Human error-power supply failure to air traffic controller radar screen at IGI, New Delhi

In an incident involving human error, an electrician at Indira Gandhi International (IGI) airport, New Delhi switched off a miniature circuit breaker (MCB) while fixing an electrical fitting. This MCB as it is reported, is on the line supplying power to air traffic controller (ATC)  radar screens and screens went blank. The standby power (may be diesel generator) came into line in a few seconds and rebooting of all consoles and restoration took about 45 minutes.

Meanwhile, the air traffic controllers having tough time,  guided the planes for safe landing with their experience. All departures were put on hold in between. As it is during such emergency times, Murphy's law showed its application once again. But the experienced personnel guided even a plane or two, low on fuel to land safely without panic.

From various reports in the internet about the incident, there seems to be failure of, or no uninterrupted power supply (UPS) / inverter backup directly connected to ATC radar system, as the screens went blank. That it took sometime for standby power to come into line, indicates that this is a diesel generator (DG) set power supply. This takes about 30 seconds as we experience in apartment complexes or cinema halls. Generally, people use UPS even for domestic computers, because of fear of losing data. Also, because of power cuts,  people use inverter widely at home and business houses. For critical systems, normal power supply should be through inverter/UPS so that any failure of power supply on upstream side will not affect the operations. Now-a-days, solar powered inverters are also available in the market. This should be in addition to the other backups for use. MCB/any other switch should be located on upstream side of these UPS/inverter, rather than on the downstream end so that mistakes like these will not happen. May be the authorities were confident of their backup systems.

Generally, risk assessment is same for aviation and nuclear industries. The risk assessment should be reviewed and measures should be taken to reduce risk levels. It is horrible to think of so many planes in the air without guidance for landing. 

To avoid such mistakes as in this case, there is a need for safety work permit system as practiced in all industrial facilities, for carrying out any job having impact on human lives, property and or environment. Also, that this important MCB could be switched off by mistake indicates that critical safety systems are not protected or its importance is not recognized. Authorities have to review entire safety practices, identify critical systems having impact on persons/property/environment and prepare documented procedure for implementation. Suitable caution boards/warning signs/names and contact numbers of authorities to be contacted in case of need should be displayed near these critical items. A nodal authority (safety officer) should be identified for entire ATC under  whom, permission/approval should be given for various works so that there will not be any lapse. If more than an authority is identified, there may be a situation that one will not know about permission/approval given by the other. Also, lockout/tagout (LOTO) system, if feasible needs to be put in place. 

Apart from power failure like above, it is possible that due to hardware or software glitch or even entry of insects/lizards, the screens can go blank or computer system can hang and for such a situation also, one has to plan for diverse redundant systems to avoid surprise/panic. Whenever, there is no communication between computers or computer and signal receiving/emitting towers or no change in data for a specified time (may be a second or milli second or some other duration depending upon the criticality), audio-visual alarms should be incorporated to alert the concerned personnel for immediate action.

http://www.dnaindia.com/india/report_radar-screens-at-igi-airport-atc-go-blank-outgoing-flights-hit_1797953

http://www.indianexpress.com/news/igia-radar-screens-go-blank-flights-disrupted/1071724/

http://timesofindia.indiatimes.com/india/Power-put-off-by-mistake-IGI-Airport-radars-go-dead/articleshow/18410667.cms?

http://www.indianexpress.com/news/radar-screens-go-blank-again-at-igi-airport/572005/2

Infrared thermography - use it to know about impending electrical fire in your place

Yesterday (14.12.2012) there was an article in The Hindu, about infrared thermography and its use to detect  heating of electrical systems at the point of electrical cable input joints due to over load, loose contacts, improper wiring, etc. The heat emitted is read by the portable device and temperature is displayed to decide about whether it is within or above the limits. I also heard earlier from my colleagues that wall mounted thermography devices are also available to monitor continuously about critical electrical systems.
As most of the fire mishaps are attributed to electrical short circuit (more than 40%) that led to loss of lives, property damage, use of infrared thermography for electrical safety inspections in residential buildings, shops, public places, etc will help in saving us from the perils of fire.
For a long time, I had this question in mind about knowing the health of electrical wiring in my apartment. Fires in apartments, multi storey buildings endanger human lives of all and one should check about electrical safety aspects in the building.
From my electrician, I found that generally, the wiring lasts for 15-20 years, though industrial wiring lasts for more than 30 years as per information from colleagues in power supply department. However, these are theoretical and based on experience limited to specific conditions.
As the author in his article mentioned, over loading is a reason for electrical fires. Wiring gets deteriorated quickly  under excess loads and the general information about life of electrical cable can't be applied universally. And, it is human tendency to add electrical loads with or without knowledge about electrical safety. At least at home front, it is the lack of knowledge on electrical safety that keeps people to add electrically operated kitchenware, electronics, etc. Tripping of MCBs will not lead to thinking by the residents for reasons, and instead, they just put it back and resume with the work.
And, in factories, it is the greed to prolong till it breaks without understanding or may be underestimating the costs to be incurred in case of fire. It is good that insurance companies are giving a thought to electrical safety audits. In many of my posts in this blog and in my comments in newspaper websites, I stressed upon the role of government agencies, regulators and insurance companies for enforcing electrical safety audit without which heavy premiums, penalties and punishments should be the order of the day. Only then, everybody will become aware of electrical safety and other issues and save themselves from fire mishaps and its consequences.
As mentioned in the article, there is company called CSR Impex Private Limited (C.Vidyasagar Reddy, Ph: 040-65212780, 9440066907)  which is involved in use of this technology for the past ten years to inspect electrical panels of various establishments, especially software companies. (I did not check with the company but as I believe in electrical safety audits to know the healthiness of electrical systems, I thought that I can reproduce this information appeared in the newspaper for use by all).

Safety of cockroach killing sprays

Last week, my wife was in the kitchen and suddenly she shouted for help. I ran to her only to see that she is in a state of shock. Later, I was told that the gas burner was lit for cooking. After seeing few cockroaches nearby, she sprayed the killing chemical from the container around the cockroaches. Immediately, the spray caught fire from the gas burner and the flame came towards her. She turned off the burner knob and went into shock. I never thought that spray will be within flammable limits and this taught me a lesson.

Earlier, few years ago, when I sprayed the same chemical for killing cockroaches, over the electrical switch board and also inside the electrical winding section of kitchen mixie and then switched ON the electrical point, the MCB tripped in the house. Without understanding the reason, I set it ON and again switched ON in the kitchen. This time MCBs tripped at home as well as at the LDB in the ground floor of our apartment complex, from where power cables are drawn to my residence. Then, I set it ON. Next, when I switched ON the mixie, there was burning smell from it. Then only it occurred to me that the spray caushed short circuit and lead to tripping of MCBs and coil burning.