SF 330 Exam3

What is the initial priority at an accident site according to ICAO?

Perform Rescue Operations

What is the purpose of securing wreckage during field investigations

Prevent fire, destruction, or theft of evidence

What are some examples of Ephemeral evidence at a crash site

Fuel Gages, Fuel Samples, Ground marks, icing evidence. Instrument gages

Primary reason to move wreckage under NTSB 830,10

To protect life, property, or the wreckage itself

What is the average human tolerance to brief forward G forces

Approximately +9G with proper restraints

What is the load factor formula

Lift divided by weight

When a material returns to its original shape when a load is removed, where can that be be found on a Strain-Stress Diagram

The Elastic Region on a strain stress-diagram

What is a typical signature of ductile facture?

Necking and Deformation before failure

What is the most common cause of GA engine power loss?

Fuel Exhaustion

upon entering a crash site, you see that the propeller of the aircraft is bending forward, what might that indicate?

Possible ____ Power on Impact

Possible high power on impact

again upon entering a crash site, you see that the propeller of the aircraft is bending aft, what might that indicate?

Possible low Power on impact

impact signature of steep angle, low RPM Turbine engine

Major inlet crushing and FOD in early stages

Impact signature of shallow angle, High RPM Turbine engine

Minor inlet crushing, FOD throughout, melted aluminum

What is the Definition of metal fusion in regards to engine investigation

Parent metal hotter than melting point of deposited metal; smooth welded coating

What is the main purpose of an initial walk around at a crashsite?

to gain situational awareness and identify perishable evidence

What is a reason that investigators take photos of fatalities before moving them

they are documenting the original position and injury patterns for analysis

why are witnesses names and locations important, and why should they be recorded immediately?

Witnesses may leave or forget details quickly

Define: Strain

deformation of a material relative to its original length

Define: Stress

internal force per unit area within a material

what does the yield point on a stress-strain curve represent?

The transition from elastic to plastic deformation

What is a typical indicator of brittle fracture?

there will be little deformation and a granular fracture surface

What is the purpose of an engine tear down in propulsion investigation

Its to determine internal condition and identify pre-impact failures

What is a common cause of carb icing?

Temperature drop from fuel vaporization and pressure reduction

evidence of high turbine RPM at impact

Severe rotational damage and blade tip rounding

evidence of low turbine RPM at impact

FOD Damage in early compressor stages only

what is the definition of metal adhesion in engine analysis

Deposited metal forms a rough coating without welding

What is the primary purpose of propulsion investigation?

Determine engine power level and performance at impact

According to the textbook's philosophical introduction to structural investigation, why should 'structural failure' itself never be cited as the root cause of an accident?

structures only fail due to human related factors like poor design, manufacture, or Maintenance

Which term describes a subsonic gaseous combustion that results in a “fireball” during an aircraft impact?

Deflagration

IN the TESTED acronym used for wreckage inventory what does the s represent?

Surfaces

if an investigator find a propeller with tips curled forward, what can be reasonable concluded about the engines status at impact?

The Engine was producing positive power and RPM was high relative to velocity

Which of the following is a characteristic difference between ‘metallization’ via fusion versus adhesion on turbine blades?

Adhesion results in a gritty appearance and the metal can be scraped off with a knife

when examining a metal structure for fire damage , ‘soot shadows’ on the downstream side of a rivet head provide evidence of:

in flight fire expose to the slipstream

According to the textbook, composite structures (like carbon fiber reinforced plastic) differ from metal because they:

have no ‘memory’ and do not retain evidence of load at metal does

what is the primary function of a ‘centrifugal latch’ in a feathering prop?

To prevent the propeller from feathering automatically when then engine is shut down on the ground

in a reciprocating engine, the total temp drop in the induction system can be as high as 45 degrees Celsius due to the combined effects of

Venturi effect and fuel evaporation

Which formula is used to calculate the Propeller RPM (RPM) if the distance between slash marks (D), number of blades (N), and velocity in knots (Vkts​) are known?

RPM=\frac{Vkts\cdot101.3}{D\cdot N} D x N

why does FOD in a turbine engine often produce a ‘multiplier effect’ in the rear compressor stages?

A single object ingested at the front can break off blade pieces that become additional projectiles for subsequent stages

in the investigation of a turbine engine, what is ‘butterflying’ indicative of?

Hydrodynamic stress from water ingestion while the engine was running

True or False: A Fatigue Crack in a metal part can propagate entirely through the cross-seciton before the part fails

False

when handling carbon fire composite wreckage that has been exposed to fire, why is it recommended to wrap it in plastic or spray it with shellac?

to capture and contain the liberated carbon fibers, which are a health hazard if inhaled.