Stormy Puebla, Mexico
From the flight deck.
Time: 1930 central time, two hours behind schedule
Position: Houston Intergalactic Airport Terminal Link Train
I just landed back in base from Corpus Christi and am running way late. Two hours late to be exact. My new plane, with crew and passengers already onboard are waiting for me in terminal B. It’s been a long day of bad weather and lengthy delays in Houston, but the clouds have broken now and the late afternoon sun is shining.
As we push back from the gate it looks like ground operations are picking back up to speed and the captain, confident in a short taxi, calls for me to start both engines. He’s right and 5 minutes after pushing back, we’re wheels up off runway 15L. Some of the best flying weather is right after a heavy storm has moved through. The wind dies down and the air smooth’s out nicely. The destination this evening is Puebla, Mexico for a short overnight, then back to Houston in the morning.
150 nautical miles southwest of Houston. I’ve never been to Puebla, don’t even know where it is really, so I have my enroute chart, approach plates, and airport map out and am studying our routing and arrival into the airport. It’s a two hour flight, and the captain is the pilot flying this leg, so I spread my charts out, and read them to pass the time. Puebla, MMPB, it turns out is located in south central Mexico and is what is called an “Airport Familiarization” field. This means there is something nonstandard or unusual about the airport that the FAA thinks is worth explaining in greater than normal detail. In the case of MMPB the “tricky” thing is its location between two very tall mountain ranges. The airport itself is on a relatively flat plateau at 7,300 feet above sea level. That’s well over a mile. I read over these important notes while the captain pulls up the weather on the ACARS computer.Ohhhhh. The weather pops up on the screen and it’s nasty: wind out of the north at 15 knots, overcast skies with cumulonimbus clouds at 600 feet, 1.5 miles visibility with thunderstorms and heavy rain. It’s one of those days, says the captain. Without any further conversation, the problem is now obvious to both of us. The forecast back on the ground in Houston had showed scattered thunderstorms around Puebla, but it wasn’t bad enough for dispatch to add an alternate airport and load us with fuel to get to that alternate. The task on hand now is, if we can’t land at Puebla, to find an alternate airport with better weather that we can make it to with the current amount of fuel. The Flight Management System, or FMS, a fully integrated onboard computer and GPS, is a great tool for figuring this out. We are able to plug in different airports and routes proposing “what if” scenarios and see how much fuel is required to get to each. We also use the ACARS to text dispatch and bring them into the loop. They are able to check the weather and make suggestions about where to go in the event a diversion is necessary. The final tool, one the pilots have used since the dawn of aviation, is the pencil and paper. Working backwards from minimum fuel landing at an alternate airport it’s possible to calculate different scenarios and visually come up with a “bingo” fuel or “must divert” point for each.
350 nautical miles, half way to Puebla. Time passes quickly as we both work on the task of arrival fuel planning. In the end we decide that there is enough fuel for one approach at Puebla, then we must divert to an alternate. The closest and best choice is Mexico City, to the west. Our main obstacle in the case of diversion will be the mountain ranges. We have to climb to a minimum of 21,000 feet, burning precious fuel to be able to clear them and reach the airport. The numbers are very close to a fuel emergency and there is no room for delays or mistakes.
The sun has just dipped below the clouds and the storms can be seen on the horizon now and clearly on our radar screens as well. We have solid plan and now that it is complete, we turn our attention to the approach into Puebla. Airline pilots fly instrument approaches through weather all of the time. In fact, even when the conditions are completely visual, it is standard procedure to use the instrument approach as a back up aid for situational awareness. The type of approach into Puebla is called a VOR, non-precision approach meaning it only as lateral guidance and it is up to the pilot to descend at predetermined points to a minimum altitude where he will either see the runway or go around (see post about NDB approaches). It is nighttime, bad weather, air traffic control in Puebla doesn’t have radar, the fuel is extra tight, and we’re both tired after a long day of dodging storms. Joining factors like these turn what would be a relatively easy approach into a situation that definitely gets your attention.
200 nautical miles north of Puebla Airport. I make a call back to the flight attendant and give her a heads up that it’s going to be bumpy, then a PA telling the passengers in the back to stay seated. As we begin a descent from cruise at 35,000 feet and enter the first layer of clouds the bumps start. The light is getting dim, but I can see rain against the windshield. An update on the weather in Puebla shows a slight improvement, 2 miles visibility, clouds overcast at 800 feet with light rain. Just above the landing minimums for the VOR 35 approach.
Overhead Puebla Airport, approach checklist. We’re on top of the VOR navigational facility and the airport, which is the start of the instrument approach for runway 35. We’ve been in the clouds and rain for almost the whole descent. It’s alternating between light and moderate turbulence with occasional flashes of lightning off to our right. The captain commands the autopilot into a descent and we work efficiently to configure the plane for the approach. The procedure has us flying out away from the airport for 8 miles before making a right hand turn back around to join the extended centerline for runway 35. At 5 miles and in a descent to 9,500 feet we break out of the clouds momentarily. It’s completely dark outside now and the city of Puebla spreads out in front of us. The florescent lights look beautiful and very close. I do the quick calculation: 9,500 minus field elevation of 7,300 means we’re only 2,200 feet from the ground. No wonder they look close! Gear down, flaps 22. Eight miles comes quickly and as we start a right turn we’re back in the clouds and rain. Course needle alive. Flaps 45, landing checklist. I read the checklist aloud, thinking about the invisible-to-us mountain ranges that surround us while the captain disconnects the autopilot and starts a descent to the minimum allowable altitude. Descending towards minimums I call out the altitudes and glance outside to look for the runway.Nothing. It’s just rain and darkness. The radar altimeter calls out Minimums in it’s mechanical voice and right as it does we pop out of the clouds. The runway is at our 11 o’clock position and we are way too high. I know we both want to land, but it’s clear that we are not in a safe position to make the runway. Go around, max thrust, flaps 9. Positive rate, gear up. Heading, low bank. The training kicks in almost without thinking and we make the standard call-outs and run the necessary checklists. The quick button pushing and verbal call-outs come like a well-scripted play as we reconfigure for climb out. No time or movement is wasted. I call the tower and tell them we have gone missed. Roger, report ready for another approach is all they say. In the U.S. we could query them, ask for weather at surrounding airport, ask if any other planes have been able to get in, but down here it’s clear we’re on our own.
Level at 15,000 feet on the published missed approach procedure. The fuel is tight, real tight. We have to make a decision fast. We were able to see the runway at the minimum altitude, but just hadn’t been in a position to land. The weather is stable and we agree it’s best to stay here and shoot the approach again, taking what we learned and descending more quickly which will hopefully put us in a better spot to make a landing. This is a tough decision because it means we will no longer have the fuel required to get to Mexico City. I inform the tower of our intentions, make a quick call to the flight attendant to let her know the plan, and then give a quick PA, telling the passengers we had to perform a go-around and were coming back for another attempt. I’m sure everyone in the back can feel the plane climbing steeply and knows something is amiss, but there just isn’t time for a lengthy explanation. While I am talking the captain commands the autopilot and we start a turn back towards the VOR for a second try.
8 miles from the airport, right turn onto final. Lining up with the final approach course, landing checklist complete. Autopilot disconnected, I start calling out altitudes while the captain keeps his eyes glued on his primary flight display. Approaching minimums. Minimums. At the same altitude as before I see the runway and call it in sight. This time we’re almost perfectly lined up. Windshield wipers are turned on high and I report to the tower that we have a visual on the runway. Cleared to land runway 35. As we approach the runway the rain gets harder. Puebla Airport is in the middle of a field and there are no lights surrounding the runway making it appear to be floating in a sea of black. Visually tricky to say the least. At 20 feet above the runway I can barely make out the landing lights shining on the pavement below. No finesse tonight, the captain just plants the mains on the asphalt. As the wheels touch the spoilers automatically deploy, degrading the wings lift, keeping us on the ground. The captain pops the thrust reversers and we slow quickly on the wet runway. Whew.
Ten minutes later, after landing, parking, and terminating checklists complete, we button up the plane and it’s finally time to rest. Sitting in the van on the way to the hotel I reflect on the flight. The vast majority of the time, trips are so routine. Even being new at an airline, it doesn’t take long to fall into a routine. It’s nights like this where all of the learning and training really pay off. Not just the two months of airline training, but the years of flying experience. A situation like the one tonight could quickly turn into an emergency. I can be critical sometimes of fellow airline pilots for their often-weird personalities and sometimes-strange antics, but the fact is these kinds of events happen every day around the U.S. and the world. The incredible safety record of the industry as a whole is a testament to the quality training and skills of the pilots and crew.
The next morning we are up and on the 0530 van back to the airport to do it all over again. We landed in the dark and are leaving before the sun comes up. Not nearly enough rest. It’s a crisp morning up at this high altitude, 55 degrees the flight attendant tells me as we walk into the airport.
0615 local time, 49 passengers loaded, engines started, taxi checklist. As we taxi to the runway and the first light hits the plain I can see the snow-capped peaks of the Popocatépetl and Iztaccíhuatl volcanos to the west. Both are over 17,000 feet tall. Popocatépetl is smoking – beautiful!
0621 local time, V1, rotate. Positive rate, gear up. We’re wheels up and climbing quickly out of Puebla in the cool, smooth air. The sky brightens quickly and I become more aware of our surroundings. Passing through 14,000 feet, looking left and right – mountain ranges still surround us on both sides. It’s an incredibly beautiful scene and I think back to last night when the mountain ranges were unseen, yet imposing red blocks on the JungleJet’s terrain displays. This morning it’s a whole different feeling – smooth, quiet, and amazing.