Aircraft Crash Survival Analysis and Design
SFTY 435
Aircraft Crash Survival Analysis and Design
Final Examination
Return completed exam to instructor by 10:00 PM on 11 December 2012. Send to email:
Name:
Provide an essay type answer for the following questions.
1. Describe the effect plowing can have on crash forces when the impact surface is soft soil.
Earth gouging and scooping of soil occur when the structure makes initial contact with the ground which minimize the acceleration and force levels to which the structure is subjected. Soft soil can cause plowing and rapid deceleration if there is a large horizontal velocity component. A high-speed longitudinal impact into water can also cause high loads from water plowing as water enters through lower nose transparencies. Reducing the earth scooping effects encountered in longitudinal impacts should include a large, relatively flat surface thereby increasing the aircraft's tendency to slide over the impact terrain and by minimizing inward buckling of the fuselage nose or engine nacelle to maintain skid surface integrity.
2. Explain the term submarining in respect to the use of lap belt restraints. What human injuries may result?
This is where the lap belt rides over the pelvic brim and compresses the soft tissues of the abdomen resulting in serious abdominal and spinal injuries. Submarining occurs due to the pelvis rotating under the lap belt, usually due to inappropriate location of the lap belt anchors or due to poor design of the seat bottom or a combination of both. Lap belt only restraints so commonly inflicted serious injuries on users in automobile crashes that the medical community coined a new term, “the seat belt syndrome”, to describe the constellation of injuries caused by submarining under the lap belt. ftp://ftp.rta.nato.int/pubfulltext/RTO/EN/RTO-EN-HFM-113/EN-HFM-113-06.pdf 3. Discuss forward and rearward facing passenger seats and explain which you feel may be an advantage in crash survivability.
Aircraft Crash Survival Analysis and Design
Final Examination
Return completed exam to instructor by 10:00 PM on 11 December 2012. Send to email:
Name:
Provide an essay type answer for the following questions.
1. Describe the effect plowing can have on crash forces when the impact surface is soft soil.
Earth gouging and scooping of soil occur when the structure makes initial contact with the ground which minimize the acceleration and force levels to which the structure is subjected. Soft soil can cause plowing and rapid deceleration if there is a large horizontal velocity component. A high-speed longitudinal impact into water can also cause high loads from water plowing as water enters through lower nose transparencies. Reducing the earth scooping effects encountered in longitudinal impacts should include a large, relatively flat surface thereby increasing the aircraft's tendency to slide over the impact terrain and by minimizing inward buckling of the fuselage nose or engine nacelle to maintain skid surface integrity.
2. Explain the term submarining in respect to the use of lap belt restraints. What human injuries may result?
This is where the lap belt rides over the pelvic brim and compresses the soft tissues of the abdomen resulting in serious abdominal and spinal injuries. Submarining occurs due to the pelvis rotating under the lap belt, usually due to inappropriate location of the lap belt anchors or due to poor design of the seat bottom or a combination of both. Lap belt only restraints so commonly inflicted serious injuries on users in automobile crashes that the medical community coined a new term, “the seat belt syndrome”, to describe the constellation of injuries caused by submarining under the lap belt. ftp://ftp.rta.nato.int/pubfulltext/RTO/EN/RTO-EN-HFM-113/EN-HFM-113-06.pdf 3. Discuss forward and rearward facing passenger seats and explain which you feel may be an advantage in crash survivability.