P. Jindal, also a noted industrialist, and Surendra Singh were killed when the chopper carrying them went down near Saharanpur in Uttar Pradesh March 31, 2005.

But many were luckier.

Senior Congress leader Ahmed Patel and union ministers Prithviraj Chauhan and Kumari Selja had a miraculous escape in 2004 when the rear portion of their chopper broke on landing at a helipad in Khanvel in south Gujarat.

Former Punjab chief minister Amarinder Singh has survived one such chopper accident when it hit electrical wires soon after after taking off. The cables snapped and the chopper crashlanded from a relatively low height. Singh escaped.

BJP president Rajnath Singh and his vice president Mukhtar Abbas Naqvi had a miraculous escape last year when they were travelling to Rampur. The chopper landed close to a pile of dry grass that caught fire. The pilot, however, immediately took off again and landed at a safe place.

Aviation experts say the primary culprit in most helicopter accidents is the pilots' tendency to operate under Visual Flight Rules (VFR) instead of the Instrument Flight Rules (IFR).

IFR allows pilots to fly by just relying on the instrument panels even if they cannot see anything outside the cockpit windows. The VFR, on the other hand, are used by pilots to fly by relying on what all they can see from the cockpit.

According to the US-based International Helicopter Safety Team, the helicopter crash rate is three times higher than that of commercial planes and an international safety team, of which India is a member, has committed to lowering chopper accidents by 80 percent over the next 10 years.

While the lessons learnt form earlier accidents have forced a series of new regulations, human error and non-compliance of procedures continue to cast a shadow over the safety of helicopter operations, say experts.