Delta 1080, KLAS-KATL, 2008-NOV-14. B757-200

Delta's flight 1080 from Las Vegas to Atlanta's Delta Fortress was late in departing because of a "blue-water" leak. Definitely do not want to be spreading blue water all over the place between Las Vegas and the Delta Fortress. Not to mention the fact that icing might cause structural problems, which is not an acceptable risk, being probably non-recoverable at 300+ knots indicated airspeed (about 500 MPH groundspeed). In this case, the Lavatory Service cart was brought back to the aircraft and corrected the problem with the forward lav.

Push-back was about 8 minutes late, 0958 Las Vegas time, taxi to the runway took 18 minutes. Then, with appropriate leading-edge and trailing-edge flaps set, landing lights switched on, take-off power was applied. After a 37-second run in dry, cool air, the flying pilot rotated the aircraft (at the indicated airspeed known as Vr) and lifted off into slightly choppy air. "Rotation" is the process of decreasing lift on the horizontal stabilizer at the rear of of the aircraft, which causes the nose to "pitch up", resulting in an increased angle-of-attack of relative airflow to the wing surfaces. Increased angle-of-attack causes increased lift and the aircraft rises into the air - or is "sucked" into the air. However, increasing the angle-of-attack past a certain point (measured in degrees) causes lift to be "dumped" and the aircraft wing stalls - not a promising flight mode in any aircraft, let alone a big commercial ship.

Interestingly, the speed just before Vr (rotation speed) is V1. V1 is the speed after which the airplane is committed to flying, and stopping the aircraft on the runway after V1 has passed is generally not possible, or if possible carries extreme risk. V2 is takeoff safety speed with one engine out at take-off (which would suck for sure).

Your author does not know if they still call the flight deck or cockpit the "front office", but it should be called the "data center". For the most part, the flight management systems are in complete control of the aircraft just a few minutes after takeoff, say around 10,000 MSL. The flight management computers form a complex, interlinked, highly-available system, with backup systems every which way from Sunday, and if all else fails, there are "old school" manual instruments such as pressure-controlled altimeters, airspeed indicator, standby artificial horizon and so forth. In the business of Sun we work hard at high availability and redundancy, and commercial big-iron aircraft computer systems are wonderful examples of systems redundancy. On big-iron many failures would have to occur to endanger a flight because of the redundancy of systems, and the chances are extremely remote of such a sequence of failures occurring.

Route of flight today is Las Vegas - Albuquerque - Oklahoma City - Tulsa - Memphis and into the Atlanta arrivals (commercial flights are under "positive control" for most of the flight, including the "arrival", but the pilot-in-command can cancel IFR under certain conditions if landing is VFR - which won't be happening on today's flight). Flight time is scheduled for 3:13, not counting any arrival delays due to the low IFR in Atlanta. Conditions have improved since departing Las Vegas, but visibility is still less than 2 1/2 miles in mist and fog. These conditions will almost certainly eventuate an arrival delay. With low IFR, this might be a good time to use the auto-land - also at the discretion of the pilot-in-command. If there is very little wind, it might be advantageous to let the auto-land "ride" the glideslope and localizer all the way to the runway surface.

Flight cruise is scheduled for FL350 - pronounced "flight level three five zero", more or less 35,000 feet, but altimeters are set to 29.92 inches when aircraft fly above 18,000 feet, so FL350 is not exactly 35,000 feet, but with all aircraft using the same altimeter setting, the exactness of altitude does not really matter for separation and safety.

Over two and a half hours into the flight the aircraft began descending toward what looks to be a solid cloud layer.

On the ground, and at home. We were barely minimums on the approach. Great job by the boys up front.

Technorati Tags: B757, Delta Air Lines, IFR, KATL, KLAS, travel, weather, wx

Posted at 03:42PM Nov 14, 2008 by tgardner in Travel  |  Comments[1]