Three months after the Israel Air Force grounded its F-16I squadrons following the discovery of carcinogenic material, a senior IAF officer accused the plane's US manufacturer Lockheed Martin over the weekend of dragging its feet in helping to uncover the source of the problem. In March, then-OC IAF Maj.-Gen. Elazar Shkedy decided to ground all F-16I training flights after a high level of formaldehyde was found in the cockpit of one of the aircraft. Shkedy suspended training flights after a number of pilots complained of a bad smell coming from the cockpit of one of the planes. The IDF Medical Branch discovered that the smell was caused by a type of formaldehyde known to be carcinogenic in high concentration. Last month, Shkedy decided to approve the planes for flights - after special filters were installed in some of them - but eight planes remain grounded with high levels of formaldehyde. The F-16I - called "Sufa" (Storm) in Israel - is one of the most advanced combat fighter jets in the world, alongside Israel's F-15I. While Lockheed Martin has been involved in testing the aircraft with the IAF, a senior officer said last week that the air force had expected the defense company to take responsibility for the technical malfunction and to assist in providing a solution. He said Lockheed Martin was hesitant to admit there was a problem since it would reflect poorly on the company, which has sold thousands of F-16s worldwide. One option under consideration by the IAF for the grounded planes is to replace their engines, which might have oil leaks that are behind the presence of formaldehyde in the cockpit. The F-16I has a powerful Pratt & Whitney F100-PW-229 engine and IAF sources said Lockheed Martin should pay for the new engines. "They do not want to take responsibility since it essentially would be an admission that there is a problem with the plane," the officer said. "This happens often with defense industries, which sometimes make faulty products but do not want to admit to it since it would look bad." In response to the report, official IAF sources said Monday that the Air Force enjoyed Lockheed Martin's full cooperation with regard to the investigation and that relations between the two organizations were positive and intact. Lockheed Martin officials have said that the company was providing the IAF with all of the necessary logistical support to find a solution to the problem.