Testing – a bit of humor

1st F-22 fighters failed to cross 180 meridians
When trying to push F22 fighters "on their way" from the Hawaiian Islands to the Kadena Air Force base on the Japanese island of Okinawa, a software failure "in navigation" forced the pilots to deploy and return to where they fled. Now the true nature of the “navigation anomaly” has become known.

According to DefenseTech with reference to the Associated Press, the fighters failed to overcome the so-called "line of change of dates" - a conditional line, on different sides of which the local time is the same (with accuracy to the time zone), but the calendar dates differ by one day. The line of change of dates passes along the meridian of 180 degrees with individual deviations.

Changing dates is done (and generally makes sense) only when using local time. When crossing the line of change of dates it is necessary to either add or subtract one day - depending on the direction in which the movement is carried out. Apparently, this Earth Paradox, realized by the participants of the Magellanic expedition, was forgotten by the developers of the F-22 Raptor.

The consequences of this forgetfulness were very tangible. The fighters in the flight, Defense Tech notes, the fuel and navigation systems, as well as - in part - communication, failed.

Only one pilot managed to contact the experts of the developer (Lockheed Martin). Several pilots tried to reboot the fighter's software in flight.

"To beat" the mistake was not possible, but the fighters themselves and their pilots survived, which in such a situation should be considered undoubtedly lucky. Return to the Hawaiian islands required additional refuelling in the air.

Subsequently, the "navigation anomaly" was corrected, and the F-22 still arrived at the destination air base.

2nd Errors of Dividing by Zero

The company Motorola tested a new processor for autopilot on a fighter in Israel. Everything was postponed. The pilots on the tests went "to bend the terrain" from the north to the south of Israel. The fighter perfectly flew on autopilot over the plain part, over the mountain part, over the Jordan River valley, and approached the Dead Sea. Without flying to it, there is unexpectedly a general drop of the processor, the autopilot turns off at full speed, the pilots switch to manual control, and plant the fighter.

The processor was sent for refinement and testing. All the tests passed without failure. The real inspection started again. The fighter flew over all territories, but when approaching the Dead Sea: a general downing, automatic pilot disconnection, manual landing.

Long tests could not reveal any defects. After prolonged attempts, it was found that the autopilot programs when calculating control parameters according to deeply scientific secret formulas divided by the value of the current height of the fighter over the ocean level. When approaching the Dead Sea, the height became zero, and the processor, when divided by zero, gave a total drop. Before this incident, no one thought that aircraft could fly below the ocean level.

Three Recognition systems, as it was in the 1970s

Somewhere in the late 1970s - tests of the American Armed Forces "Sergant York". to destroy helicopters. ZSU was equipped with a image recognition system.
During the tests, a helicopter targeted her unsuccessfully, which she could never recognize. But recognized as a helicopter a fan in the toilet, located in the 800s meters from the ZSU. He successfully struck him.

4 is F-16s on their feet

Tests of the American F-16 fighter were conducted, of course, in the northern hemisphere. At the final stage, the plane decided to test somewhere in Latin America, but already on the other side of the equator. When the aircraft was transferred to autopilot mode, it automatically turned up its legs.

5 is Dramatic re-initialization

In Afghanistan, two guidelines observers (Canadians) lighted the target for bombing it. After the bomb was dropped in the GPS receiver, the batteries ended. The calculation quickly replaced them. As a result, the rocket went wrong. The reason is simple. After the device is powered, the variables responsible for the coordinates of the target are automatically initialized by the coordinates of the current location. The guards died from a close break.

6 is Pilot of Illyushin

At the tests of the Su-24 regularly occurred failure of the bombing equipment. Moreover, this only happened if the test pilot Ilyushin arrived at the target. The reason was also not difficult. Only he entered the target with an accuracy that exceeded machine accuracy. The machine zero was obtained, after which it failed due to an attempt to divide by zero.

7 is Undetested

This example is also very characteristic, although, strictly speaking, it does not directly relate to software development, but demonstrates the importance of testing. This problem arose, most likely, on the MBR 15A30, and already after placing it on combat duty. At the launch, the rocket came out of the mine and exploded at a height of several meters above the ground. The reason was also not the most difficult. The shirt is cooled by an oxidant, after which it enters the combustion chamber. In the rush of the adoption of the new complex to the next anniversary, small improvements were made to the engine launch system, which were not properly tested. As a result, the pyrovalve worked with a great delay. The oxidant did not enter the cooling pipe, and the heat resistance of the pipe was only enough to get the rocket out of the mine.

8 is Choose the right data types
On June 4, 1996, the Ariane-5 missile exploded due to a programming error. The rocket control system used modified software that previously worked successfully on the Arian-4, but the Arian-5 accelerated faster than the previous modification, as a result of which at 40 seconds of flight one of the auxiliary subprograms attempted to convert a long whole value into a short without checking the value of the value, then went beyond the boundaries of the type, the rocket control system was disconnected, and it was blown up by command for self-elimination. Direct (along with the carrier missile was lost communication satellite) and indirect damage from this software failure was estimated at half a billion dollars.

9 is Division by Zero again.
The story of the problems of the U.S. Navy missile cruiser "Yorktown". It is an experimental, so-called "smart ship" (smart ship), the most important life support systems of which are controlled by computers without human participation. It is run under the operating system Windows NT 4.0. So, one day, all this macho, being in the open sea, for three hours without a little got into a complete stupor because of the software. Moreover, this occurred due to the completely blatant malfunction of one of the operators, who was engaged in the calibration of the valves of the fuel system and recorded a zero value in some of the cells of the calculation table. Then there was the operation of dividing by this very zero. Even the cheapest calculator can cope with such nonsense, but here in the operator's terminal the system made a memory overflow error. Moreover, the error quickly spread to other computers of the ship's local network, a chain reaction began, and according to the well-known domino principle, the entire on-board system collapsed. Which was able to restore and reboot only after 2 hours and 45 minutes, during which the healthy combat ship remained essentially helpless and uncontrollable.