1972– Dec 29, Eastern Airlines Flight 401 Crash, Everglades, Florida — 101

lornajarrettblanchard December 29, 1972

— 103 NationMaster.com. Encyclopedia, List of Notable Accidents and Incidents Com. Aircraft
— 101 NTSB. AAR. Eastern Air Lines…L-1011, N310EA, Miami, Florida, Dec 29, 1972. 1973.
— 101 South Florida Sun Sentinel/Kaye. “Flight 401 1972 Jumbo-Jet Crash…” 12-29-1992.
— 100 Mondout, Patrick.
— 99 Faith, Nicholas. Black Box: Why Air Safety Is No Accident. London: 1996, p. 96.

Narrative Information

NTSB: “Abstract An Eastern Air Lines Lockheed L-1011 crashed at 2342 eastern standard time, December 29, 1972, 18.7 miles west-northwest. of Miami International Airport, Miami, Florida. The aircraft was destroyed. Of the 163 passengers and 13 crew-members aboard, 94 passengers and 5 crewmembers received fatal injuries. Two survivors died later as a result of their injuries.

“Following a missed approach because of a suspected nose gear malfunction, the aircraft climbed to 2,000 feet mean sea level and proceeded on a westerly heading. The three flight crewmembers and a jumpseat occupant became engrossed in the malfunction.

“The National Transportation Safety Board determines that the probable cause of this accident was the failure of the flightcrew to monitor the flight instruments during the final 4 minutes of flight, and to detect an unexpected descent soon enough to prevent impact with the ground. Preoccupation with a malfunction of the nose landing gear position indicating system distracted the crew’s attention from the instruments and allowed the descent to go unnoticed.

“As a result of the investigation of this accident, the Safety Board has made recommendations to the Administrator of the Federal Aviation Administration.” (NTIS Technical Report Standard Title Page, NTSB 1973, ii)

The aircraft crashed into the Everglades shortly after being cleared by Miami Approach Control for a left turn back to Miami International Airport. Surviving passengers and crewmembers stated that the flight was routine and operated normally before impact with the ground.” (NTSB 1973, 1)

“History of the Flight

“Eastern Air Lines, Inc., Lockheed L-1011, N31 OEA, operating as Flight 4O1 (EAL 401), was a scheduled passenger flight from the John F. Kennedy International Airport (JFK), Jamaica, New York, to the Miami International Airport (MIA), Miami, Florida.

“On December 29, 1972, the flight departed from JFK at 2120 with 143 passengers and 13 crewmembers on board and was cleared to MIA in accordance with an instrument flight rules flight plan.

“The flight was uneventful until the approach to MIA. The landing gear handle was placed in the “down” position during the preparation for landing, and the green light, which would have indicated to. the flightcrew that the nose landing gear was fully extended and locked, failed to illuminate. The captain recycled the landing gear, but the green light still failed to illuminate.

“At 2334:05, EAL 401 called the MIA tower and stated, “Ah, tower this is Eastern, ah, four zero one, it looks like we’re gonna have to circle; we don’t have a light on our nose gear yet.”

“At 2334:14, the tower advised, “Eastern four oh one heavy, roger, pull up, climb straight ahead to two thousand, go back to approach control, one twenty eight six. ”

“At 2334:21, the flight acknowledged, “Okay, going up to two thousand, one twenty eight six. ”

“At 2335:09, EAL 401 contacted MIA approach control and reported, “All right, ah, approach control, Eastern four zero one, we’re right over the airport here and climbing to two thousand feet, in fact, we’ve just reached two thousand feet and we’ve got to get a green light on our nose gear.”

At 2335:20, approach control acknowledged the flight’s transmission and instructed EAL 401 to maintain 2,000 feet mean sea level and turn to a heading of 360’ magnetic. The new heading was acknowledged by EAL 401 at 2335:28.

“At 2336:04, the captain instructed the first officer, who was flying the aircraft, to engage the autopilot. The first officer acknowledged the instruction.

“At 2336:27, MIA approach control requested, “Eastern four oh one, turn left heading three-zero- zero.” EAL 401 acknowledged the request and complied.

“The first officer successfully removed the nose gear light lens assembly, but it jammed when he attempted to replace it.

“At 2337:08, the captain instructed the second officer to enter the forward electronics bay, below the flight deck, to check visually the alignment of the nose gear indices.

“At 2337:24, a downward vertical acceleration transient of 0. 04 g caused the aircraft to descend 100 feet; the loss in. altitude was arrested by a pitchup input.

“At 2337:48, approach control requested the flight to turn left to a heading of 270° magnetic. EAL 401 acknowledged the request and turned to the new heading.

“Meanwhile, the flightcrew continued their attempts to free the nose gear position light lens from its retainer, without success. At 2338:34, the captain again directed the second officer to descend into the forward electronics bay and check the alignment of the nose gear indices.

“At 2338:46, EAL 401 called MIA approach control and said, “Eastern four oh one’11 go ah, out west just a little further if we can here and, ah, see if we can get this light to come on here.” MIA approach control granted the request.

“From 2338:56 until 2341:05, the captain and the first officer discussed the faulty nose gear position light lens assembly and how it might have been reinserted incorrectly.

“At 2340:38, a half-second C-chord, which indicated a deviation of +/- 250 feet from the selected altitude, sounded in the cockpit. No crew-member commented on the C-chord. No pitch change to correct for the loss of altitude was recorded.

“Shortly after 2341, the second officer raised his head into the cockpit and stated, “I can’t see it, it’s pitch dark and I throw the little light, I get, ah, nothing.”

“The flightcrew and an Eastern Air Lines maintenance specialist who was occupying the forward observer seat then discussed the operation of the nose wheelwell light. Afterward, the specialist went into the electronics bay to assist the second officer.

“At 234:40, MIA approach control asked, “Eastern, ah, four oh one how are things comin’ along out there? ”

“This query was made a few seconds after the MIA controller noted an altitude reading of 900 feet in the EAL 401 alphanumeric data block on his radar display. The controller testified that he contacted EAL 401 because the flight was nearing the airspace boundary within his jurisdiction.’ He further stated that he had no doubt at that moment about the safety of the aircraft. Momentary deviations in altitude information on the radar display, he said, are not uncommon; and more than one scan on the display would be required to verify a deviation requiring controller action.

“At 2341:44, EAL.401 replied to the controller’s query with, “Okay, we’d like to turn around and come, come back in,” and at 2341:47, approach control granted the request with; “Eastern four oh one turn left heading one eight zero. ” EAL 401 acknowledged and started the turn.

“At 2342:05, the first officer said, “We did something to the altitude.” The captain’s reply was, “What?”

“At 2342:07, the first officer asked, “We’re still at two thousand, right” and the captain immediately exclaimed, “Hey, what’s happening here?”

“At 2342:10, the first of six radio altimeter warning “beep” sounds began; they ceased immediately before the sound of the initial ground impact.

“At 2342:12, while the aircraft was in a left bank of 28’, it crashed into the Everglades at a point 18.7 statute miles west-northwest of MIA… The aircraft was destroyed by the impact.

“Local weather at the time of the accidents was clear, with un-restricted visibility. The accident occurred in darkness, and there was no Moon.” (NTSB 1973, 2-5)
….
“The accident survivors sustained various injuries; the most prevalent were fractures of the ribs, spine, pelvis, and lower extremities. Fourteen persons had various degrees of burns; Seventeen persons received only minor injuries and did not require hospitalization.” (NTSB 1973, 6)
….

“Aircraft Wreckage

“The terrain in the impact area was flat marshland, covered with soft mud under 6 to 12 inches of water. The elevation at the accident site was approximately 8 feet above sea level.

“The left outer wing structure impacted the ground first; the No. 1 engine,. and then the left main landing gear, followed immediately. The aircraft disintegrated, scattering wreckage over an area approximately 1,600 feet long and 300 feet-wide. No complete circumferential cross-section remained of the passenger compartment of the fuselage, which was broken into four main sections and numerous small pieces. The entire left wing and left stabilizer were demolished. No evidence of in-flight structural failure, fire, or explosion was found.” (NTSB 1973, 8)
….
“The captain’s and first officer’s altimeters both indicated approximately 75 feet below sea level…. Functional tests of the captain’s and first officer’s attitude director indicators revealed that both units were capable of satisfactory operation.” (NTSB 1973, 9)
….
“There was no evidence of in-flight fire or explosion. After impact, a flash fire developed from sprayed fuel. Some of the burning fuel penetrated the cabin area, causing 14 passengers to suffer various degrees of burns on exposed body surfaces….

“The search for the aircraft and the initial rescue efforts were coordinated by the United States Coast Guard, which was notified of the accident by Miami tower controllers. Helicopters were airborne almost immediately from the Coast Guard station at Opa Locka, Florida. The crash site was located about 15 to 20 minutes later. Despite the total darkness and the swampy condition of the site, as well as the relative remoteness of one group of survivors from another, rescue efforts were started immediately and were completed approximately 4 hours later, Sixty-eight survivors were airlifted to local hospitals.” (NTSB 1973, 10)

“Most of the survivors were located in the vicinity of the cockpit area, the midcabin service area, the overwing area, and the empennage section; these sections were located at the far end of the wreckage path. In contrast, most fatalities were found in the center of the crash path. Crushing injuries to the chest were the predominant causes of death.” (NTSB 1973, 11)

“Analysis and Conclusions

“It was concluded from the investigation and the data obtained from tests, that the aircraft powerplants, airframe, electrical and Pilot static instruments, flight controls, and hydraulic and electrical systems were not factors contributing to this accident.

“Investigation of the Air Traffic Control responsibilities in this accident revealed another instance where the ARTS III system conceivably could have aided the approach controller in his ability to detect an altitude deviation of a transponder-equipped aircraft, analyze the situation, and take timely action in an effort to assist the flightcrew. In this instance, the controller, after noticing on his radar that the alphanumeric block representing Flight 401 indicated an altitude of 900 feet, immediately queried the flight as to its progress. An immediate positive response from the flightcrew, and the knowledge that the ARTS III equipment, at times, indicates incorrect information for up to three scans, led the controller to believe that Flight 401 was in no immediate danger. The controller continued with his responsibilities to the five other flights within his jurisdiction.

“The Board recognizes that the ARTS III system was not ‘designed’ to provide terrain clearance information and that the FAA has no procedures which require the controller to provide such a service. However, it would appear that everyone in the overall aircraft control system has an inherent responsibility to alert others to apparent hazardous situations, even though it is not his primary duty to effect the corrective action.

“The destruction of the fuselage, with the possible exception of the cockpit area, was to such an extent that the generally accepted factors which affect occupant survivability could not be applied. Survivability in accidents generally is determined by these factors: a relatively intact environment for the occupants, crash forces which do not exceed the limits of human tolerance, adequate occupant restraints, and sufficient escape provisions. A useful distinction may, therefore, be made between impact survival and postcrash survival. Impact survival implies that the crash forces generated by the impact were of a nature which did not exceed the limits of the occupant’s structural environment nor the occupant’s physiological limits. Postcrash survival is determined by the occupant’s successful escape from his environment before conditions become intolerable as a result of fire, water immersion, or other postcrash conditions. This requires nonincapacitation and adequate exit provisions.

“From the above, it is evident that two important factors affecting impact survival were exceeded in this accident: loss of environmental protection and loss of restraint. The injuries of most of the fatalities can be attributed directly to these factors. Therefore, despite the fact that 77 occupants survived, the Board cannot place this accident in the survivable category.

“The high survival rate is difficult to explain. The location of the majority of survivors near the larger fuselage sections would indicate that they remained with these sections until the velocity was considerably reduced or until these sections came to a stop. Although the fuselage shell was torn away, thereby exposing the occupants to external hazards, the fuselage structure apparently did not impinge on these survivors. The Board believes, therefore, that the 76 cabin occupants survived because either their seats remained attached to large floor sections or the occupants were thrown clear of the wreckage at considerably reduced velocities.

“A final survival factor which deserves attention is the design of the passenger seats in this aircraft. These seats incorporated energy absorbers in the support structure. Additionally, in contrast with the conventional floor tiedown arrangement of aircraft seats, each of the seat units in this aircraft was bolted to a platform, which in turn was fitted to tracks attached to basic aircraft structure. It was noted that many of the seat units remained attached to these platforms and that failures occurred because the basic aircraft structure was compromised, rather than the platform attachments. Although many seat leg failures also were noted, these failures occurred because forces were applied in an aft direction; the seats are stressed to withstand much lower loads in the aft direction than in a forward direction. In fact, the Federal Aviation Regulations do not have a stress requirement in the aft direction for aircraft seats. The Board is of the opinion that the design of the passenger seats in this aircraft materially contributed to the survival of many occupants.

“The thrust of the investigation was focused on ascertaining the reasons for the unexpected descent. The areas considered were:

1. Subtle incapacitation of the pilot.

2. The autoflight system operation.

3. Flightcrew training.

4 . Flightcrew distractions.

“Subtle incapacitation had to be considered in view of the finding tumor in the cranial cavity of the captain. The medical examiner suggested that the space-occupying lesion could have affected the captain’s vision particularly where peripheral vision was concerned. Additionally, in the public hearing held in connection with this accident, expert testimony revealed that the onset of this type of tumor is slow enough to allow an individual to adapt, by compensation, to the lack of peripheral vision so that neither he nor other close associates would be aware of any changed behavior. It was also noted that the extent of peripheral vision loss, in this case, could not be predicated with any degree of accuracy on its size and location in the cranial cavity.

“It was hypothesized that if the captain’s peripheral vision was severely impaired, he might not have detected movements in the altimeter and vertical speed indicators while he watched the first
officer remove and replace the nose gear light lens. However, the captain’s family,. close friends, and fellow pilots advised that he showed no signs of visual difficulties in the performance of his duties and in other activities requiring peripheral vision. In the absence of any indications to the contrary, the Board believes that the presence of this tumor in the captain was not a causal factor in this accident.

“In considering the use of the autoflight system, it was noted that the go-around was flown manually by the first officer until 2336:04 when the captain ordered engagement of the autopilot. The affirmative reply by the first officer implies that the autopilot was engaged at this time. Verification of such action was provided by the aircraft performance group analysis of the DFDR readout which showed pitch control surface motions indicative of autopilot control in either altitude hold or pitch CWS. [footnote omitted] Which of the autopilots was engaged, i. e., system “A” or system “B,” could not be determined. Testimony by pilots at the public hearing indicated that the first officer would have probably engaged system “B” to the command position with the altitude hold and heading select functions selected, in accordance with general practices. At the same time, the first officer probably selected 2, 000 feet into the altitude select/alert panel.

“At approximately 2337, some 288 seconds prior to impact, the DFDR readout indicates a vertical acceleration transient of 0.04 g causing a 200-f. p. m. rate of descent. For a pilot to induce such a transient, he would have to intentionally or inadvertently disengage the altitude hold function. It is conceivable that such a transient could have been produced by an inadvertent action on the part of the pilot which caused a force to be applied to the control column. Such a force would have been sufficient to disengage the altitude hold mode. It was noted that the pitch transient occurred at the same time the captain commented to the second officer to “Get down there and see if the . . . nose wheel’s down. ” If the captain had applied a force to the control wheel while turning to talk to the second officer, the altitude hold function might have been accidentally disengaged. Such an occurrence could have been evident to both the captain and first officer by the change on the annunciator panel and the extinguishing of the, altitude mode select light….” (NTSB 1973, 14-17)
….

“The other alternative is that one of the pilots intentionally reduced thrust power when he noted that the speed of the aircraft was exceeding the desired speed (160-170 knots) for the flight regime involved. The intentional adjustment, similarly, most probably was made with reference to the airspeed indicators only. If the crew relied on the autoflight system to maintain the aircraft’s altitude, it is conceivable that a correction in airspeed might have been made without reference to other instruments. Of the two possibilities, the Board believes that the throttles were intentionally retarded by one or both of the pilots….

“The throttle reductions and control column force inputs which were made by the crew, and which caused the aircraft to descend, suggest that crewmembers were not aware of the low force gradient input required to effect a change in aircraft attitude while in CWS. The Board learned that this lack of knowledge about the capabilities of the new autopilot was not limited to the flightcrew of Flight 401. Pilot training and autopilot operational policies were studied extensively during the field phase of the investigation, and were discussed, at great length, in the public hearing connected with this accident. Although formal training provided adequate opportunity to become familiar with this new concept of aircraft control, operational experience with the autopilot was limited by company policy. Company operational procedures did not permit operation of the aircraft in CWS; they required all operations to be conducted in the command modes. This restriction might have compromised the ability of pilots to use and understand the unique CWS feature of the new autopilot….

“Another problem concerns the new automatic systems which are coming into service with newer aircraft and being added to older aircraft. Flightcrews become more reliant upon the functioning of sophisticated avionics systems, and their associated automation to fly the airplane. This is increasingly so as the reliability of such equipment improves. Basic control of the aircraft and supervision of the flight’s progress by instrument indications diminish as other more pressing tasks in the cockpit attract attention because of the overreliance on such automatic equipment.

“Pilots’ testimony indicated that dependence on the reliability and capability of the autopilot is actually greater than anticipated in its early design and its certification. This is particularly true in
the cruise phase of flight. However, in this phase of flight, the autopilot is not designed to remain correctly and safely operational, without performance degradation, after a significant failure occurs….

“The Board is aware of the distractions that can interrupt the routine of flight. Such distractions usually do not affect other flight requirements because of their short duration or their routine integration into the flying task. However, the following took place in this accident:

1. The approach and landing routine was interrupted by an abnormal gear indication.

2. The aircraft was flown to a safe altitude, and the autopilot was engaged to reduce workload, but positive delegation of aircraft control was not accomplished.

3. The nose gear position light lens assembly was removed and incorrectly reinstalled.

4. The first officer became preoccupied with his attempts to remove the jammed light assembly.

5. The captain divided his attention between attempts to help the first officer and orders to other crewmembers to try other approaches to the problem.

6. The flightcrew devoted approximately 4 minutes to the distraction, with minimal regard for other flight requirements.

“It is obvious that this accident, as well as others, was not the final consequence of a single error, but was the cumulative result of several minor deviations from normal operating procedures which triggered a sequence of events with disastrous results….

Findings….

3. There was no failure or malfunction of the structure, powerplants, systems, or components of the aircraft before impact, except that both bulbs in the nose landing gear indicating system were burned out….

8. The flightcrew was unaware of the low force gradient input required to effect a change in aircraft attitude while in CWS….

10. The three flight crewmembers were preoccupied in an attempt to ascertain the position of the nose landing gear….

13. The flightcrew did not hear the aural altitude alert which sounded as the aircraft descended through 1,750 feet m.s.l….

16. The flightcrew did not monitor the flight instruments during the final descent until seconds before impact.

17. The captain failed to assure that a pilot was monitoring the progress of the aircraft at all times.

Probable Cause

Recommendations

“As a result of the investigation of this accident, the Safety on April 23, 1973, submitted three recommendations (A-73-l 1 through 13) to the Administrator of the Federal Aviation Administration….

“Recommendations concerning the crash survival aspects of this accident have been combined with those of two other recent accidents were submitted to the FAA on June 15, 1973….

“The Board further recommends that the Federal Aviation Administration:

Review the ARTS III program for the possible development of procedures to aid flightcrews when marked deviations in altitude are noticed by an Air Traffic Controller. (Recommendation A-73-46. )….

“SAFETY .RECOMMENDAT IONS A-73-11 thru 13

“The National Transportation Safety Board’s current investigation of a fatal air carrier accident involving an Eastern Air Lines, Inc., L-1011, N310EA, which crashed near Miami, Florida, on December 29, 1972, has revealed two areas in which we believe early corrective action is needed
to prevent the recurrence of similar accidents.

“The airplane involved crashed about 6 minutes after the crew had executed a missed approach in order to check the status of the nose gear. The green, gear-safe annunciator light had failed to illuminate when the gear handle was placed in the gear-down position during the initial approach.

“Our investigation indicates that at the time of the accident, all three flight crewmembers were engrossed in an attempt to ascertain whether the landing gear was safely extended, and they were not aware until just before impact that the airplane had departed the 2,000-foot clearance altitude.

“The flight engineer was in the forward avionics center, located beneath the cockpit floor and just forward of the nose wheelwell, attempting to ascertain visually, by means of an optical sight tube, whether the gear was locked down.

“The flight engineer was not successful in his attempt to view the rods on the nose lending gear linkage which indicate whether the gear is locked down. If this is to be done at night, a light in the nose wheelwell must be turned on by a switch on the captain’s eyebrow panel. The person who attempts to view the indicator rods must pull a knob located over an optical sight in order to remove a cover on the far end of the sight. In this case, the flight engineer twice noted that he could see nothing – that it was “pitch dark” We do not know whether ( 1 ) the captain ever attempted to turn on the light (the crew seemed to think that the light should be on whenever the landing gear was extended), (2) the light was inoperative, or (3) the flight engineer properly operated the knob which removes the optical tube cover. In any event, the Safety Board believes that this unsuccessful attempt to ascertain whether the nose landing gear was locked down contributed to the distraction of the flightcrew during this flight. For this reason, the Safety Board believes that this system should be operable by one man; therefore, the switch for the wheelwell light should be located near the optical sight. Furthermore, a placard outlining the proper use of the system should be installed near the light switch and the knob for the optical sight cover.

“The reason for the descent from an altitude of nearly 2,000 feet has not yet been determined. The cockpit voice recorder (VCR) indicates, however that the altitude select alert system sounded shortly after the initial descent. This alert system is comprised of a single C-chord and a flashing amber alert light. When the airplane departs the selected altitude by +/- 250 feet, the C-chord sounds once, and the amber light flashes continuously. However, on the Eastern Air Lines configuration, this light is inhibited from operating below 2,503 feet radar altitude. Thus, on the accident airplane, the only altitude alert system warning to the crew that the airplane was descending was the single C-chord. There is no evidence on the CVR to indicate that the crew ever heard the audible warning as the airplane maintained a continuous descent into the ground.

“Therefore, the Safety Board recommends that the Federal Aviation Administration:

1. Require the installation of a switch for the L-1011 nose wheelwell light near the nose gear indicator optical sight.
2. Require, near the optical sight, the installation of a placard which explains the use of the system.
3. Require that the altitude select alert light system on Eastern Air Lines-configured L-1011 airplanes be modified to provide a flashing light warning to the crew whenever an airplane departs any selected altitude by +/- 250 feet, including operations below 2,500 feet radar altitude.” (NTSB 1973, 20-40)

NationMaster.com: “December 29 – Eastern Air Lines Flight 401…crashes in the Florida Everglades, killing 103 of 176 people on board. The crew is distracted by a faulty gear-down light, resulting in controlled flight into terrain. This is the first crash of a widebody aircraft.” (NationMaster.com. Encyclopedia, “List of Notable Accidents and Incidents of Commercial Aircraft.”)

Sources

Faith, Nicholas. Black Box: Why Air Safety Is No Accident. London: Boxtree, 1996.

Mondout, Patrick. “C5 Crashes in Vietnam During Operation Babylift.” Accessed 3-22-2012 at: http://www.super70s.com/Super70s/Tech/Aviation/Disasters/75-04-04(C5Vietnam).asp

National Transportation Safety Board. Aircraft Accident Report. Eastern Air Lines, Inc., L-1011, N31OEA, Miami, Florida, December 29, 1972. Washington, DC: NTSB (NTSB-AAR-73-14), adopted 6-14-1973. Accessed 3-13-2020 at: https://lessonslearned.faa.gov/L1011Everglades/Eastern%20401%20ntsb%20report.pdf

NationMaster.com. Encyclopedia. “List of Notable Accidents and Incidents on Commercial Aircraft.” Accessed 12-15-2008 at: http://www.nationmaster.com/encyclopedia/List-of-notable-accidents-and-incidents-on-commercial-aircraft

South Florida Sun Sentinel/Ken Kaye. “Flight 401 1972 Jumbo-Jet Crash Was Worst Aviation Disaster in State History.” 12-29-1992. Accessed 3-13-2020 at: https://www.sun-sentinel.com/news/fl-xpm-1992-12-29-9203090325-story.html