Tag Archives: San Francisco International Airport

And it ain’t much.

Speculation this early after a plane crash is nearly always incorrect because of insufficient information, yet speculation abounds on Saturday’s crash of Asiana Airlines Flight 214.  You could write a book on what we do not currently know — the cockpit crew interviews, the information from the “Black Boxes,” witness interviews, crash damage analysis, etc., etc., etc.

Here’s what we do know about the crash:  Asian Airlines Flight 214, a Boeing 777-28EER operating with two Pratt & Whitney PW4090 engines (an important detail as you’ll see in a moment), landed short of Runway 28 Left at San Francisco International Airport (SFO).  Aboard Flight 214 were sixteen crew and 291 passengers for a total of 307 POB (Personnel on Board).  The aircraft apparently struck the seawall located short of the approach end of Runway 28L.  The vertical and both horizontal stabilizers were sheared off and lay upon the runway just short of the landing threshold line and threshold markings (see images below).  Landing gear parts lay between the threshold markings and the touchdown zone markings.  The aircraft skidded off the runway to the left and at some point caught fire.  Two passengers (both schoolgirls) died, their bodies both found outside of the wreckage (not reported is if the bodies were still strapped to their respective seats).  Injuries were sustained by 181 people.  Of those 181 people, forty-nine are deemed in critical condition.

Here’s what we know leading up to the crash:  The weather at SFO was VMC (Visual Meteorological Conditions) with blue skies, few clouds, good visibility, and light winds reported.  The Runway 28L ILS (Instrument Landing System) was out of service, so the pilots would not have had a Glide Slope instrument indication in the cockpit to advise them of their angle of descent.  They would however (provided it was working, which appears to be the case) have a good view of the Runway 28L 4-Light Precision Approach Path Indicator (PAPI), which was set to visually guide pilots onto a 2.85° glide path (slightly below the more normal three-degree angle most commonly used).

Here’s some expert Air Traffic Control speculation:  Since the weather was clear and the ILS was out of service, it is reasonable to assume that Asiana Airlines Flight 214 was conducting what is known as a Visual Approach (See definition below) to Runway 28L at the time of the accident.  If that is the case, the cockpit crew would have been responsible for maintaining the proper descent angle to the runway using visual references (including the PAPI previously mentioned) and other on-board, non-ILS derived information (radar altimeter, etc.).

Visual Approach Definition (U.S.):  An approach conducted on an instrument flight rules (IFR) flight plan which authorizes the pilot to proceed visually and clear of clouds to the airport.  The pilot must, at all times, have either the airport or the preceding aircraft in sight.  This approach must be authorized and under the control of the appropriate air traffic control facility.  Reported weather at the airport must be ceiling at or above 1,000 feet and visibility of 3 miles or greater

What we know about the Boeing 777:  Quite simply put, this aircraft is one of the safest in existence.  Over 1,100 have been built since 1993, and the aircraft remains a bestseller for Boeing to this day.  There have been a total of only three “hull losses” (meaning the aircraft was a total write-off) involving the Boeing 777 and only one previous fatality.  The previous two hull losses and one fatality were:

• September 5, 2001 — Denver International Airport:  British Airways Flight 2019, Boeing 777-236, suffered a mishap during a refueling operation at Terminal Gate A37.  Minor, reparable damage was sustained to the left wing and the left engine cowling and thrust reverser.  A ground crewman died six days after the accident from injuries sustained during the fire.
• January 17, 2008 — Heathrow Airport, London:  British Airways Flight 38, a Boeing 777-200ER, landed short of Runway 27 Left.  That may sound familiar, but keep in mind those Pratt & Whitney PW4090 engines I told you about above.  We’ll get back to that in a moment.  Forty-seven people were injured; there were no fatalities.  The aircraft was destroyed.
• July 29, 2011 — Cairo Airport, Egypt:  Egyptair Flight 667, a Boeing 777-200 pushing back from Gate F7, Terminal 3, experienced a fire in the cockpit.  The twelve crew and 307 passengers deplaned with no injuries.  The aircraft was irreparably damaged.

So, what’s so important about those engines, and why is speculation so prone to error at this point?  Here’s why:  Already at least one major news organization, The Daily Mail, has had one blazing headline pronouncing, “Crash landing at San Francisco mirrors that of BA Boeing 777 crash at London Heathrow five years ago.”  Uh . . . no, guys, it really doesn’t.  The only similarity is that both aircraft impacted short of the runway and skidded onto it.  Beyond that the crashes are in no way “mirrored.”

The Daily Mail speculates that, as in the British Airways 38 crash, there was something amiss with the engines on Asiana 214.  The problem with British Airways 38 (and two other loss-of-power incidents involving the Boeing 777) was eventually tracked down to a flaw in the design of the fuel/oil heat exchanger used in the Rolls-Royce Trent 800 engine.  That flaw allowed ice slush to reduce fuel flow to the engines, allowing enough fuel to keep them turning but restricting fuel needed to apply go-around power (powering up the engines to sufficiently and safely lift the aircraft back into the air after an aborted approach to the runway).  That component has since been redesigned and flown without incident ever since that redesign was incorporated into existing fleets and subsequently manufactured aircraft.  The Pratt & Whitney PW4090 has never displayed any such problem.  Ever.  If there was an engine problem with the engines on Asiana 214, it is unlikely to have affected both engines simultaneously and only one engine is needed to abort a landing.

What to watch for (and what to ignore) in the coming investigation:

• It’s far too early to speculate on the possibility of pilot error, but right now that appears to be the focus.  Did the crew wait too long to initiate a go-around (unknown at this time, but it appears a go-around order was given only seven seconds before impact)?  Did the aircraft come in too fast and/or too low (no evidence to date, but eyewitness accounts and video seem to show that the aircraft was far below normal height on the final approach)?  Were the pilots under- or overcorrecting from initially coming in too high (no indication of this as yet)?  These answers will come from the crew interviews and the Digital Flight Data and Cockpit Voice Recorders (DFDR and CVR — the orange colored “Black Boxes” about which you hear so much).

• There’s been some online speculation that the left wing flaps appear to have not been extended.  Sorry guys, but you’re incredibly wrong here.  The slats are obviously extended so the flaps would have been as well.  Additionally, the right side flaps can clearly be seen in the extended position.  And if the right side were somehow extended while the left side flaps remained retracted, the Boeing would have experienced an uncontrollable roll to the left such as happened in the case of American Airlines Flight 191 at Chicago O’Hare on May 25, 1979.  This is not a retracted flap/slat issue.  If it is a flap/slat issue, it’s related to insufficient extension of the flaps and slats for that phase of flight, which is highly doubtful considering the warning devices aboard modern aircraft.

• Could this be a simultaneous engine problem?  Such things have occurred in the past, but such events are exceeding rare and have usually been attributed to outside influences (ingestation of birds, hail or extremely heavy precipitation, volcanic ash, etc.).  The few mechanical events on record were either poor design (see the Roll-Royce Trent 800 discussion above) or maintenance errors (Eastern Airlines Flight 855; Miami International Airport; May 5, 1983).  So far the CVR shows no indication of an engine malfunction, and the pilot is heard calling for go-around power as if the engines were operating normally.

For those with a fear of flying I would ask that you keep in mind the number of survivors in this otherwise devastating crash — over 99.3% of those aboard got out, and most of them with either no or only minor injuries.

As for the rank speculation you’re hearing so far, take all that guesswork from the rank amateurs and wannabe pilots for what it is — the rantings of people who will gladly (and in most cases anonymously) point fingers now but who won’t retract unwarranted accusations later if and when they’re proven wrong.

About the author’s credentials:  R. Doug Wicker spent over thirty-four years as an Air Traffic Controller for both the U.S.A.F. and F.A.A.  During his time in the F.A.A. he was also trained in accident/incident investigation for his duties as a Quality Assurance & Training Instructor (QATS) for El Paso International Airport from 1987 until 1996.  Mr. Wicker is the author of The Bombing of Pan Am Flight 103 as well as three as yet unpublished novels on aircraft sabotage.