Chennai/New Delhi: With the search for the missing Indian Air Force (IAF) transport plane over the Bay of Bengal continuing without much headway, the Indian space agency has decided to postpone the testing of its air breathing engine to a future date, said a senior official. "There are no signs of any IAF plane debris on the sea. The search is on," a senior official of Indian Coast Guard told IANS. "The testing of the scramjet engine has been postponed without any timeline. We do not want to pressurise since the search for the IAF's AN-32 plane is on over the Bay of Bengal," a senior official of ISRO told IANS preferring anonymity. Officials of the Indian Space Research Organisation (ISRO) had earlier said the scramjet engine would be tested this week. During the testing, the air space would be required to be kept clear so that no plane comes in the path of the speeding up rocket and traffic in the sea is also stopped. Aircraft and ships of the IAF, Indian Navy and Indian Coast Guard are searching over the Bay of Bengal for any signs of the missing AN-2 plane, which went missing on July 22 with 29 people on board. Officials said before the launch of any rocket, IAF, civil aviation and naval authorities would be informed about the rocket flight timings so that the air and sea are clear. Traffic on the sea is stopped so that ships/boats do not come in the path of the falling burnt out stages/rocket engine or even the rocket when they fall into the sea. According to ISRO, the scramjet engine will be tested on a RH-560 sounding rocket. The scramjet engine, used only during the atmospheric phase of the rocket's flight, will help in bringing down the launch cost by reducing the amount of oxidiser to be carried along with the fuel. According to the Coast Guard official, there are no traces of oil on the sea surface that could be connected to the missing plane. "We are also very much disturbed and worried about the 29 people on board the IAF plane and their relatives. Even if one takes into account five people in the families of the missing people then around 150 family members are directly impacted," the Coast Guard official said.