Vmid a new call-out speed on TO and Landings

[aardvark2zz]

Vmid a new call-out speed on TO and Landings

With the following:

- 747 TO crash in Halifax last year.

- Blue Grass Airport wrong runway TO.

- Runway overruns on landing.

- Other numerous accidents.

- Not much training in rejected TO for PPL and other ratings.

With V1, Vr, V2, etc.... I believe they should have mid-runway signs for which there should be a Vmid (mid field) call-out by the pilots so that when the pilot sees the mid-field sign and notices that his plane's speed is below Vmid then he can call it out and reject the TO.

Would probably have saved the Halifax 747, Blue Grass crash, and other accidents.

Put some signs on the side of the runway at mid-field and/or paint some very visible clearly labeled lines on the middle of the runway.

I believe there are some runways that have markers/signs every 1000 feet but these are not systematically used fully in TO and landing procedures.

Could also be very useful on landings to determine braking effectiveness and amount of pressure to apply to brake pedals.

It would be a great idea.

I wonder what past proposals and research work has been done on this.

Here is a crude example of what I mean with the large special marking in the middle (half white half black with a clear perimeter wrt runway color):



For the Kentucky accident the wrong runway mid-field speed was, I calculated, approximately 97 knots and therefore a Vmid here would have been (let's say) 120 knots.

At the mid-field mark the PNF would have said "Vmid 97 knots" and would have realized that the 120 knot target was not attained and would have called out for a rejected TO.

Similarly for a landing. If a plane's speed at the mid-field was above a target speed the pilot can immediately apply max braking pressure or, if he can, do a Go Around.

[Ka8 Flyer]

So, assuming you don't reach Vmid by the signs, how do you know that aborting is the safest option? Maybe a continued takeoff and normal rotation without any further problems occuring would have saved you from running into the field?

[jondc9]

this concept has been explored and discussed before...there is some validity in it.

but the $ or the POUND STERLING or whatever seems to bother us all.

runway remaining signage is a darn good idea, on the side of the runway or painted on the runway with a big picture of GW Bush( that would scare the hell out of anyone))

some airports have signs, military airfields do.

there is something I tell my flight attendent friends who aren't in a position to see the takeoff...the estimated time to rotation is about 30 seconds in most jets...longer at high hot airports or with full pax and fuel, shorter at cold low airports with light pax loads. perhaps a simple timer beeping at 17 seconds or so might help the pilot, perhaps it would be a distraction.

perhaps for too long we judge acceleration by the seat of our pants?


80 knots is a callout now at some airlines...are things going well at 80?...keep going...something not right...NOW is the time to get it squared away or abort.

we also use something called MIN V1, but that is a whole other ball of wax...it allows a better abort option and encourages a GO.

a good idea worth expanding on...but $ and idiots in the FAA and others such places along with backward thinking management will doom this idea(though I hope not)

j

[Panama Jack]

How about getting some of these guys out on the runway?

[Mad (Flt) Scientist]

Sounds like you'd need a chart for "speed at distance X" where X is variable dependent upon which runway is being used, and all the usual parameters affecting takeoff distance calcs would also apply. So it wouldn't be a simple chart.

Then you have to decide whether the chart should have any implicit conservatism or not? Should we post a speed at distance X corresponding to 'minimum' performance (i.e. consistent with the existing AFM data) or consistent with nominal performance? Either has pros and cons. It may not be possible to 'collapse' the AFM data as neatly as for the existing charts, especially if you're not trying to present minimum data.

[ZQA297/30]

In this day and age with huge computer capacity, wouldnt it be easier just to compare IAS and GS against runway used (wheel rotation counter, or GPS) and have a simple Go/NoGo display on the panel?

[Mad (Flt) Scientist]

No device capable of commanding a high speed RTO will ever be either "simple" or "easy". You're looking at a level A software implementation and significant certification effort.

Its not that it can't be done, but it's not trivial to implement a hardware/system 'solution'.

[click]

Dream on.... Captain's call to reject or continue and giving another speed to call out is like giving the lawyers another noose to hang us on. I highly doubt it would have saved the Kentucky crew....doing a high speed reject is a dicey thing at best. You've got numerous variables to account for and keep in mind that they thought that they were on the proper runway..... my first reaction given your scenario is to look for a problem in the aircraft....after all, I am on the proper runway right???

[Alpine Flyer]

I remember reading about an "acceleration monitor" that would show a green band of "OK accel" around the airspeed "needle" that would increase according to distance travelled or whatever. Below the green band an amber band would show low acceleration and an (even octagonal) stop sign at the lowest end of the indicator would show insufficient acceleration.

To really reflect all parameters that go into MTOM calculation such an indicator probably needs quite some computing power but it should be feasible.

[barit1]

There has been the idea of a acceleration check on this (& other) forum for a long long time. My drinking buddy and ex-B-52 driver reminded me of their timing check - a time limit from 60 to 120 kts or thereabouts - but it won't help if you're on the wrong runway.

I'd be the last guy to call for another dashboard delight, but a short-range transponder (aircraft => end of runway => aircraft) could provide distance, velocity, and acceleration data that could essentially eliminate r/w overruns if intelligently used.

However, like any new law in the mill in Congress, it should only pass if 3 or 4 old laws can be consolidated, simplified, or abolished.

[Loose rivets]

I was hoping to make my fortune in the 70's with such a device. below is one of the threads.



http://www.pprune.org/forums/showthr...er#post2151778

[BEagle]

I'm not convinced that the folk who:

- Use incorrect TOW;
- Ignore the effect of tailwind on RTOW (AF Concorde accident...);
- Use incorrect contaminated RW procedures on take-off or landing;
- Touchdown long and hot on very wet RWs;
- Don't understand 'slippery when wet';
- Don't check they're on the right RW:

would be saved by any other gizmos than already exist.

[skiesfull]

I'm with BEagle on this one. It was instilled in me at a very early stage in my career, to check various vital facts in addition to whatever the checklist included. Since then, all sorts of gadgets, gizmos and devices have been added to make the pilot's life easier and safer, with limited success.
My own mnemonics for take-off and landing are as follows:-
T/O... CRAFTS Correct Runway, Autobrake(rto),Flaps,Thrust,Speeds
LDG... SAGFA Speedbrake(armed),Altitude(G/A alt. set), Gear down,Flaps(land setting),Autobrakes(as req'd).
I welcome any device to prevent the repetitiveness of T/O safety incidents and LDG incidents, but the onus really is on the Captain to ensure that the flight is concluded safely. Using the above mnemonics works for me - there has to be an airmanship back-up to all automatic advancements. Total reliance on automatics and checklists is not the answer.

[jondc9]

skiesfull

regarding your view on automatics and checklists, I agree.

good people, well trained, properly motivated to do an above average job without having to worry about paying the rent or ill loved ones is the way to make flying safer.

I would welcome sim tim every 90 days instead of the new concept of once a year.

More schooling on the finer points of aviation, including disecting accidents and incidents in the past.

learning how to recognize going down the same path as flight XXX which lead to disaster.


j

[Two's in]

All the drives towards even more automation, checklists, and safeguards would be understandable if we were picking Joe Public up off the street and putting him into an ariline cockpit, but we're not. In almost all countries, the ATPL requirements require (quite rightly) some of the most demanding criteria for training and subsequent employment there are. The medical and requalification standards ensure that the high level of professionalism attained are adhered to. That always seems to be overlooked following an accident or incident, the fact that in general, these are well above average individuals who are trained to a very high level.

As jondc9 suggests, instead of making everything so Micky Mouse that this degree of training is not required, why not instead leverage that above average ability to better understand the failures attributable to the human condition, and recognize risk scenario's before all the unrelated events align and cause an accident. CRM was widely scorned when it was first introduced, with a lot of unprofessional attitudes towards joint problem solving and work share in the cockpit, but eventually it was recognized as a valuable tool for flight safety. Is it not now time to apply the same initiatives towards risk management and accident avoidance training?

[aardvark2zz]

Since FMS computers are becoming more and more common, I guess the solution will be to have the computer detect the actual runway used, location, distances to both runway ends, TO direction, from GPS and the compass and independent of what the pilots enter !!!



Too bad the bureaucrats will take 20 years to improve things !!



But that still leaves the older cockpits.



Until then I say paint the god-damn midfield lines or put signs midfield.

[DC-8]

Originally Posted by Alpine Flyer

I remember reading about an "acceleration monitor" that would show a green band of "OK accel" around the airspeed "needle" that would increase according to distance travelled or whatever.

Actually this philosophy was used in the old Caravelle. Depending on your weight, temperature, elevation... with the performance charts you got a maximum amount of time to reach a given speed. If at that time you was above that speed, then ok. But if below... you had to reject the take off.

From my point of view this procedure was safer than V1. Because if you reject a T/O below V1 but acceleration during the T/O roll was poor you can be very close to the end of the RWY despite of being below V1 and therefore have a RWY overrun.

[electricjetjock]

It will not work

AArdvark2zz

Unfortunately your idea would not cater for the many and variable factors affecting takeoff performance and landing performance.

How would your fixed markers cater for each type of aircraft, weight, runway, contaminant, windshear etc etc etc. Your fixed point is meaning less - V1 is not fixed!! Yes in the military we had 1000' markers but we certainly did not calculate our take off and landing distance, on fast jets, in the way Performance A is calculated on commercial aircraft. Speeds dependant upon weight and TLAR as we went down the runway. If it was all going pearshaped then the markers would give me an idea of when I had the last option of a Martin Baker letdown!

Fine - the boffins come up with a computer programme to cover this scenario, so much information would have to be input that there would be more errors entering the information and thus negating the whole point of the exercise.

Vigilance and adherance to procedures and checklists is the only way we have of trying to break the chain. People call it all sorts of new buzz words these days CRM TEM etc but it all boils down to AIRMANSHIP. We are paid to carry out thus job and we should do it in an extremely professional way. We should treat every takeoff as a possible emergency and be ALERT to anything out of the ordinary as a CREW. Complete the required paperwork before taxy or leave it until you are airborne and concentrate on the job in hand - taxying, listening out and taking off on the correct runway.

[Intruder]

First, the VMid concept will not work when V1 is achieved prior to that marker. That includes all cases where the runway is relatively long and the takeoff roll is relatively short. It also includes MANY cases where V1 and VMid are close to one another. Further, developing the data and procedures to use the concept will take a lot of time and money.

Even using an already-known and -proven method of checking acceleration will take a lot of time and money, if it has not been universally adapted for airline operations. As an example I'll use the "Line Speed Check" used in many military operations:

In my previous life I also used a "Line Speed check" as part of takeoff performance calculations in fighter jets. While it is a concept easily adaptable to the transport world in theory, there would have to be a LOT of infrastructure and data improvement to incorporate it in reality.
In essence, the check is for a minimum airspeed after a certain length of roll. Inputs (to a chart/table/graph or a computer) include the already-used airplane gross weight and weather conditions, plus EITHER a target airspeed OR a length of roll. Output will be the missing parameter (length of roll or minimum airspeed).
Since an 80 KIAS check is common in many airlines, and that is well below V1 for most (all?) airliners, that is reasonable for illustration purposes. If 80 KIAS is input to the Line Speed calculation, the table or computer will give a distance, say 1000'. The Pilots now know that 80 KIAS must be reached before 1000' of roll, or the takeoff should be rejected for performance.
HOWEVER, that 1000' needs to be translated into a visible checkpoint. The options commonly available are Runway Distance Remaining markers to the side of the runway and the Fixed Distance Markers painted at the approach end of IFR runways, straddling the centerline. The Pilots would have to know which of these references is available to make their crossheck. If the Distance Remaining markers are used, the known runway length would have to be known, and the data translated -- manually or automatically -- to a reference marker (e.g., "80 knots by the 9 board" on a 10,000' runway). Also, procedures and training would have to be developed to explicitly add those items to the Pilots' scan on takeoff.
Since not all runways have one or both of these distance aids, the infrastructure enhancements would include adding them to every runway at every airport used by any airline. The performance data for each airplane would have to be supplemented to allow the Line Speed calculation, and I suspect this is NOT a trivial or low-cost matter.
Finally, this added check may not have had any effect whatsoever on the flight in question. Were there Distance Remaining signboards on EITHER of the runways? Are the Fixed Distance Markers on the runway easily visible at night or in the rain with the lights available on the airplane? Would procedures include a mandatory "Reject" if the appropriate FDM is not seen (e.g., when they do not exist, as on a VFR-only runway)?
What seems like a simple "fix" turns out to be much more complex and costly than the OP may think. Is it worth the added cost and complexity for an unknown added value?

[FullWings]

The idea of some sort of 'takeoff performance monitoring' device has been discussed and experimented with for decades but we still don't seem to have such a thing in commercial aviation. (There are products like EFB but they only provide a partial solution.) I have reached the stage where I believe that there are no significant technical obstacles to the introduction of a monitor like this and every year it is delayed, we lose more aircraft. I can only deduce that it is something to do with the perceived cost but preventing a hull loss would pay for a lot of TPMs...

As I see it, there are a handful of nasty 'gotchas' when trying to leave the ground:

Using the wrong runway.
Using the wrong part of the right runway.
Using a parallel taxiway instead of the runway.
Using a power/flap setting inappropriate for the takeoff distance available and/or the aeroplane mass.

These are not the only ones - I'm sure there are others but these seem to be the mistakes which usually cause a serious accident.

Compared with the scenarios that other warning systems protect us against, detecting the first three items is fairly trivial; the last would need some work but again, there is not an extreme level of complexity here. The software required to make EGPWS and TCAS operate in the manner that they do took, I suggest, much more R&D to produce than that needed to solve the problems listed above. After all, we are comparing one- or two-dimensional problems to some in three and more.

A GPS driven FMC from the last decade or so already has most of the information required by a TPM: runway endpoints, track, groundspeed, mass, position, etc. In a simple implementation you could program it to set off the config. warning when triggered; a look-ahead system could warn you before you even attempt something dangerous.

I am disappointed that the regulatory bodies have not mandated the installation and use of such systems, much in the way they did with TCAS. I wonder how many more accidents/incidents it needs?