What’s New in Runway Safety Human Factors?

Kim Cardosi

cardosi@volpe.dot.gov

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Today’s topics

The good, the bad, and the ugly of human information processing• Knowing how we process information helps

us guard against human errors.

Typical errors that result in runway incursions

What we can do to prevent and catch human errors.

Current Events

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Foundational Truths

Even the most professional, well-trained, well-rested and conscientious pilots and controllers can, and will, make mistakes.

With every error, there are multiple opportunities to catch and correct the mistake before they result in an accident.

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Controlled vs. Automatic Processing

“Controlled” information processing (fully attentive):• Slow, effortful (think learning to read or drive)• Required when learning new tasks or performing difficult

“Automatic” information processing:• With experience and repetition, even complex tasks become

automatic (reading, driving)• Fast, high-capacity, requires minimal conscious supervision

Allows your brain to go on auto-pilot as you drive home• Drawback: “Force of habit” is a double-edge sword

Automatic processing Is only error-free if all of the conditions of the successful past performance are the same – otherwise, the lack of attention will lead to error

• Can lead to errors that we attribute to “memory failures” (“I forgot”.)

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Double-Edge Swords of Information Processing

Automatic Processing• After much practice, responses are quick and effortless.

Expectations • Help you plan.• Expected responses are faster and lower workload.

BUT - Expectations only help when expectations match reality – a mismatch is a set up for error.

Automatic processing = errors due to “force of habit” when the situation appears the same, but is different.

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Confirmation Bias

Refers to the tendency to selectively attend to information that confirms our expectation.

Information that contradicts our belief is either not noticed or is discounted as either not correct or not important.

Common Errors in Runway Incursions

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Common Controller Errors in Runway Incursions

• Coordination errors between controllers(usually involving runway crossings)

• Controller “forgot” (about an aircraft on approach, aircraft holding in position, coordination that they issued) Forgot to issue a clearance (e.g., takeoff) they intended to issueProspective memory – most fragile (due to

interruptions/false memory)

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Pilot errors in runway incursions

Most common pilot error – reading back the instruction correctly and then doing something else

- Usually involves a correct readback of the hold short instructions

Most common factor cited (in ASRS reports) is one pilot being “heads down” programming FMC or conducting checklists.

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Analysis of ASRS Reports

Over 90% of the pilot who erroneously entered the runway for takeoff involved a communication error – they thought they were cleared onto the runway.• Compared to 32% of pilots who cross the hold short

lines but do not cross the runway edge.

Pilots are most likely to accept another aircraft’s clearance when:

-it is a clearance they are expecting

- similar call signs

Similar Call Signs

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Similar Call Signs

FAA – Flight numbers should be stated in grouped form (e.g., “five forty six”) 7110.65, 2-4-20

….Call signs may be pronounced using single digits if necessary for clarity

ICAO Standard – Numbers in call signs shall be transmitted by pronouncing each digit separately (e.g., “five four six”) Annex 10 Volume 2, Chapter 5, Section 5.2.1.4.1

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Similar Call Signs

Does format matter?

0 – 9 much smaller vocabulary set than 0 - 99

- important for non-native English speakers

Grouped form increases similarity between numbers • E.g., in grouped form, all of the numbers

between 13 and 19 rhyme, ‘fourteen and forty’ are more similar than ‘one four and four one’.

What’s New on the International Front?

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Conditional Clearances

Renewed efforts to eliminate/restrict use of conditional clearances.

Not used in the US, conditional clearances are ones that are only to be acted upon once the condition is met – e.g., ‘line up and wait after landing aircraft’• May not hear the condition - tendency to lock onto the

action word• Right interpretation – wrong reference

Also a concern with data linked clearances (oceanic)

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“Line up and Wait”

Movement toward “line up and wait”As of April 10, 2008 - the US is the only country that

uses “position and hold” instead of “line up and wait”. Canada changed from “taxi to position” or “taxi to position and wait”

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International Operations

Phrases US pilots thought they heard, and often readback, and as “position and hold”:• “cleared into position and hold”• “cleared into position”• “taxi to position”• “position and hold”• “taxi into position and hold”

But controllers outside the US have no way of knowing that “position and hold” does NOT mean “hold your position”

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Potential Confusions in the US

Potential Confusions with “position and hold”• “Hold your position” (“fail-safe”) but consider

the potential confusion of the pilot reporting “We’re holding in position” vs. “We’re holding our position”

Similar sounding/Opposite meaning

• “Use caution – position of the hold lines”

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Equivalent Instructions in Use

U.S Position and hold

Hold your position

Taxi to Runway X

Hold short

ICAO Line up and wait

Hold your position

Taxi to holding point Runway X

Hold short

Equates to clearance onto the Runway?

YES NO NO NO

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Change is Coming

Planned change from “position and hold” to “line up and wait”

No-Cost Way to Reduce Risk in Air Carrier Operations

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What the Data Showed

Most Serious (A and B category) Runway Incursions 2000 – 2002     • 47% involved crossings and potential crossings in

front of a takeoff (66% of the total A- and B-level incursions that involved non-GA aircraft).

• 15% involved a landover or potential landover • 11% involved crossings and potential crossings in

front of a landing aircraft (9% of most serious incursions that involved non-GA aircraft).

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Use of Landing Light for Takeoff (Pre-AC120-74A in 2003)

•Some pilots put all lights on when they taxi into position and hold on the runway (at night) and/or don’t use the landing light at all during the day.

•Other pilots consistently turn all lights except for the landing light when they take the runway and use the onset of the landing light as a signal that they are taking off or crossing the runway.

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Additional Considerations

Landing light does little to increase conspicuity of aircraft holding on the runway

- strobe is much more noticeable

Aircraft movement is very difficult/impossible to detect from a 90 degree angle at a distance.

Landing light is easy to see (from a 90 degree angle at a distance).

Landing light onset is an attention getter.

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“We flew a visual approach to Runway 25L…as we were exiting at intersection A6, tower cleared us to cross Runway 25R at intersection A6, I (F/O) cleared the runway. I did see an aircraft in the distance in what appeared to be in takeoff position, but saw no movement of the aircraft. At about half-way across the runway, I noticed the nose rotate and I told the captain to hurry across. The takeoff aircraft crossed behind us and about 200-300 feet in the air…..The motion of an aircraft nose on is hard to pick up at these distances. ATC tower controllers frequently taxi aircraft across runways with other aircraft holding in position.” (ASRS report number 466269)

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No-Cost Risk Reduction Strategy

Reserving the use of the landing light as an indication that the aircraft has received takeoff clearance and is rolling (or is crossing the runway) is a flightdeck procedure that can:•Help mitigate the effects of pilot error.•Help mitigate the effects of controller error.• Serve as cue to controllers, other pilots and

vehicle drivers that aircraft is taking off..

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Examples of Post AC120-74A “Saves”

6/27/07 OE Nashville Intl, TN (BNA) Ground Control (GC) cleared OPS14, airport vehicle, onto Runway 20C to clear debris. A short time later Local Control (LC) cleared AC#1, Mitsubishi MU2, for departure Runway 20C via the S-5 intersection. OPS14 saw the aircraft lights and exited onto the grass. (Aircraft continued departure.)

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More recently

January 2010 PHLB767/H/B767 landed runway 9R and was instructed to hold short runway 9Lvia taxiway T.  LCE issued a take-off clearance to DH8 runway 9L.LCW coordinated with LCE to cross runway 9L after DH8 departed. then coordinates via landline to LW to cross the B767 behind the departing DH8A. LW did not hear "behind PDT" and clears the B767 to cross., crosses the hold short lines but sees the DH8 illuminate and stops 15 feet past the hold line.  DH8 continues his departure and rotates past taxiway T normally.  ASDE did not alarm. Closest proximity was 110 feet the approximate distance between the nose of B767 and the wingtip of DH8 as the pilot passed the taxiway.

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Improvement needed

Compliance not 100% within US carriers

Recent crossing in front of a takeoff:Comments from the Captain - saw the Alaska aircraft on the T/O end of the runway. Alaska had all its lights on.  The Horizon Captain commented that it seemed that most the Alaska flights he saw were using all their lights when taking the runway.  He couldn't tell if Alaska was stopped or rolling, but because he was cleared to cross the runway, he assumed they were holding in position.

No international consensus.

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Beware of DIG

Doing more than one critical task at a time (you think you’re switching attention between multiple concurrent tasks, but you’re not as good as you think)• e.g., Re-programming the FMC during taxi

Interruptions to important tasks• Distractions• Prospective memory” – remembering to take a future action – is the most

fragile part of memory- Importance of task doesn’t help you remember it.

- That’s why we have checklists

Gaps in the safety net• Aka “shortcuts” e.g., “roger”s instead of readbacks• Inconsistent use of landing light as signal for takeoff

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DOPilots• Directly question the controller about an unclear instruction (NOT

readback what you thought you heard assuming the controller will correct any discrepancies).

• Directly correct any call sign discrepancies.• Use landing light as a signal that you are taking off.

Controllers• Set a tone on the frequency that doesn’t discourage questions and

challenges.

All Humans• IF something doesn’t feel right, take a mental step back.• Do the right thing every time – consistent use of best practices is the best

safety net for preventing, detecting, and correcting the errors that you and others will make.