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N991MS » Blog Archive » Spring Turbulence

Spring Turbulence

We are westbound over Santa Rosa, NM, on the way to Albuquerque. Flying at 6,000 ft MSL, which is just 1,000 ft AGL, we encounter just light turbulence instead of the moderate turbulence above us. But it is time to start the climb to 12,500 ft MSL to clear the Sandia Mountains to the west. As we try for this, we run immediately into moderate turbulence and thus go lower again. Now what?

The day has started nice enough. With perfect spring weather of early May, we lift off from Aero Country at 7:00 am in our Zenith 601HDS, N314LB. There is some headwind shortly after takeoff, but it diminishes as we climb to 4,500 ft MSL. After 3.3 hrs, we reach Plainview in West Texas. This is always a fun stop. The folks are friendly - they once helped replacing a failing battery with a WalMart motorcycle battery - and the fuel is cheap. Who would have thought that less than $5/gal one day would be considered cheap!? Another reason to love Plainview are the two runways, in case the wind blows unexpectedly from the east or west. There is plenty of wind as we land, but not gusty. After refueling, we ask the FBO ”Do you ever have a no-wind situation?” The unexpected answer is ”We have it right now.”

A quick call to the FSS reveals that from Hobbs, NM, westward, moderate turbulence is expected up to 16,000 MSL. A brief review: ”light” turbulence means that there are a few bumps, ”moderate” says that there can be very significant bumps but not severe enough to make the flight uncontrollable, and ”severe” tells that turbulence may invert the plane. For us fliers of light aircraft, ”moderate” is clearly the upper limit for turbulence. As we found out in earlier trips, ”moderate” can be a very nasty flight where stick and rudder barely manage to keep the plane under control. Sure enough, as we reach Hobbs, the turbulence sets in. We reduce altitude to 1,000 ft AGL, and luckily the turbulence diminishes and becomes light. Actually, the flight is most enjoyable. There is lots of detail to see, and the sensation of speed is increased. By the way, this points out a simple rule: If your plane seems too slow, than either build an RV or fly lower. Since we love flying lots of hours, flying lower is our choice.

As we pass Santa Rosa, we become concerned about the turbulence above us. Without question, we must climb a lot before reaching Albuquerque to clear the Sandia Mountains. Today this is particularly important since the winds aloft are from the southwest, and we approach the mountains on the lee side. The rule of thumb is, if the wind component at right angle to the mountain ridge exceeds 25 kts, then crossing the mountains from the lee side is very dangerous. If the wind component is below that critical value, then stay at least 2,000 ft above the highest point. For our route, the highest point of the mountains is about 9,000 ft, so going westbound, we should climb to 12,500 ft. Approaching the Sandia Mountains, we keep on probing the turbulence above 1,000 ft AGL. All attempts end with us going lower again. There are strong indications of the turbulence above us, too: High cirrus clouds that look torn if not shredded. Very strong winds are blowing up there.

Near Clines Corner, about 50 nm east of Albuquerque, the torn cirrus clouds stop and there is clear sky ahead. Maybe this is the end of the turbulence, too. We climb a bit to check it out and discover that indeed the turbulence is not as bad as before. In fact, within another 20 miles, we are in smooth air. How nice! We call Flight Watch to tell them about this change, and they are pleased to get the update. At 12,500 ft MSL we cross the Sandia Mountains and see the Albuquerque International Airport below with its multiple runways. The Class B space only goes to 9,500 ft MSL, so we are way above it. Our destination is the Double Eagle airport just west of the Class B space. The AWOS at the airport has some bad information. The winds are 19 kts gusting to 25 kts, with direction shifting all the time. In fact, the AWOS just gives a range for the direction. Fortunately, Double Eagle has two runways, and we opt for the one that most likely will be a good choice given the shifting winds. Going from 12,500 ft MSL to 6,800 ft pattern altitude takes a steep descent. But here the 601 HDS shines. With the descent rate pegged at 2,000 ft, the plane does not exceed 110 kts. No doubt, this airplane has little problem with overspeeding!

In the pattern and even on final, we flip back and forth between UNICOM and AWOS. Amazing how much the wind is changing direction. But then, during the last 50 ft of descent, the gusts lessen a bit and we manage to land rather well. This is a first visit for us at that airport. The folks are helpful. As agreed on in a phone call the day before, we can put the plane into a large hangar. This is a must for Albuquerque, where a sand storm can develop at any time.

Albuquerque is a nice city to visit. My daughter Ingrid lives there, and we have a great time. On Sunday she and I fly sightseeing to Taos and back. This turns out to be a great idea, and I highly recommend that side trip if you are in the area. The key idea is to leave early in the morning and plan to come back not later than 2 pm. We take off into smooth air. Just north of Albuquerque, balloons are taking off into the morning air. There is a slight wind from the north, so the balloons drift south. We approach the balloon takeoff area from the north at 500 ft AGL, which is legal since this is not a densely populated area. In fact, there are hardly any houses at all. Since we are so low, we see the rising balloon against the clear sky, a beautiful sight.

We follow the Rio Grande, but at times meander to the east into the sloping mountains. We bypass the airspace of the Santa Fe controlled airport, which rises from 6,300 ft MSL to 15,100 ft MSL. Why on earth did they give the airport such a huge cylinder of controlled airspace? As we approach Taos, the Rio Grande gradually disappears into an impressive gorge that we explore for a while. Then comes the easy landing at the Taos airport, which sits on a mesa and has a long runway. It has taken us 1.8 hrs to fly from Albuquerque to Taos, a distance of less than 100 nm.

A Learjet lands. It is the CEO of some company and his pilot, an amiable woman. As the CEO is picked up for a weekend of fishing, we talk with the pilot about flying the jet into and out of the Taos airport. ”Landing is easy”, she says, ”but the takeoff is marginal.” She explains why. ”The Learjet has rather weak brakes. Even at the lower density altitude of a cool morning, the Taos runway is just long enough to abort the takeoff run if necessary and stop before the end of the runway is reached.” No such problem with the 601 HDS. The plane leaps into the air despite 9,500 ft density altitude. This time we stay on the west side of the Rio Grande, passing near Los Alamos and Bandelier National Monument. Again, there are impressive vistas. The landing in Albuquerque is nice and easy, since we are returning around noon.

The next day, it’s another beautiful trip going from Albuquerque south to visit Lynn and Philip Welsch in Casas Adobes near Silver City. Philip has warned me that the winds can pick up by 10 am so much that landing can become difficult if not impossible. Heeding his advice, we lift off at Albuquerque before 7 am for the 2 hr flight. The plan is to follow the Rio Grande and enjoy the scenery, and later jump across the mountains to the west and descend into the valley of Casas Adobes. The part of following the river and enjoying the scenery works out well, since we pick 1,000 AGL and the air is smooth. Higher up it is predicted to be moderate turbulence. Opening the flight plan, the FSS asks us to assist with testing 121.5 stations at Las Cruces and Silver City. We tune in 121.5 and listen to an unusual amount of traffic where the FSS test various outlets, enlisting high-flying commercial jets and low and slow guys like us. Not all tests work out well, as now and then a signal is declared to be clear but weak.

At the latitude of Silver City, it is time to climb and turn west. This works well until we reach the mountain range, with peaks around 10,000 ft. Since the wind is out of the west, the plane develops a sink rate that cannot be arrested with full power. We turn away from the mountain and climb outside the downdraft. Once we are at 12,500 ft, we cross the mountain. Below is Casas Adobes. Its runway at 5,800 ft MSL looks tiny from 12,500 ft MSL, but grows a bit as we spiral down. Flying along the runway at pattern altitude, a wind sock at midfield indicates wind from the north. To the east and west of the runway, the terrain rises rather rapidly, something to think about as we turn to get back for the landing. But a year ago a landing in Utah taught a lesson in this regard, so we climb before turning back to the airport. The landing is in smooth air.

Lynn and Philip Welsch’s house/hangar is maybe 300 ft from the runway, so we just taxi up to the house. An hour later the winds pick up, and by 11 am we have a 40 mph crosswind for the runway. Surely we would not want to land under those conditions.

The stay with Lynn and Philip Welsch is wonderful. They are terrific hosts. During the course of the next three days, we visit the Gila Cliff Dwellings, a National Monument. This is an internationally known site of Indian adobe buildings constructed into mountain caves around 1200 AD and deserted shortly thereafter because of drought. The buildings and setting are at least a match for the more popular Mesa Verde. Altogether, this is beautiful Southwest Country.

It is time to say good-bye. The forecast is for a tailwind at 20-25 kts, which turns out to be correct and blows us to Aero Country. The engine is throttled back, yet the trip takes only 7 hrs of flying. Not bad, considering that this is done with just 24 gal of fuel.

A good question to ask at the end of a plane trip, is: What did we learn? The answer here is: Spring time in New Mexico can have terrific winds at any time of the day, with the worst starting in early afternoon. Flying low can be an excellent solution if terrain permits it, and departing at sunrise and stopping for the latest around 1 pm is another good idea.

One Response to “Spring Turbulence”

  1. digitalnut Says:

    excellent article Klaus.

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