On Situational Awareness

I was working the early morning shift at the Air Ambulance Shopwhen I happened to read one of the many articles written aboutcollisions between aircraft on what controllers call movementareas but what pilots know as runways and taxiways.

One of those articles mentioned the well-publicized collisionbetween a USAir 737 and Skywest Metroliner in position for takeoffat Los Angeles International one winter night in 1991. From theaccident report, it's quite apparent that the radio chatter thatnight offered plenty of clues that should have alerted both flightcrews to the danger looming on the runway.

Traditional training doesn't reveal how these clues can be used.Did your instructor school you in the basics of air traffic procedures,to the extent that you know how a controller sets up an arrivalsequence and how to tell just from listening where you fit intothe flow? Serious students of the AIM and readers of the ATC manual(7110.65) can puzzle it all out, but neither publication putsthings into context in terms that pilots (and controllers) canput to use.

With this in mind, consider the LAX accident as an instructiveexample. Departing LAX, the Skywest flight had received its clearanceto taxi to the runway. As is typical of commuter crews, the Skywestpilots probably had a lot of work to do in a short period of timeand to keep things rolling, they asked for an intersection takeoff.

Skywest 569: "Skywest Five Sixty Nine at (taxiway) 45, wewould like to go from here if we can."

Tower: "Skywest Five Sixty Nine, taxi up to and hold shortof 24 left."

Skywest 569: "Roger, hold short."

What was going in the Metroliner cockpit? Probably all that remainedwas to taxi into position, perform whatever line-up checks requiredby the company and await takeoff clearance. So far so good. Butwhat else? At a busy place like LAX, there's constant activityand most of it will be described in some fashion by radio callsbetween aircraft and tower and ground positions. Sometimes movementswill be obvious; sometimes not.

Holding short of a runway is a good place to start forming a mentalpicture of what's happening, what the old time controllers call"the flick." If you're on the tower freq, listen forlanding and takeoff clearances. Who has been cleared to and fromwhat runways? Who's holding short in the departure queue? Whohas been cleared to cross an active runway or told to hold short?Some pilots make a habit of listening to tower on one radio, groundon the other. In the case of Skywest, the clue came from a routineposition report from an inbound flight:

USAir 1493: "USAir Fourteen Ninety Three inside ROMEN (theouter marker for runway 24L)."

In a perfect world, the Skywest crew would have made a mentalnote of this and maybe even discussed the fact that an airplanewas about to land on the runway they would soon depart from. Evidently,they did not.

Tower: "Skywest Five Sixty Nine, taxi into position and hold,runway 24L, traffic will cross down field."

Skywest 569: "'Kay, 24L position and hold, Skywest Five SixtyNine."

Looking a little deeper into what's happened thus far, there arethree situational issues to consider:

Did that mean that the local controller didn't hear the call orwas too occupied to acknowledge? Was she aware of the conflictshe had created on runway 24L or was she just pushing tight gapson departures?

Forty five seconds later, the Metroliner was still in positionon the runway, the downfield traffic had long since cleared. TheUSAir Boeing again called, now well inside the marker. In justshort of a minute, it would have eaten up close to half the distancefrom the marker to the runway threshold. Had the Skywest crewmentally noted the Boeing's position from the initial radio call,they'd have known where it was, even though they couldn't seeit. They could have queried the controller or, if the freq wastoo busy for that, simply taxied clear to sort things out fromthe safety of the taxiway.

Twenty four seconds later, the tower cleared the USAir 737 toland on runway 24L and still the Metroliner stood parked on therunway, awaiting takeoff clearance. Incredibly, another full minutepassed before the tower cleared yet another airplane-a Southwest737-into position and hold on the very same runway, 24L. Wherewas the USAir 737? It must have just passed the threshold or thecontroller wouldn't have cleared the Southwest flight into positionand hold. Had the controller forgotten the Metroliner?

Indeed she had. The USAir Boeing was only seconds from collidingwith the Metroliner, whose crew must have heard the traffic picturedeveloping but either misunderstood its implications and weretoo distracted or indisposed to ask. For its part, the USAir crewseemed unaware of the traffic picture as well. Even though theyhad to call twice to get the tower's attention and would havecertainly heard the tower clear the Metroliner onto runway 24L,the implications simply didn't register.

Later investigation revealed that a contributing factor in thisaccident was the fact that the tower controller's view of theintersection where the Metroliner was holding was obscured. Buteven at that, at a big airport, it's hardly impossible for a controllerto lose track of an airplane in the sea of taxiway and runwaylights at night. This is particularly true of GA aircraft operatingin a terminal where controllers are accustomed to seeing the brightlights and multiple strobes of air carrier aircraft. Whetherin the air or on the ground, a small aircraft is at a distinctdisadvantage when operating into a major terminal and mixing withfaster, heavier traffic. As we've reported before, sequencinga 100-knot airplane into a conga line of airliners doing 140 knotsrequires skill and planning on the controller's part. For thepilot, it may mean flying a much faster approach than normal andperhaps breaking off at the last minute to land on another runway.

You can learn to anticipate this by listening carefully as thecontroller sequences his arrivals. When the controller issuesa heading and an altitude to another airplane being vectored forthe same approach you're headed for, form a mental picture ofwhere that airplane is and what your sequence is relative to thattraffic. If the airplane ahead of you got a 120-degree headingand a descent to 2000 feet followed by an approach clearance,you'll probably get something similar. Or maybe the controllerhas bunched his charges up too tightly on the localizer and issorting things out with vectors and speed control. Don't be surprisedif you get vectored through the localizer for spacing or eventurned out for another approach to a different runway.

On the ground, don't be in too big a hurry to get underway whendeparting. Listen to ground control for a few minutes to forma mental picture of where other traffic is on the airport. Andremember, at a big airport, ground may have trouble seeing youand may not know exactly where you are. If you sense a potentialconflict, speak up and tell the controller exactly where you arein terms he'll understand: "Mooney Nine Eight Bravo is onAlpha taxiway at Charlie One."

Since the LAX accident, some pilots follow the policy of not acceptingposition and hold clearances at night and, even during the day,positioning on the runway at an angle such that traffic approachingthe threshold is clearly visible. To that, we might add the suggestionthat considering jet blast, the run up pad at the runway can bea dangerous place. If you can, run-up elsewhere and be ready atthe runway.

If, by all of this, you think that I'm suggesting you should becomethe keeper of your brother, you're correct. That's far preferableto being in the center of a fireball just past the threshold ofthe active runway.