A C560 crew reported that immediately after takeoff the main cabin door appeared to develop an air leak and a short time later came completely open. An emergency was declared and the aircraft returned to land.
Synopsis
A C560 crew reported that immediately after takeoff the main cabin door appeared to develop an air leak and a short time later came completely open. An emergency was declared and the aircraft returned to land.
Narrative
Passengers were boarded; and as second in command I gave them the standard safety briefing. After the safety briefing I closed and locked the cabin door. I proceeded to the flight deck to begin engine start and checklist duties as the pilot not flying. Engine start; taxi; and all associated checklists were completed uneventfully. There was a slight ATC delay for takeoff due to airport arrivals and departures on both runways at the airport. The departure for Runway XX was assigned and thoroughly reviewed. After a 15 min. ATC delay we were cleared for takeoff on Runway XX. Shortly after calling V1 and just before V2 I noticed the door seal and cabin door lights on the annunciator panel. Immediately after the aircraft became airborne and audible air leak was heard by everyone on the aircraft. The gear was retracted and I pointed out the illuminated annunciator to the pilot in command. At 400 feet the flaps were retracted. The pilot in command requested a call be made to Tower to return for landing. I called Tower with the request to return for landing for a maintenance issue. Tower responded to enter a right base for Runway XX. Once on downwind I informed Tower we were on a right downwind for Runway XX. The pilot in command then requested that I inform the passengers of our intentions. I informed the passengers that we were returning for a minor mechanical issue and ensured that they were both seated and strapped in. The passengers acknowledged. The pilot in command selected flaps 15 while I was briefing the passengers. When I checked back in with the pilot in command he requested the short segment checklist. I performed the short segment checklist and boxed the landing speeds. As we were approaching abeam the numbers for Runway XX; the door came completely open. I turned around to see some newspapers exiting the cabin door and the passengers still seated and strapped in. The pilot in command requested declaring an emergency which I did with Tower. The gear was selected down. On base to final a GPWS warning was heard; acknowledged and I made call outs to the effect that we were slightly low but there was no imminent threat of a terrain incursion. Airspeed was around 150 and we were about 1 mile base to final so I suggested flaps 35 and the pilot in command called for flaps 35. The landing checklist was completed. Once on final I made a call to Tower that we were on final to Runway XX. Callouts were made for slightly low and on speed. The pilot in command's approach was smooth; consistent; and the landing was made on speed. We taxied clear of Runway XX. The decision was made to shut down the aircraft just clear of Runway XX on the taxiway. Since the cause is unknown; no suggestions can be made at this time.
Second reporter narrative
The day started out normally with breakfast in the morning. We reported to the FBO a few minutes early and began preparing for the flight as we normally would. The First Officer went out to the plane and I checked the weather; NOTAMs and picked up the paper Flight Release. I went outside and preflighted the plane with no unusual findings. The First Officer set up the flight deck and loaded the box. We had a question on the routing so we pulled out the charts and verified everything before considering the FMS inputs as accurate. We also conducted the pre departure safety briefing at that time so as to be ready for engine start after loading passengers. The passengers arrived on time and were loaded. I did a final walk around on the plane as I normally do then climbed in my seat while the First Officer closed the door and briefed the passengers. After he joined me up on the flight deck; I called for the Starting Engines Checklist. Again everything proceeded normally aside from one of the passengers coming up to the galley for something while an engine was starting. We called for taxi and were instructed to taxi to Runway XX via Taxiway A. Immediately after becoming airborne we both heard a hissing noise followed by pressure changes in our ears. At first I thought it was a flight deck window; but then the First Officer pointed out we had a cabin door/ door seal annunciator on. Things were busy then as we had to get the gear and flaps up on schedule. Also there was a turn and speed requirement for the SID. As we complied with the turn I had the First Officer request a return to the airport. I remember from that point on the noise being very loud and distracting. At one point the GPWS gave a 'Terrain Caution' which the First Officer and I both agreed did not present a danger of a CFIT. Again runway and airport were insight. We both focused on getting the aircraft safely on the ground. Both engines indicated normally and we focused our attention on altitude and airspeed all the while crosschecking each other and correcting. I called for a landing checklist somewhere on final. Touchdown was smooth and uneventful aside from the fact the main cabin door was open. We taxied clear of the runway and stopped the plane. At first we discussed closing the door and taxiing in. That was quickly identified as a bad decision as we did not know the condition of the plane's exterior or if there was some other damage that could be done. We shut the plane down completely and were met by airport rescue. We checked on the passengers for their safety. They we very happy that everyone was safe; including anyone on the ground had we dropped something from the plane. No injuries were confirmed and after a post flight walk; the plane was tugged back to the facility while the passengers were accommodated in a separate van. I notified the Chief Pilot of the event and current status of things. Airport rescue and police took my name; address and a short statement. We were then rushed off to be drug and alcohol tested due to the test center's hour of operation. After testing was completed; we returned to write the plane up and turn in our times. We are not exactly sure how we ended up in this situation. As such I don't know what suggestions I would offer at this time.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.