OVERRUN! Safety issue.

[de facto]

American Airlines Overrun Prompts Safety Recommendations

AINSAFETY » JULY 9, 2012
by ROBERT P. MARK

July 9, 2012, 2:51 PM
The NTSB sent the FAA three new safety recommendations in the wake of the Dec. 29, 2010 American Airlines incident at Jackson Hole Airport (JAC), Wyo. when a Boeing 757 ran off the end of the runway while landing. Recommendation A-12-44 requires operators of speedbrake-equipped aircraft to develop training that recognizes when speedbrakes do not automatically deploy on landing. A-12-45 will require new Part 25 aircraft to include a system that easily alerts pilots when speedbrakes do not deploy..

Overrun happen on a regular basis,what is your take on reducing such threat?

Putting more emphasis on manual skills(landing at the right place)?

Strictly implementing SOP to stress the need to clearly call out the failure of AUTOMATIC brake or and speedbrake deployement.?

Forcing pilots to calculate their landing distance (SOP) before top of descent and come up with contingency plan if landing distance becomes marginal.?

Practice balk landings and touch and go more often in the simulator.?

Identify risk taking individuals via FOQA(high speed taxi,recurrent unstable approaches,long landings..).

Do you think reasonable to get yet another oral warning if the speed brakes do not deploy?Is it intended to cover a possible lack of adherence to SOPs,poor crew training?

[FlightPathOBN]

make FOQA data public....keep track in a database...

[Intruder]

The more warnings we get, the more we will either ignore or overreact to them.

We already have training programs in place. What we need is an environment where we are not threatened or embarrassed by a go-around or balked landing or diversion. Until our employers GUARANTEE we will not be questioned or punished for such decisions, no amount of regulation will help.

[westhawk]

The specific actions to take regarding ground spoilers/airbrakes/lift dump will vary according to aircraft type. In many types it's already SOP for the PNF to verify ground spoiler deployment after touchdown. I'm not confident that installing yet another monitoring device is the best answer. Would the device tell you what to do about it?

What do you do when the device alarms anyway? When should it activate, some particular time after touchdown or wheel spinup? At what point during the landing should you consider yourself committed to the ground and when it is better to spool up and lift back off? Will a warning trigger a particular set of actions? Does the absence of a warning mean everything's okay?

Too many questions to be answered on too many airplane types to consider this a realistic replacement for the flight crew doing the job as already defined and will certainly not replace the exercising of good judgment. Judgment is the one factor which seems to come up in most overrun incidents and so is probably a better target to aim at in reducing overruns.

In the Lear 60 it's SOP to arm the gnd spoilers before approach (appc checklist) and verify deployment after touchdown. In some of the older 60s without wheel spinup activated spoilers it is wise to manually select gnd spoilers since these acft may not get an auto-deploy if the squat sw doesn't activate. In the Westwind and Hawker, lift dump is manually selected since no auto-deploy exists for these types. In these aircraft, it is the 2nd pilot's duty to verify deployment just like when the gear or flaps position is changed.

At all times and especially on runways where stopping performance is more critical, proper discipline and planning are the most controllable factors which might have prevented the most overruns. Perhaps that is where efforts would be more appropriately focused. I wonder if anyone has done a statistical analysis of overrun causal factors and if so is there any correlation to the level of automation relied upon to stop the airplane safely. It just seems possible to me that sitting there waiting for things to happen automatically may potentially leave the door open to mishap more than being required to habitually take a series of manual actions following touchdown. Several overruns in the past come to mind where this was a factor.

So does anyone else think that automation dependency might be a factor in overruns and that adding more might not be the best answer?

[Centaurus]

So does anyone else think that automation dependency might be a factor in overruns and that adding more might not be the best answer?


Pilots on a visual approach leaving the autothrottle engaged (depending on aircraft type of course) while manually flying on short final, you know that automation dependency has them by the balls.

[de facto]

So does anyone else think that automation dependency might be a factor in overruns and that adding more might not be the best answer?

I certaily believe it is linked to automation dependency.
I have seen countless pilots forget to manual deploy the speedbrakes during a reject as their previous airlines had the auto spoilers linked to the refused take off switch...

For the landing part,I believe a briefing emphasising the importance of PNf monitoring the auto brake and speedbrake after touch down would be a good start?

[TheRobe]

Comes down to a pilot making a decision to land at that speed, touchdown at that spot, at that airport.

[safetypee]

Like most aspects in flight safety no single intervention will assure it, thus a range of solutions is required.

There is a good overview in European Action Plan for the Prevention of Runway Excursions (www.skybrary.aero/bookshelf/books/2053.pdf); however, this places significant responsibility on the operator and lacks detail to aid a consistent approach. Operational aspects are described in App E and the manufactures’ and regulators’ in F - H.

“… automation dependency might be a factor in overruns …”
Use of autobrake removes opportunity for pilots to gain a feel for the brake effectiveness for the amount of brake applied (pedal force / angle); this is further complicated with use of thrust reverse which might provide the majority of the demanded deceleration. Lacking of this type of experience may result in deducing a brake failure when reverse is cancelled, or not appreciating how close to a safety boundary an operation is.

There is potential for pilots to rely on automated distance calculations, thus overlooking the very necessary judgement on the variable accuracy of significant factors such as braking action and wind information.
Similarly, new alerting devices for long landings or reducing distance available after touchdown may provide a false sense of security. Generally these are retrospective; the warning may be too late to take meaningful action.

[decurion]

I have studied landing overruns for a long time now. I also worked on the European Action Plan for the Prevention of Runway Excursions (http://www.skybrary.aero/bookshelf/books/2053.pdf). Like many other occurrences, overruns are caused by more than just one factor. An important issue I found was that pilots often do not know what the basic assumptions are that have been made by the manufacturer for a landing. The (inflight) landing performance data that a pilot has for its aircraft arebased on a number of assumptions which involves the pilot. First of all it is assumed that you land with a certain speed and touch the runway at a certain distance from the threshold. Many manufacturers use a fixed distance for this airborne distance (this is going to change in the near future following the TALPA ARC).Then it is assumed that you lower the nose without any delay. Next if you had decided that you wanted to use reverse thrust it is again assumed in the performance data that you select this a certain time after touchdown. The same is true formanual braking. Finally it is assumed that the ground spoilers are deployed (if you have these installed of course). Any deviation from these assumptions will eat away any margin you had on the available runway. Indeed most landing overruns are related tolarge deviations from the performance assumptions: long landings and late use of stopping devices. For instance delaying the thrust reverser selection could result that you go into ground idle. When selecting reverse thrust in this modeit would take twice as much time to get maximum reverse than when you are inflight idle. On a slippery runway this could mean that you go off the end ofthe runway. Information about the assumptions made in landing performance data is not always easy to find. The FCOM and FCTM often have little quantified information (typically it will state things like “prompt”, “without delay”,etc.). I believe that we can help reducing the overrun threat by informingpilots about the assumptions made in landing performance data and by giving pilots more understanding of what the consequences are of deviating from these assumptions. Of course when you deviate from an assumed action it will not automatically mean that you will always overrun the runway.

[PJ2]

FlightPlanOBN;

Re, "make FOQA data public....keep track in a database... "

Back in the 90's the distributed archive project in the U.S. was intended to do such a thing. Not sure what happened to it. It was de-identified as to airline etc and focussed on aircraft type, for obvious reasons.

That said, such data shouldn't be "public" in the sense that anyone can take a look at it.

Back OT, one of our FDM Program events provides data on over-run potential. As such it is a useful tool in the overrun prevention kit.

The event determines the runway remaining from the touchdown point using ground speed and a standard, nominal deceleration rate. If the runway remaining is a negative number an event is created. There's more to it than this of course but that's the FDM principle.

PJ2

[zerozero]

Sure there are lots of reasons for rwy overruns but for the most part they all result from unstable approaches and long landings.

I'd be willing to bet that most crews KNOW--as they continue their unstable approach and long landing--that it's a poor decision. And yet, continue they do.

Therefore my conclusion is, there is a BIG reluctance to abandon a poorly managed approach. In other words, this is a psychological question.

Why are crews so reluctant to go around and try again? Answer that question are there is your solution.

[decurion]

"for the most part they all result from unstable approaches and long landings".

You are correct regarding long landings. In about 40% of all landing overruns this was a direct causal factor. Unstablised approaches are alsoan important factor but they are not the biggest issue as suggested by zerozero. An unstablised approach was a factor in less than 24% of all landing overruns.

Landing overruns are normally not caused by one single factor and some factors could be related (e.g. a high approach speed could result in a long landing, see Landing long: Why does it happen? (http://www.nlr-atsi.nl/downloads/landing-long-why-does-it-happen.pdf)).

[safetypee]

“Landing overruns are normally not caused by one single factor and some factors could be related”

In addition to the report on long landings (#12), the importance of combined factors is also indicated in a recent analysis of Boeing aircraft overruns ( http://flightsafety.org/files/ASW_nov12_sm.pdf). The chart on page 10 has three groupings; each respectively showing long landings associated with higher speeds, fast touchdowns with tailwinds, and use of deceleration devices and timing. A common theme in all data is the reduced braking action, but an important aspect relating what conditions were reported or perceived, vs what the actual braking action was, is not available.