Why is the drogue parachute of a military plane jettisoned on the runway? Why not drag it to the parking area for safe removal, inspection, and repacking?
For several reasons.
First to protect the drogue from damage by scraping on the pavement
second to prevent it from becoming snagged on nearby objects
third to prevent metal components on the drogue from hitting and damaging the tail of the aircraft,
- and fourth to make it easier to taxi back to the ramp without the need for higher power setting to overcome the drag and prevent damage to the drogue from this jet blast.
One downside to jettisoning the drogue at a lower speed (< 40 kts) is that it now creates a FOD hazard on the runway and requires a waiting cleanup crew to retrieve it before another recovery is possible.
Anyone who jettisons a DRAG chute on the runway will be roundly jeered by his mates, ops in the tower, "guest lecturers" (your flight lead, boss, etc) and ground crews. Chutes are jettisoned OFF the runway at a point and place designated not to close the runway for FOD and to allow retrieval by recovery crews. That being said, there MAY be a reason in some operations for dropping the drag chute prematurely. There is usually a fair size "ramp" or "apron" immediately off the runway where this chore is done, without screwing up the taxiways to and from the RW/parking. It is often a "de-arming" area, where safety pins and other securing devices are installed on combat aircraft with ordnance aboard.
A DROGUE chute is one that helps extract a main chute from a pre-packed storage container (drag chute bay, parachute container in ejection seat, or seat/back/chest pack, etc).
There is no discernible drag from a drag chute at low speeds, but you can't count on the exhaust to keep the chute reliably inflated, off the ground, or from becoming entangled in lights, equiptment, etc on the way back to the chocks. The recovery crews WISH the pilot could bring it back to the parking apron....
- Chutes are jettisoned after clearing off the runway in the designated area.
- The reason for jettisoning chutes is so that they do not scrape on the operating surface and wear off.
- Dragging them along may result in damaging the lights or other objects.
- Also it is an additonal weight being carried by the aircraft, which generates drag and slows down taxy back to the apron.