Nobody wants a drone falling on their head, especially if it's a drone large enough to deliver packages for Amazon.

But the e-commerce behemoth clearly sees a future in which bad things happen to good technology, and a malfunctioning drone ought not plummet from the sky.

Better to do it piece by piece.

Amazon has just received a patent outlining a possible plan for "directed fragmentation for unmanned airborne vehicles" used in deliveries.

"The use of UAVs is accompanied by the need for new solutions to various problems, such as service disruptions due to unsuitable weather conditions, equipment malfunctions, and other problems," reads the text of the patent, which the Seattle firm applied for in June 2016 and received Tuesday.

Core to the technology is a "fragmentation sequence" that the drone constantly updates with an eye to flight path, flying conditions and what lies in the terrain below.

"Terrain topology information or data can identify certain preferred locations for dropping one or more of the components of the UAV," the patent document says.

"For example, the terrain topology information can identify bodies of water, forested areas, open fields, and other locations more suitable for dropping components of the UAV if or when flight operation errors, malfunctions, or unexpected conditions occur.

"Terrain topology data can identify the locations and boundaries of residential, commercial, and industrial buildings and developments, highways and surface streets, parking lots, stadiums, schools, recreational areas, and other artificial features."

What might cause an Amazon delivery drone to need to divest itself from itself, in parts?

"Unexpected heat, cold, wind, rain, hail, high or low ... pressure regions, or other meteorological conditions," according to the patent document.

"High winds may make it difficult or impossible to control the flight operations. High heat may also result in failure or malfunction of the battery ... leading to loss of thrust provided by the rotor system. Other components ... such as the rotor system, flight control computer, flight sensors, or other components, can unexpectedly malfunction or fail for various reasons."

The idea behind the patent is not to let the drone dismantle itself until there's nothing left.

"During the fragmentation sequence, one or more parts or components of the UAV can be released. In doing so, the weight, speed, air drag coefficient, and other factors related to the UAV can be altered. At the same time, the momentum and trajectory of the UAV are also altered.

"According to aspects of the embodiments, the fragmentation sequence is tailored to modify or alter the manner in which the UAV descends, to control the descent in a preferred, controlled manner," the patent document says.

The drone's systems would allow it to control where the parts fall, so they would "descend in a calculated or estimated trajectory to the preferred locations."

The illustration accompanying the patent indicates those locations would include a pond and a tree. The drawing also appears to show the drone dropping the cargo into a tree.

Parts could be released using latches, hooks or springs, or "small explosive charges" or compressed gas.

There's attention to cost, among other factors, in what gets jettisoned.

"The fragmentation sequence engine can select the order based on various factors, such as the replacement value or cost of the components, the air drag coefficients of the components, the weight of the components, the purpose of the components, and other factors," the patent document says.

However, just because Amazon patented this system -- which also seems unsuitable for urban centers -- that doesn't guarantee it'll go into action. Still, the company recognizing the possibility of "catastrophic failure" of a delivery drone indicates that some solution is needed before Amazon starts delivering goods via drones.