Flight with disabled controls: Difference between revisions

Revision as of 08:41, 19 July 2024

Revision as of 14:58, 21 July 2024

Line 3:

{{Use American English|date=March 2023}}

Throughout a normal flight, a pilot controls an aircraft through the use of [[Flight control surfaces|flight controls]] including maintaining straight and level flight, as well as turns, climbing, and descending. Some controls, such as a [[Yoke_Yoke (aeronautics)|"yoke"]] or "stick" move and adjust the [[Flight control surfaces|control surfaces]] which affects the aircraft's attitude in the three axes of pitch, roll, and yaw. Other controls include those for adjusting wing characteristics (flaps, slats, spoilers) and those that control the power or thrust of the propulsion systems. The loss of primary control systems in any phase of flight is an emergency. Aircraft are not designed to be flown under such circumstances; however, some pilots faced with such an emergency have had limited success flying and landing aircraft with disabled controls.

Control system failures resulting in disabled controls have resulted in a number of [[List of accidents and incidents on commercial airliners|aviation incidents and accidents]]. Some incidents occurred where controls were not functioning correctly prior to take-off, others where the failure developed during flight. A loss of control can occur when an unrelated failure, such as an engine failure, causes damage to control related systems. For instances, in several incidents an engine broke apart, causing the failure of main and redundant [[hydraulic system]]s, which disabled all control surfaces. Some or all controls can become inoperative from [[extreme weather]] conditions, due to collisions, due to poor maintenance or mistakes made by maintenance workers, as a result of pilot error, due to failures of the [[aircraft flight control system|flight control system]], or due to design or manufacturing flaws.

Line 9:

==Control techniques==

===Normal flight===

In [[Aircraft_flight_dynamicsAircraft flight dynamics|normal flight]], maneuvering an aircraft requires some combination of controls, which are often interactive in their effect.

* For instance, to climb to a higher altitude, the pilot can increase thrust which will cause the aircraft to climb while maintaining airspeed.

** Alternately, the pilot may climb by pitching the aircraft up, though in this case airspeed decreases.

* Normally to make a turn, the pilot banks left or right by adjusting the ailerons on the wings to increase lift on one wing, and decrease lift on the other. The asymmetric lift causes asymmetric drag, which causes the aircraft to yaw adversely. To correct the yaw, the pilot uses the [[Rudder#Aircraft_ruddersAircraft rudders|rudder]] to perform a coordinated turn.

** In a multi-engined aircraft, the loss of thrust in one engine can also cause adverse yaw, and here again the rudder is used to regain coordinated flight.

===Flight with disabled controls===

Line 61 ⟶ 62:

In these incidents, there was a failure of control system components themselves (e.g. cables, hydraulics, flaps, slats, ailerons, rudder, stabilizer, trim tabs, auto-pilot). ''(Control system fatigue failures are here, but improperly installed or incorrectly adjusted controls in the next section).''

*[[United Airlines Flight 585]], [[Boeing 737]], March 3, 1991. The hydraulic servo that controlled the rudder had an un-commanded actuation, resulting in a [[Boeing 737 rudder issues|"hardover"]] where the rudder unexpectedly reversed. All 20 passengers and 5 crew members were killed when the pilots were unable to regain control, and the aircraft slammed into the ground and exploded.

*[[USAir Flight 427]], [[Boeing 737]], September 8, 1994. A second rudder hardover crash killed all 127 passengers and five crew members on board.

*[[Eastwind Airlines Flight 517]], [[Boeing 737-200]], June 9, 1996. A third rudder hardover incident. This time, the crew were able to regain control and land the aircraft successfully. All 53 occupants on board the 737-200 survived with one flight attendant injured. This flight was instrumental in resolving the cause of the 737 rudder issues, because it was the first flight to land safely, allowing investigators to interview the pilots and study the aircraft.

Line 72 ⟶ 73:

*[[Air Moorea Flight 1121]], a [[de Havilland Canada DHC-6 Twin Otter]], on 9 August 2007. Deterioration of the elevator cable from frequent takeoffs and landings, and likely jet-blast from larger aircraft, caused the cable to snap one minute after takeoff. The plane then nosedived and crashed into the ocean near [[Moorea-Temae Airport]] soon afterwards, killing all 19 passengers and the sole pilot.

===Control failures due to maintenance errors===

In these incidents, the failure of control system components was caused by improper installation or adjustment of control systems components by maintenance personnel.

* [[Air Astana Flight 1388]], an [[Embraer E-Jet family|Embraer ERJ-E190]], November 11th11, 2018. The aircraft suffered severe control issues from an incorrectly installed aileron cable shortly after taking off from Alverca Air Base, [[Portugal]]. The flight crew struggled to control the plane for about 90 minutes. During that period, they lost control of their aircraft multiple times but found they could gain more control by activating direct mode for flight controls which disconnects the FCM (flight control module). This greatly increased controllability of the pitch and yaw-[[Aircraft principal axes|axes]], but control of the roll axis was still limited. After 90 minutes and two unsuccessful landing attempts, the flight crew managed to land the plane at [[Beja Airport]]. Everyone aboard survived the incident, but one suffered a leg injury.<ref>{{Cite web |last=Ranter |first=Harro |title=ASN Aircraft accident Embraer ERJ-190LR (ERJ-190-100 LR) P4-KCJ Lisbon |url=https://aviation-safety.net/database/record.php?id=20181111-0 |access-date=2022-09-18 |website=aviation-safety.net}}</ref>

* [[Emery Worldwide Airlines Flight 17]], a [[Douglas DC-8|McDonnel Douglas DC-8]], February 16th16, 2000. Crashed shortly after taking off from [[Sacramento Mather Airport|Sacremento Mather Airport]]. The crash killed all three crew members. The investigation found that a control rod to the [[Elevator (aeronautics)|right elevator control tab]] detached, causing a loss of pitch control while taking off. The disconnection was caused by the failure to properly secure and inspect the attachment bolt during prior maintenance.

*[[Air Midwest Flight 5481]], a [[Beechcraft 1900D]], on 8 January 2003. On takeoff from [[Charlotte/Douglas International Airport]], the aircraft pitched up and stalled, despite the captain attempting to push the yoke for full elevator down. The aircraft smashed into a US Airways hangar 37 seconds later, killing all 21 passengers and crew aboard and injuring one person on the ground. The NTSB found out that the plane had been overweight and that during maintenance, the tension turnbuckles that governed elevator movement had been set incorrectly by an inexperienced mechanic. This caused the elevators to lose control authority upon takeoff.<ref>{{cite web|url=https://www.ntsb.gov/doclib/reports/2004/AAR0401.pdf |title=Loss of Pitch Control During Takeoff Air Midwest Flight 5481 Raytheon (Beechcraft) 1900D, N233YV Charlotte, North Carolina January 8, 2003 |date= |access-date=2014-03-08}}</ref>

===Controls damaged by explosive device/weapons===

Line 108 ⟶ 111:

===Controls damaged by structural failure===

* On 4 April 1975, A [[1975 Tân Sơn Nhứt C-5 accident|Lockheed C-5 Galaxy]] (registered as {{not a typo|68-0218}})]] making the first flight of [[Operation Babylift]], had the failure of the rear loading ramp, causing the cargo door to open explosively. This caused an [[explosive decompression]], and in turn, severed control cables to the tail, causing two of four hydraulic systems to fail, including those for the rudder and elevator, and leaving the flight control with only the use of one [[aileron]], [[Spoiler (aeronautics)|spoilers]], and power. The crew had to wrestle at the controls by adjusting the power setting and using the remaining one aileron and spoilers in order to return to [[Tan Son Nhut Air Base]], but ended up crash landing in a [[Paddy field|rice paddy]], killing 138{{efn|The number of fatalities vary depending on the source, but official accounts state 138 of 314 on board were killed.}} of the 314 people on board.<ref>{{Cite journal |date=1978 |title=Last Flight From Saigon |url=https://books.google.com/books?id=TmSApdkHyWIC |journal=USAF Southeast Asia Monograph Series |publisher=Diane Publishing |volume=IV |pages=29 |isbn=1-4289-8211-6}}</ref><ref>{{Cite web |last=Ranter |first=Harro |title=ASN Aircraft accident Lockheed C-5A Galaxy 68-0218 Saigon-Tan Son Nhat International Airport (SGN) |url=https://aviation-safety.net/database/record.php?id=19750404-0 |access-date=2022-08-19 |website=aviation-safety.net}}</ref>

===Controls damaged by explosive device/weapons===

Line 118 ⟶ 121:

*On 1 February 1943, the ''[[All American (aircraft)|All American]]'' [[Boeing B-17 Flying Fortress|B-17F]] was in formation with other bombers of the [[414th Expeditionary Reconnaissance Squadron|414th Bombardment Squadron]] to return to their base near [[Biskra]], [[Algeria]] when two [[Messerschmitt Bf 109]]s attacked the lead bomber and the ''All American.'' The first was downed by the bombers but the second continued its attack while flying towards the ''All American'' until its pilot was shot dead by machine gun fire and collided with the ''All American'', making the bomber have its left [[horizontal stabilizer]] sheared off and leaving a huge hole at the tail section. The only thing holding the B-17F together is the metal frame connecting the tail section and the rear gunner.<ref>{{Cite web |date=2016-08-07 |title=Commentary - A new perspective on a challenging day at work |url=http://www.charleston.af.mil/news/story.asp?id=123438088 |archive-url=https://web.archive.org/web/20160807134932/http://www.charleston.af.mil/news/story.asp?id=123438088 |archive-date=2016-08-07 |access-date=2022-09-01 }}</ref><ref name="Leone">{{Cite web |last=Leone |first=Dario |date=2017-11-09 |title=THE STORY OF "ALL AMERICAN", THE B-17 THAT MADE IT HOME AFTER HAVING BEEN SLICED BY THE WING OF AN Me 109 |url=https://theaviationgeekclub.com/story-american-b-17-made-home-sliced-wing-109/ |access-date=2022-09-01 |website=The Aviation Geek Club |language=en-GB}}</ref><ref>{{Cite web |last=WarbirdsNews |date=2013-06-27 |title=WWII's B-17 "All American" Separating Fact and Fiction |url=https://warbirdsnews.com/warbird-articles/wwiis-b-17-all-american-separating-fact-fiction.html |access-date=2022-09-01 |website=Vintage Aviation News |language=en-US}}</ref> This caused the rudder, electricals, oxygens systems to be damaged, losing the tail wheel and having only one operating elevator cable when the other control cables were destroyed.<ref>{{Citation |title=B17 All American ~ (Rev. 2a) (720p HD) |url=https://www.youtube.com/watch?v=_OAPgo1iUvM |language=en |access-date=2022-09-01}}</ref> Despite the mid-air collision, none of the crew on board were injured and the B-17F still remained airborne. The other bombers slowed down to maintain formation with the ''All American'' to protect it from potential attacks from other [[Messerschmitt Bf 109]]s, which never happened. The B-17F managed to land back at the base with the tail section dragging the landing strip.<ref name="Leone"/>

{{clear}}

==Accidents involving experimental flights==