When used correctly, a strategic bomber is dangerous only to the enemy. However, any violation of the instructions leads to risks and dangers for the flight and technical personnel. Security issues are always given great attention, especially when it comes to complex and capricious techniques. For example, during the operation and maintenance of the Convair B-58A Hustler long-range bomber, American specialists had to monitor a number of factors and follow certain safety measures.
Useful but dangerous
For its time, the B-58A had outstanding tactical and technical characteristics and combat capabilities. He could break through the air defense of a potential enemy, drop special ammunition on the target and safely return to base. Maximum speed exceeded 2100 km / h, combat radius - more than 4100 km, combat load - 8,8 tons in a special container.
High performance was ensured by the use of a number of modern technologies and the latest types of avionics. So, four General Electric J79-GE-5A turbojet engines with a maximum thrust of 4536 kgf and afterburner 7076 kgf were responsible for flight performance. Flying and hitting targets were performed using the Sperry AN / ASQ-42 sighting and navigation system, which included several different instruments. In case of an enemy attack, there was a 20-mm automatic gun with a radar sight.
The use of all these new products gave certain advantages, but led to negative consequences. Complex and expensive aircraft made special demands on the training of staff. In addition, some of its components could pose a risk to people and equipment. Therefore, for safe operation with the aircraft, simple rules should be followed. In particular, it was recommended not to get into the danger zones around the aircraft.
A number of risks and dangers of the B-58A for ground personnel were associated with its power plant. Four GE J79-GE-5A engines created several hazardous areas around the aircraft with different “damaging factors” and risks. Getting into some of them threatened, at least, with injuries.
In nominal mode, the J79-GE-5A engine consumed 77 kg of atmospheric air per second (approx. 60 cubic meters). As a result of this, a powerful stream was formed near the air intakes, capable of picking up one or another object. For this reason, when the engines were running, it was forbidden to be in the hemisphere in front of the air intake in a radius of 25 feet (7,6 m), as well as in an area 5 feet (1,5 m) deep behind it. The location of the engines was such that the hazardous areas of the air intakes were blocked and combined. The general area was wider than the aircraft, and only the nose fairing did not fall into its limits.
In maximum mode, the temperature in front of the turbine reached 930 ° C. At the same time, a supersonic gas stream flowed out of the nozzle. When you turn on the afterburner, the temperature and gas velocity increased. Running engines formed a continuous danger zone behind the aircraft with a depth of 40-75 m. In this regard, it was recommended to build gas baffles near the parking lots.
At a distance of 25 feet, the speed of the jet stream exceeded 260 m / s; temperature - approx. 220 ° C. At 100 feet, the speed dropped to 45 m / s, and the temperature dropped to 65 ° C, which was still a danger. When using afterburner, the gas velocity at 25 feet from the nozzle reached 460 m / s, the temperature - 815 ° C. At a distance of 100 feet, these parameters were reduced to 76 m / s and 175 ° C, respectively. According to calculations, the engine in all modes was dangerous for people and equipment at distances up to 70-75 m, which required appropriate precautions.
When operating the J79-GE-5A engines, especially when starting and switching between modes, there was a non-zero risk of destruction of the starter or turbine. In such an accident, debris could fly apart from the engine nacelle within a narrow sector. Each engine had two such annular zones.
The obvious problem was the noise of running engines. The operation manual required the constant use of personal protective equipment. Failure to do so would result in permanent hearing loss. However, in this regard, the B-58A was no more dangerous than other aircraft of its time.
The AN / ASQ-42 sighting and navigation system included several systems for various purposes, some of which could be dangerous. Microwave stations threatened humans, electronic devices, and ammunition and fuel storage facilities. In this regard, additional zones around the aircraft were determined, which were subject to certain restrictions.
The B-58A carried several radar systems for various purposes. We used the AN / APN-110 Doppler navigation locator, the AN / APN-170 station for enveloping the terrain, the AN / APB-2 bomber sight, and the MD-7 radio sight to control the gun mount. Some devices were located in the nose of the fuselage, others - at the bottom of the tail and at the base of the keel.
When using nasal radars, the hazardous area was the 180 ° front sector. Operating radars were dangerous for people at a distance of 100 feet (30 m), for fuel - up to 200 feet (61 m). The MD-7 radio sight had a different power, which is why a less wide sector of the rear hemisphere with a radius of 160 feet (48,6 m) was considered dangerous for humans. For fuel, twice the distance was set. The tail radio altimeter emitted in the zone in the form of a cone with a base with a diameter of 8 feet (2,4 m).
Risk on Wheels
Due to the specific aerodynamics, the B-58A bomber was distinguished by high take-off and landing speeds. When touching the landing strip, the speed was 300-330 km / h. This led to high mechanical and thermal loads on the wheels and the brake system of the main landing gear. There was a risk of fire or explosion of tires - with understandable unpleasant consequences. By the time the nose strut touched, the speed was falling, and the loads on its wheels were lower, which made them safer.
After landing and taxiing into the parking lot, the wheels of the main supports should be closed with special screens capable of withstanding the explosion. If they were absent, appropriate safety measures should be followed and not approach the chassis. The lateral sectors 90 ° wide (45 ° forward and backward relative to the axles of the wheels) within a radius of 100 feet were considered dangerous. It took 30 minutes to cool the chassis, after which it became safe.
B-58A bombers were in service with the US Air Force from 1960 to 1970. In total, 116 such aircraft were built, and during operation lost 26 units. The high cost of equipment, the complexity of operation, and the breakdown record-breaking for its class, led to a fairly rapid withdrawal from service and replacement with other aircraft.
The precautions proposed by the developer of the bomber fully paid off. Compliance with restrictions on hazardous areas and other measures avoided damage to equipment and infrastructure or serious personal injuries. Abnormal situations associated with the effects of engines or avionics were managed to prevent.
At the same time, in practice, the importance of safety measures in relation to the chassis has been repeatedly demonstrated. Wheel ruptures and rack struts on landing, mileage or taxiing were quite common. They clearly showed why it is not necessary to approach the aircraft until the landing gear cools down.
However, throughout the life of the B-58A, the accident rate remained quite high. Various incidents were caused by the complexity of maintenance and piloting and other factors. Thus, an overly complex aircraft turned out to be dangerous not only for a potential enemy, but also for its pilots or technicians. However, compliance with simple rules and recommendations made it possible to sharply reduce the danger of technology and avoid unnecessary losses.