About 800 pilots belonging to the erstwhile Indian Airlines went on a strike early on Wednesday demanding pay parity with Air India pilots and better working conditions, leading to cancellation of over 20 flights and disruption of many others by several hours.

In a swift and tough response, the Air India management declared the strike illegal, derecognised the Indian Commercial Pilots' Association (ICPA) and sealed its offices in Delhi and Mumbai.

To tide over the crisis, AI has decided to rope in 150 management pilots — executive pilots — to operate the flights, an airline official said.

The ICPA gave the letter intimating about the strike to AI last night after conciliation talks with the management before the chief labour commissioner failed.

The 800-odd striking pilots belong to the erstwhile Indian Airlines and owe allegiance to the ICPA. The merged entity — Indian Airlines and Air India — has about 1,200 pilots.

The remaining 400 pilots who mostly operate international flights belong to the Indian Pilots Guild (IPG).

Passengers had a torrid time with flight schedules going haywire and getting little information about when they can take off.

At least 20 AI flights were cancelled since midnight. These included AI 469 Del-Raipur via Nagpur, AI 214 Del — Kathmandu, AI 216 Kathmandu-Del, Del-Bangkok, Del-Srinagar and Del-Leh. Passengers of two flights to Mumbai were accomodated in one flight.

Eight flights from Delhi and 11 from Mumbai were cancelled this morning while several others were delayed by more than three hours.

"We have derecognised the ICPA, the strike is illegal and they have committed contempt of court. We are likely to move the court soon," AI spokesperson said.

The ICPA offices in Delhi and Mumbai have been sealed early this morning.

The ICPA claims that while the Air India pilots enjoy a big fixed salary component, the same is almost minuscule for the former IA pilots.

The Association claims that while their entire pay package depends on the hours they fly every day, the airlines has been curtailing the number of flights by 30 to 40 per cent.

"The management has appealed to the pilots to restrainthemselves and not go in for the irresponsible act, especially when the process of conciliation is on," the AI spokesperson said.

He said the government, the civil aviation ministry and all stakeholders are seriously involved in resolving the issue.

A three-member Justice Dharmadhikari committee, formed to look into HR related issues of Air India, has started functioning from this Monday and it is expected to submit its recommendations in three months, he said.

The ICPA decided to go on strike following breakdown in talks involving the association, the airlines management and the chief labour commissioner. Talks were being held over a period of several weeks.

The Association claimed that the management has violated the memorandum of settlement signed in November 2009 on implementing the Sixth Pay Commission recommendations.

"The management has instigated us to go on a strike so that they can derecognise our union. They have done it in case of two major unions — AIR corporation employees union and the union representing the aircraft engineers," ICPA president Capt.A S Bhinder said.

The ICPA had given strike notice on February 23 demanding better working conditions and fixed pay component.

The union, which had threatened to go on strike from March 9, had deferred their agitation till March 15 following tripartite talks with the carrier's management and the CLC.

Later, the Delhi high court restrained them from going on strike from March 16 since the conciliation process had started.