The live grenades clunk into the cockpit of Foreign Military One.
The M26 is a fragmentation hand grenade made by the United States. Much like the "Pineapple" and "Baseball" grenades, the M26 was given a popular nickname by the army, the "Lemon", by its ovular appearance.
It was used by Colonel Stuart and his men in Die Hard 2.
Die Hard 2
While going to extract drug lord and dictator General Ramon Esperanza from the plane Foreign Military One, Colonel Stuart and his men see John McClane holding the general at gunpoint and attacked him. After McClane killed Thompson, he went to the cockpit. Then the mercenary Kahn barricided McClane in the cockpit and escorted Esperanza out of the plane. After Kahn warns Stuart that McClane is in the cockpit, they fired their machine guns at the cockpit. Then Stuart asked how many M26 grenades do they got and Garber replied that they have three each. Then Stuart, Garber and Kahn started throwing the grenades in the cockpit. After throwing the last of the M26 grenades, Stuart, Esperanza, Garber and Kahn went for cover on their nearby SUV as the grenades went off, destroying the plane. But McClane managed to escape the cockpit with the pilot ejection's seat.