The answer is a definite yes. However there are precautions one can take to lessen the probability of that happening.
d) his seat has slipped and moved away from the controls for some reason and he is not able to reach them again
the plane will likely go down with the weight of the engine pulling the rest of the plane with it. Even if the engine is running perfectly, the inability of the pilot to maintain straight and level flight will mean gravity will take over and the plane will dive towards the ground with an increase in the rate of descent as it drops in altitude.
B. ENGINE FAILURE
If the plane is in perfect condition but all the engines fail, his survival depends on:
C. RESPECT THE WEATHER
Many aircraft incidents (other than from pilot error) are due to weather:
a) a violent storm in a rain cloud may rip the aircraft apart
c) ice may build up in the engine and block air or fuel from reaching it
d) ice may also accumulate on the wings altering their shape and making them lose their aerodynamic lift as well as increasing drag
e) visibility in a cloud may be so poor that the pilot cannot see an obstacle ahead. A billowing cloud may be nice to look at from afar and on a bright and sunny day but it is a totally different scenario from inside it.
I have been in situations where even turning back has to be ruled out because clouds have begun to move in behind me. One then has to fly lower so as to be below the cloud base. This situation often happens in hilly areas because the moist winds move up the slopes and cool as they rise. The moisture then turns into clouds. When faced with this situation,a pilot has to "scud run" meaning he has to weave along the bottom of the valleys. He just prays that there is no dead end or a huge obstacle at the next turn.
D. SKILL AND EXPERIENCE
There are certain emergency situations that a pilot can practice for. These include engine failure, fire during flight or on the ground, wheel brake failure, landing gear failure, electrical failure and other system malfunctions. The steps and procedures to overcome these must be followed precisely and repeatedly until they become second nature to him. When an actual emergency arises, he will automatically carry out the procedure on reflex as there usualy is insufficient time to think anymore.
The pilot himself must be in good condition with sufficient rest and food and appropriately clothed. If flying over water, life jackets must be carried. Survival equipment and first aid kit must also be on board. The aircraft must be in good flying condition with sufficient fuel including reserve in the tanks. The fuel must be checked for possible contamination.
F. A LESSON LEARNT
I had a not so funny experience once when flying with another pilot. It was a flight from KL to Tioman Island and back. I prepared the navlog (navigation log detailing the waypoints, compass headings, altitudes, leg times, etc.) for my outbound flight to Tioman and since the other pilot was to fly the return leg, I assumed that he had done the same for that leg. When we took off to return to KL, he asked me for the heading to fly. I mentally reversed all the compass directions from my navlog and gave him the first heading to follow. I had however absent mindedly given him the reverse of the first heading on my navlog, which was the KL-Kajang leg of 150 degrees, so reversing it resulted in 330 degrees.
It normally takes 34 minutes over the sea in a westerly direction to reach the next waypoint of Kuala Rompin. After thirty minutes out from Tioman we saw the coast some distance away to our left and sensed that something was not right. We nevertheless continued towards the coast and found ouselves over Kuantan,which is 100km to the north of where we were supposed to be. We had wasted some fuel by taking that diagonal track to the coast and now we had to take a longer route than planned to reach KL.
At that time the refueling facility at our home base in KL was unserviceable and all pilots were required to refuel at Subang airport nearby before returning, so we tracked for Subang. All this meant that we had to fly longer than our planned flight and our fuel was running low. At one point the engine sputtered for a number of seconds but then resumed running. We prayed that we really could reach Subang. This we miraculously did.
When the refueler looked into our tanks they were shocked to find no fuel inside. A failure to prepare a simple navlog could have spelt disaster for us. There were no GPSs those days (or they were too expensive then). Today, that incident would not have happened as a GPS will tell you exactly which heading to follow.
Perhaps another lesson learned from this episode is to always double check the information given you by another crew member. Even if one is told "the external checks have been completed", "we have 40 gallons of fuel", or "the minimum safety altitude is 2,500 feet", etc., it is wise to take a second independent look. In the above case, Kuala Rompin is directly to the west of Tioman, so a heading of 330 degrees should have made us question it. Sometimes when we are busy doing something else or in a hurry, simple things like that are missed.