When a plane crashes as tragically and spectacularly as UPS 2976 did while taking off from Louisville, Kentucky, it is normal to look for the cause as soon as possible. And while it’s irresponsible to speculate, what we know for sure is that the 34-year-old MD11 was headed to Honolulu, a distance of just over 7,000 kilometers and a flight time of about nine hours, so the plane would have been heavily fueled.
The McDonnell Douglas MD11 is the latest version of the Douglas DC10, which entered service as a passenger aircraft in the 1970s. Although no longer in production, the DC10/MD11 family of aircraft has had a checkered career in both passenger and cargo air transport.
Credit: nine news
In 1974, a cargo door on a Turkish Airlines plane opened mid-flight, killing 335 people; In 1979, a left engine separated from an American Airlines flight during takeoff, killing 273 people, and many will remember the tragic loss that same year of the Air New Zealand DC10 on Mount Erebus on a flight to Antarctica, although it was no fault of the plane.
Many design flaws have since been rectified, but the aircraft’s reputation suffered and all remaining MD-11s were converted to freighters and serve as cargo-only aircraft.
This latest tragedy has claimed the lives of the three crew members and up to 11 people on the ground, although those figures may change. The herald of aviation reports that the plane was delayed on the ground for up to two hours while work was performed on the number one engine: the left wing engine that, according to video evidence, engulfed in flames during takeoff and separated from the plane during the attempt to take off.
Charging
An engine that is physically detached from the aircraft, although extremely rare, is a design feature of all modern aircraft with engines slung under the wings. They are attached to the wing with “fuse” pins that are designed to fail and protect the wing structure if something catastrophic happens to an engine running at high power, such as during takeoff.
The data shows that the plane reaches around 185 knots, around 340 km/h, which is a typical rotation (takeoff) speed for this type of flight. Takeoff and landing are the most critical moments of any flight and where the safety margins are smallest. These safety margins are analyzed and the risks are mitigated on all flights by the pilots calculating critical speeds. These speeds vary for each flight and depend on environmental conditions such as temperature, atmospheric pressure, wind speed and direction, as well as the actual weight of the aircraft. The speeds are known as V1, VR and V2.
V1 is the speed at which the airplane can accelerate on the runway and subsequently abort takeoff and stop on the remaining runway; in other words, the “point of no return” beyond which, if the takeoff is aborted, the plane will not be able to stop on the remaining runway.
