Why fly the centre line?

[bar shaker]

Following on from the other thread about the recent, sad, incident at Kemble, I have often wondered why we are taught to follow the centre line on climb out.

I am not familiar with Kemble, but assume that the pilot had no suitable EFATO options ahead, so he turned around.

If you are on the centre line, just over the hedge, with 2000m of runway behind you, its a sorely tempting option. At 300ft, you may feel that you could make it. If you are on the centre line, you need four turns. LLLR or RRRL. In each you will lose at least 75ft, with no engine. Smoothing all of these into a constant turn won't really help as you will trade speed for height and the final turn(s) will result in a stall/spin.

But why don't we climb out on a vector away from the centre line?

An engine failure on the hedge, at 300ft, 100m to the left or right of the centre line means two turns could, potentially, have us back in safely.

It seems that we are flying on the principle that the engine never stops and this teaching is killing us.

I am very interested in peoples views.

[Keygrip]

VERY interesting thought.

Having listened to so many "pre take off" briefs from pilots, I've been actively wondering for some time about the effect of a crosswind on departure, in the event of an engine failure after take off (because nobody brings it up).

Assume a crosswind from the right - turning back in a right turn would have a smaller turn radius than turning back with a left turn. A document I am reading just now suggests the turn radius of a "modern lightplane" will place the aircraft 2,240 feet to one side of the centreline at the end of a 180° turn at rate one. That's over a third of a mile - with still two alternate turns to go in a very low performance glider.

Now factor in airfields with parallel runways, winds from various "quarters", calm winds (oxymoron?) etc. and I would ask how do you train a zero hour student to mentally juggle the options for departure from each individual runway of each individual airfield.

I do like the question you pose, though. I, too, would be very interested to hear comments from others.

[Genghis the Engineer]

Come to Popham, flight straight on the centreline on either approach or departure on 08/26 not only is discouraged, it's likely to get you banned from the airfield.

All down to local procedures, but it is true that perhaps a few places should think harder about the appropriateness of their local procedures.

G

[Onan the Clumsy]

You're taught to fly the centreline for operations at airports with parallel runways, so you won't drift into the other departing traffic.

Having said that, I usually got "fly runway heading" probably because that's what the big jets do on departure.

As was pointed out local published procedures should win this argument.

As for a departure with an xwind, then sure turn into the wind - if you're going to turn. Alternatively, keep your eyes peeled for various places in front of you, in an ever widening triangle for a put down.

btw, one of the sailplane drills we practiced was a rope break at 500 ft, hand a 180 and bring it back to base :ok: Good training too as we had a guy do it for real on his solo :eek:

[IO540]

I read a very technical article recently calculating how a 180 turnback is possible if the runway is long enough and there is enough headwind, etc. In the limiting case, it also requires doing the 180 turn right on the stall limit; something that would require nerves of steel and very good training.

[Paul_Sengupta]

It would also depend on your plane's climb vs. glide performance.

As has been mentioned, it's taught technique in winch launched gliders. But then they do have a rather higher angle of climb than of descent.

[Flying_Anorak]

As a reasonably experienced glider pilot I must point out that a 180 degree turn in the event of a winch failure is NOT taught as standard practice.

A few years ago the BGA introduced the letter 'E' into the pre-flight checks of CBSIFTCBE to represent eventualities. One thing that is absolutely rammed home (and woe betide you if you forget it on a check flight) is that in the event of a launch failure you lower the nose and do not even think about turning until you have at least the days approach speed indicated. This is usually circa 55kts based on 50kts plus half the wind speed. Unfortunately there have been several fatal spinning incidents as a result of departures whilst attempting to turn at too low an airspeed after a launch failure.

As part of the 'Eventualities' check it is usual to plan to land ahead if it is possible to do so, if not, then to turn in such a way as to maximise the available area to land in, e.g. an 'S' turn or a 270. A 180 downwind is an option, but its not ideal.

Although cable breaks etc aren't that common these days the average pilot will have done loads before he goes solo and personally I always expect each launch to end in failure. That way I'm pleasantly suprised when I get to 1,500ft or thereabouts rather than being shocked when it doesnt!

[LD Max]

A very good question posed by Bar Shaker. I don't have any figures to hand, I'm afraid, but leaving the issue of parallel runways aside, each runway and departure has a protected area which is guaranteed to be clear of obstacles. This protected area provides a straight margin of safety, either side of the runway, and then expands in a cone from the departure threshold.

Assuming a runway of (say) 1,850 feet, and that a light aircraft or microlight - while using the full length, may rotate within the first 300 ft or so - at which point would you deviate from the centreline? Any immediate deviation, would surely take you outside the protected area into potential conflict with obstacles, such as the tower, masts, antennae or other buildings.

A deviation past the threshold would be less severe, providing it remained within that expanding cone, (which I can't remember the figures for). However, I doubt it is a significant enough angle to make a lot of difference as you describe.

However, the mantra of "no turns below 500 ft agl" it has to be said is going to be a "catch all" phrase which would work at any airfield. Indeed, on a long runway, 500 ft may well be achieved within the airfield boundary!

So as Genghis the Engineer pointed out, it's all down to local procedures and knowing the airfield.

I would point out, though, that there is no rule to say that you need to "make the runway" if you did elect on turning back. Landing across the runway, or on the grass, or on an alternative runway, or even on a taxiway, the ramp or the carpark, are all viable possibilities. The only logic to the decision to turn back is if there are no viable landing spaces available ahead. The other advantage is that the emergency services based on the field can get to you a lot quicker.

Other than that, I would encourage any pilot to know before takeoff what his / her options are. At Titusville, in Florida, one runway would drop you straight into the river between the field and the space centre. You really should know that before you take off and be prepared for a possible ditching.

[Hairyplane]

A useful debate which some have sought to confuse with irrelevant local procedures.

If I have just taken off in a 20kt crosswind - and if I have the height to make the turn - I am going to be looking for an into-wind field and take whatever component available that will reduce the speed I hit anything at.

If you discipline yourself to 'Never turn back' and also, 'avoid turns greater than 30 degrees either side of the centre line' - 2 factors rammed into me during my initial and Flying Instructor training - then you are much more likely to stay alive.

Airspeed, and plenty of it is the key to survival. You must fly the thing, first and foremost. If you load your brain up with other factors, the aircraft won't take care of the airspeed for you.

Turning back is a bold decision that is more likely to kill you - period. However, that decision has been made succesfully by others and who can criticise them if it works out?

I am sure they will agree that the margins were eroded and yet had good reason to do so.

On one occasion not too many years ago a rotary-engined type quit shortly after take-off yet the pilot succesfully landed back on.

It appears that he had already decided he was dead in the inevitable soft-ground rollover and decided to push the nose down, turn steeply ( more than 90 degrees of bank), aim the lift vector at the field, pull hard and - well - you need to watch the video.

He will be the first to say, 'if you haven't been trained to do it don't try it'. On this occasion he decided on the options, didn't like them and invoked his prior training as a military test pilot to get him out of trouble. Bravo or what?!

In display flying we have a good brief on the suitability - on the day - of surrounding fields for forced-landings.

We practise EFATO whenever possible.

As a hobby pilot though, I aint turning back.

An interesting engine failure story -

I was in Reno last year and got to talk about the Ryan PT22 and its very poor glide ( well - like a block of flats actually). He said, in a wonderful Southern drawl, 'If that Kinner stops poppin', shove the stick for'd and get a good look over the nose, coz thats where yer landing'.

We then discussed an engine failure at height. He said, 'reach for yer car keys, throw'm over the side and follow em down, coz thats where yer goin'.

I appreciate that a tragedy has prompted this debate, and some unfortunate hearsay or otherwise speculation.

I for one want to hear about the actual facts - for these can only serve to heighten our awareness (and maybe cause us to think that accidents don't only happen to other people) but will only rely on the AAIB report for education.

Only then are you qualified to think, ' I would have done this or that under those circumstances'.

Speculation is pointless.

HP

[foxmoth]

One reason to think a bit before drifting off the centerline is other aircraft, an aircraft going around should be on the dead side of the runway and looking for you on the centerline, if you drift onto the dead side and he does not have you in sight there could be a loud bang. Also, if you are staying in the circuit it can screw the circuit up by giving you a short crosswind - I am not saying going off centerline for the reasons given is neccessarily a bad thing, just that there are other considerations in doing so. :ok:

[BoeingMEL]

A healthy discussion but...
1: Pilots of light aircraft very rarely enjoy the luxury of parallel runways in the UK
2: To fly a vector (as opposed to maintaining runway heading) immediately after becoming airborne would require a steepish turn at low speed and low height. (Not great practice!)
3: The best vector for a potential 180 after EFATO would certainly be wind-critical.
4: Since, statistically, the engine failure may have been suffered by a student or low-time pilot, a single clear course of action embedded in the mind is the proven way.

Hmm..think I'd rather hit a barn at 65 knots rather than spinning in from 150'.... Good luck anyway guys.... my aviating days are finished forever..multiple sclerosis taking more out of me every day. bm

[BEagle]

We did some trials in a PA28 last summer - at a safe height, of course. The brief was to be climbing at 85 mph at 3000ft, the other FI would then close the throttle some time after 3300ft and the handling FI would then fly a descending steep turn through 180 deg, with the non-handling FI noting the height loss.

We concluded that a 'turnback' at anything more than 5-600ft above the simulated runway might be successful if the pilot immediately entered a steep descending turn at 45 deg AoB into wind. But it was a very demanding manoeuvre and we doubted whether the average pilot in average recency with average handling skills would be able to cope.

[buster172]

Hi,

I don’t have a great deal of experience but this subject has been on my mind as well so if I may,

Where I fly a motor glider we are taught, in certain conditions, wind speed less than 10 knots that if we have an EFATO between 300 and 500ft we have the option to turn back. The runway does have a parallel but that’s just a bonus. We can turn safely and get back onto the active from 300ft.

We have to demonstrate this and all the other bad things that can happen every 3 months so I am confident I can do this safely.

However at the other airfield I fly from with built up areas and power lines crossing a river the options are much worse. Having discussed this with my instructor recently I asked why we have to fly such big circuits well out of gliding range. I think it all came down to the requirements of ATC and having us fit in with the larger aircraft that operate at the airfield. This makes me a little uncomfortable but I have found is not uncommon.

All through my PPL training it was drummed in never turn back. Well, having been shown there are options, rather than one hard and fast rule I must admit that modifying the departure to ensure I crash on the airfield rather than in the river, houses, power lines etc is in my, inexperienced opinion a far better option.

As said before each airfield is different and I have only been to a handful but I would be interested to hear more on this subject. I have this nagging feeling my engine is going to fail all the time!

Interesting discussion,

Regards,

Buster

[jayemm]

I know it sounds daft, particularly in the context of this thread, but I had taken away from my training the 'generic' EFATO procedure, and had just "walked it through" at homebase during refreshers and practice.

I agree with Genghis. The more technical points discussed in this thread will not be in the average PPL's mind when all suddenly goes quiet up front.

I suspect that for many "hobby" pilots the practice that would increase survival chances is to check out the geography of the airfield you're visiting and plan what would happen if you had an EFATO in that specific location. e.g. checkout the local procedures.

Thinking about this further, I do not remember seeing many EFATO procedures displayed on local club/airfield notice boards.

[Gertrude the Wombat]

Pilots of light aircraft very rarely enjoy the luxury of parallel runways in the UK Taking off on 23 main from Cambridge you've got anyone taking off from 23 grass to your left (operating both runways at once is allowed) and anyone going around deadside to your right. Not surprisingly instructors are not very pleased with people who don't climb out on the centre line.

[bar shaker]

GtW

I would think the instructors are even less pleased with people who turn back, crash and close the runway for the rest of the day. Especially when there is a perfectly good housing estate for them to crash into, just over the fence.

I came up with the idea of moving off centre line last year. My farmer normally leaves bits of field as EFATO strips for us, but hadn't on this occasion. Freshly ploughed fields, together with a couple of days of recent rain, coincided with a terrible case of carb ice on climb out. I decided to turn back and use the field along side my runway (it being fallow grass) for a downwind landing. In the end, the ice cleared and I didn't land, but I was lined up parallel to my runway.

But the whole episode made me think. Had I been 100m to the left or right, the runway would have been accessible with a minimal amount of turning and its consequetial height loss.

To have this option at many/most established airfields would take a sea change in thinking and in procedures. But something needs to be done as our approaches get more and more congested with houses and industrial units. EFATO has killed several people in the past year and these occurances should be survivable every time.

If you are on the centre line, your chances of making a turn back, in any light aircraft, are vitually nil. If you are off centre line, those chances increase dramatically.

[Gertrude the Wombat]

Especially when there is a perfectly good housing estate for them to crash into, just over the fence. Well yes, there is that, there isn't an awful lot of choice straight ahead on 23 (which the people living there know perfectly well and keep complaining to their councillors about). You can backtrack and use the whole runway so that you're crossing the airfield boundary at 600' rather than 500', but there will still be several seconds during which an EFATO is going to be really bad news.

[OneMileHigh]

The first thing to bear in mind in an EFATO is survivability, not saving the aircraft. That has to be sacrificed if necessary. So leading on from that, most airfields will have somewhere ahead to achieve the survivable crash!!! If there really isn't anywhere ahead, as seems to be the case at Sywell, then perhaps a special procedure should be devised.

On the safety issue though, the turn back should never be considered below 500ft.

But why!! I here some cry!

An experience I had will illustrate why. I have a few hundred hours gliding experience from the distant past, and one incident in particular I remember well. I had a winch launch failure at 400ft, but as the launch speed was slow all the way up, there was insufficient airfield ahead to land in. I had foolishly hung on to the cable hoping that the damned winch driver would open the throttle more. The though that the winch may not have been developing enough power hadn't crossed my mind. It was a thermic day and I wanted UP!!!

I elected to turn and land back on the airfield downwind rather than ahead into a field.....Pride was at stake. So, decision made I made the turn, and what followed frightened me:

At low altitude you will get a distinct impression of speed from seeing the ground so close. With the initial headwind it all seemed so easy, but then came the fear! As you turn through 90 degrees and across the wind the ground seems to be moving very fast, and there is a tendency to pitch the nose up thinking the speed is too high......Fatal. I knew I was slow in the turn but fortunately I had enough experience to resist the visual cues and fly by feel, and I pitched the nose down again.

So, I accept I was foolish to turn back (even in a glider), but I managed to land back and by using the available width of the grass airfield minimised the effect of the tailwind by landing more across the wind. BUT, I was pushing it wasn't I? I estimate that as I turned through the crosswind I was very close to the stalling speed, and we all know what happens then!!

I believe now that apart from the height loss in a turn, one of the main dangers is the visual effects close to the ground and the consequent urge to pitch up because of the impression that the speed is too high.

I really learned from that experience, and I'm definitely in the EFATO land ahead camp, unless there is really no alternative (Sywell perhaps) or there is plenty of height to play with.

[shortstripper]

OMH,

I think you are quite correct about turning back below 500' in light aircraft. We used to work on 400' as ok in gliders, but wind strength, direction ect all adds to the equation. Talking gliders .... a "soggy" winch launch is probably one of the most likely ways to get caught out; far more so than a usual cable break. I used to love scratching for lift down at 500' (but only after a suitable landing site was identified) and you soon get used to flying by feel.

The famous "downwind turn" is very real in the circumstances you describe; especially if you are a) Not used to low level flight, and b) unused to flying your aircraft without the fan! ... It is surprising how fast the ground comes up in a poor glider in a turn!

SS

[LD Max]

Has anyone got an MPEG of an EFATO with turnback? Probably as rare as rocking horse doo doos I know, but I know the CAA use one in their safety videos.

(I did ask, but was told it was from a German Gliding Website).

I'm helping a buddy put together a PowerPoint presentation on EFATO and something like this would be useful.

In fact, I think I'll post this as a new thread

[andrewc]

All the more reason to be climbing at max rate after takeoff to minimise your occupancy of the 'nowhere to go' zone if the donkey gives up...

-- Andrew