write:2. BASIC StEPS. Step one in a reciprocating engine investigation is to assemble everything that is known so far about the accident. This includes witness statements radio transmis

they always show evidence of rotation as that is their normal wear pattern. Second
there is nothing on the recip that consistently captures evidence of what was hap-pening at impact. That is why so much attention is paid to the propeller. It provides at least an indication of what was going on (see Chapter 11).2. BASIC StEPS.Step one in a reciprocating engine investigation is to assemble everything that is known so far about the accident. This includes witness statements
radio transmis-sions and the basic circumstances of the accident. Is there any positive evidence that the engine was running — or not running? Did anyone hear it? Be cautious in accepting at face value statements about what the engine sounded like. Statements like
“The engine was cutting in and out
” or
“The engine was running rough
” need verification. An idling engine can sound like that. Do the accident circumstances fit the common scenarios for engine failure-type accidents? Engine failure on ap-proach or landing
for example
is not a common accident cause as the engine(s) are already being operated at low power and the aircraft is already in a nose low descending attitude. If loss of power occurred
it is usually manageable. On the other hand
a takeoff accident is much more likely to be related to engine power. Here
full engine power is needed and a sudden loss of power can be difficult to manage.Second
determine what you really need to know about the engine. Was it completely stopped (propeller feathered or stopped?) Was it turning at something less than full power? Was it turning at something close to full power? Let’s ap-proach this logically.3. ComPLEtE EnGInE FAILuRE oR InFLIGHt SHutDoWn.If the propeller was feathered
the engine was not rotating at impact and the feathering occurred at some point prior to impact. The pilot either deliberately shut-down the engine and feathered the propeller due to some cockpit indication or the engine failed and the propeller feathered itself because an auto-feather circuit was installed and armed. Given that this all occurred in flight with the engine above 600-800 RPM
examination of the propeller should tell us which of these occurred.If we conclude that the pilot deliberately shutdown the engine and feathered the propeller due to cockpit indications
we ought to attempt to determine what those indications were. We’ve got several cockpit instruments and switches to help us (see Chapter 14 for instrument investigation techniques).If the engine merely failed (not deliberately shut down)
then we are not likely to find much evidence of the cause in the cockpit. In these situations
a large percentage of engine failures are related to fuel; or lack of it. We should start with a routine check of the fuel system.A. WAS tHERE FuEL on BoARD? We can investigate this indirectly by considering fuel consumption and the duration of flight since last refuel-ing and directly by examining the tanks if they have not been destroyed.