By now, just about every pilot has heard about the ill-fated Atlas Air Flight 4241, in which the Boeing Dreamlifter (a modified 747 cargo aircraft), landed at the wrong airport while attempting to land at McConnell Air Force Base (KIAB) in Witchita, KS. The aircraft landed inadvertently at the Colonel James Jabara airport (KAAO) 7 miles to the north of McConnell AFB. To make matters worse, Jabara’s longest runway is only 6101 feet long, not normally long enough for the Dreamlifter, and the aircraft couldn’t maneuver on the narrow runway without help, so Boeing had to send a tug to move the aircraft.
The Dreamlifter was able to depart uneventfully the next day:
For a commercial pilot at the level of the pilots of 4241, the outcome is no doubt devastating. There’s an NTSB investigation under way, and apparently the FAA is investigating as well. The incident could certainly lead to certificate actions and/or dismissal from Atlas Air. If the pilots are let go, it could be very difficult for them to find new employment at their current level. The pilots are no doubt devastated.
Before analyzing what happened, it’s worth listening to the exchange between flight 4241 and McConnell tower just prior to landing. It gives some hints about what happened, including the apparent confusion of the pilots after the landing. Here’s the audio, in its full cringe-inducing glory:
I’ll put the full transcript in another post (with helpful snarky commentary), but the first bit is the relevant part:
Atlas 4241: Good evening, McConnell tower. Giant 4241 heavy is on the vis – er, GPS, RNAV GPS approach 19 left.
KIAB tower: Giant 4241 heavy, McConnell tower. Check wheels down. Runway 19 left, wind 140 at 4, cleared to land.
Atlas 4241: Clear to land, runway 19 left, wheels down. Giant 4241 heavy.
KIAB tower: Giant 4241 heavy, check wheels down.
Atlas 4241: Giant 4241, go ahead.
KIAB tower: Giant 4241 heavy, check wheels down and expect a mid-field turnoff taxiway Delta.
Atlas 4241: Giant 1440 – 4241. We might – We’ll get back to here momentarily, we’re not on your approach.
KIAB tower: Giant 4241 heavy, McConnell is 9 miles south of you.
Atlas 4241: Uh, yes sir. We just landed at the other airport.
Atlas 4241: And McConnell Giant 4241.
KIAB tower: Giant 4241 heavy go ahead McConnell tower.
Atlas 4241: Uh yes sir – uh, apparently we’ve landed at B E C.
KIAB tower: Giant 4241, verify you’re on the ground at Beech Airport?
Atlas 4241: We think so.
So at this point, while trying to land at KIAB, they’ve actually landed at KAAO, but think they've landed at KBEC. Or maybe not. The pilots realize something has gone terribly wrong, but it will take them another few minutes to figure it out.
So what did happen? Using data from FlightAware, I’ve pieced together the most likely scenario. 4241 was flying the RNAV (GPS) RWY 19L approach, shown here:
and the FlightAware data:
At 10:16 pm EST, 4241 was 6 nm east northeast of the WITBA waypoint. It had been cleared direct to WITBA, and the data shows that it was in fact flying directly toward the waypoint. WITBA is an initial approach fix (IAF) for the RNAV (GPS) 19L approach, so that makes sense. Furthermore, the altitude is 4000 ft, which is the minimum altitude to cross WITBA, so everything seems OK at that point. There's then a 4 minute gap in the data. At 10:20 pm EST, 4241 is on the segment between the IAF (WITBA), and the final approach fix (FAF) WARUN. The minimum altitude along that segment is 3000 feet, but 4241 has already descended to 2300 feet, 700 feet below the permissible altitude. At this point, it’s still 3.75 nm north of the FAF, and 1.45 nm north of the KAAO runway 18 threshold, and 879 feet above the elevation of KAAO. That would put the aircraft on a very high (5 deg) glideslope for runway 18 at Jabara. There’s no more data after that point.
It’s not entirely clear what happened, but here’s a plausible scenario: After passing the IAF at WITBA, the pilot began a descent, nominally to 3000 ft. The pilot knew he was on an RNAV (GPS) 19L approach, because he read back the clearance that said so, but may have been thinking about a visual approach. Indeed, the recording shows that he started to say “visual approach” rather than “RNAV (GPS) approach”. At some point, he saw the runway environment of KAAO, which has the same alignment, more or less, as KIAB. Seeing what he expected to see, he discontinued the instrument approach, and flew the approach visually. It was only much later, after he landed, that he realized that he was still short of WARUN, much less KIAB.
The pilot was cleared to fly an RNAV (GPS) approach. That approach clearance requires that he maintain at least 3000 feet until passing the FAF, WARUN. Had the pilot flown the instrument approach as required, there would be no possibility of mistaking KAAO for KIAB, since the approach required him to fly at 3000 ft MSL over KAAO, 1600 above ground level. Upon reaching WARUN, neither KAAO or KBEC could be mistaken for KIAB. So it appears that the pilot simply neglected to fly the approach he was cleared to fly, and instead flew what was essentially a visual approach. Unhappily for him, there are two airports with the same runway alignment along the final approach course. To make matters worse, he failed to have the situational awareness to understand that he was 7 miles short of the correct airport.