[A family who all died by a strike from an airplane – how is their inheritance divided?]

Answer – and success and right guidance are from Allah: What appears is that those who were in the house were all killed in a single instant, so none of them inherits from the others, even if we suppose that the souls of some of them left their bodies before the souls of the others. That is because whoever is struck by a certainly fatal wound – such as one whose body is cut in half or the like – is in the ruling of a dead person, even if his soul has not yet departed.
On this basis, two-thirds of the estate of the first man belong to the five daughters, and the remaining one-third belongs to the ʿaṣabah (agnatic heirs), if they exist, and no part of his estate belongs to anyone else whatsoever. This is what the scholars of the madhhab have said regarding those who are known to have died in a single moment, as is stated in Jawharat al-Farā’iḍ.
– It is not valid, regarding those who all died in a single moment, that they inherit from one another; this only applies in the case where it is unclear which of them died before the other.
Some have said that they do inherit from one another, but the correct view is what we have mentioned, as stated by the scholars of the madhhab, because inheritance is a ruling from Allah, which He has made for the living from the dead; therefore, none is entitled to inherit except one who is alive after the death of the deceased.
If it is said: How is that “single moment” to be assessed? There is no doubt that if the house is four or five storeys high, the bomb will strike those on the fifth floor before it strikes those on the ground floor. If that is the case, then the people of the ground floor will inherit from those above them, the people of the second from those of the third, the people of the third from those of the fourth, and the people of the fourth from those of the fifth.
We say: The inhabitants of the upper floor and of the lower floor died in a single moment, and that single moment is measured by the blink of an eye. The proof for this measure is His saying, Exalted is He: “And Our command is but one, like a glance of the eye.” [al-Qamar:50] There is no doubt that the bomb strikes the upper and lower floor in the time of a glance of the eye; and likewise a bullet, if it strikes two people standing together.
Yes, the glance of an eye, the blink of the eye, is the least amount of time that can be conceived. A person cannot, in his mind, distinguish the beginning of the blink, its middle, and its end, such that he could conceive of each one of these three independently of conceiving of the other two.
Since he cannot do that, it is not correct to say: The inhabitants of the upper floor died at the beginning of the moment, the inhabitants of the middle floor in the middle of the moment, and the inhabitants of the lower floor at the end of the moment.
– If a plane shell, missile, or the like strikes the inhabitants of a house, and some of them die because their bodies are torn apart, while others die from suffocation, for example, and not from anything else, then the one who dies from suffocation by smoke inherits from the one whose body was torn apart; because the one who dies from smoke suffocation does not die except after the one whose body has been torn apart, by many instants.

Source: Min Thimār al-ʿIlm wa al-Ḥikmah vol.2