed.

Do you think this was a reject after V1? Very likely in my opinion, I'm just saying if a mistake is made and the plane won't fly, I won't be the guy justifying why I used an intersection instead of full length.
I did find some examples of a reject past V1 due to control issues and could have turned out differently had the crew opted for a balanced field instead of full length.
You guys do what you want!
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Re: Intersection take offs with Encore's Q400

Post by complexintentions »

As Eric said, you do not reject a takeoff after V1. The RCAF crew did, and got away with it. That does not in any way justify using extra field length to reject after V1.

The whole point of V1 is to remove the need to make a decision at high speed. That's why it's also called "decision speed". The whole procedure is designed to stop the machine before V1, and take a problem airborne after V1. That's it, that's all. In a large a/c at V1 you're covering almost 300ft of runway every second. At that point the last thing you should be doing is an assessment if you can still stop. These guys were able to do what they did being in a slower C130 and had a successful outcome. But I shudder to think that it's being held up as an example of a good idea or a valid defence of taking full length. A fire is absolutely a dire situation, sure. It still doesn't justify rejecting after V1. Yycaviator is right, read the reports on rejects after V1. Far, far more often there is a terrible outcome to what could have been handled safely and routinely in the air.

I wasn't going to post again in this thread. A couple have commented that it's "dumb". Due to the laziness of such comments it's not really possible to tell what they're referring to. But I'm amazed by how many posters seem to genuinely think that full-length takeoffs are "always safer", and apparently the reasoning is, since you then have more chances of stopping if you put in wrong performance figures, mishandle the reject, or decide to initiate it after V1. With that mentality, I hope that if I'm a pax behind a crew that is already considering not following their own procedures that they DO take the full length!

Consider me "dumbstruck". :shock:
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